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Tuberific Q&A from one of Bob's eBay auctions

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TNRabbit

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(pair of) SILVER-7 TUBE AMPs

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Post Wed Aug 12, 2009 5:27 am

Tuberific Q&A from one of Bob's eBay auctions

I didn't have time to search but found this transcript of the Q&A from one of Bob's Tube Amp auctions on ebay & wanted to get it down for posterity before it is lost forever (If you look closely, Bob published his Sunfire email address in here!):

"Q: Hi Bob, redstone7 here again from Colorado Springs, I have to ask one more question......is there ever going to be a tube preamplifier offered from your camp right here on E-Bay??? Thanks much, Rob Mar-21-09

A: Hi Rob'stone7, not from me ( I should never say never), but James Sauter IS planning to build an exact copy of the preamp I designed for the Silver Sevens long ago. He may be found on the Carver Fest forum. Thanks again, Bob Carver

Q: continued,, so now there is being fed to the bias pot a filtered neg. DC, that is decoupled from the filter capacitors, that can change with without the lag that a capacitor would cause. It must have been pretty darn fast because I could hook the amp to a scope,set idle to 15ma. suddenly zap a sinewave to it big enough to drive right up to just before clipping, and the sine wave would instantly appear with out gradually climbing up with flattened tops. That was good enough for me!!!!! I have bailed out of tube equipment, am now making chip amps from the latest audio grade offering from National Semiconductor.. they sound very "tubelike" to me (and many others) Just in time because I am getting too old to manhandle heavy iron. nevertheless I still maintain a keen interest in new ideas in tube technology. I would love to see a schematic of these amps..could you send me one to my email? The 6al5 is a high perveance duo diode.I'm trying to imagine how it is implemented..Neal Mar-21-09

A: Hi Neal, I would be happy to send you a schematic....just e-mail me after the auction to remaind me. Don't forget to include your e-mail! Bob

Q: Greetings Bob, I have followed you since the Silver 7, and Tim since the EAR, and I can not think of any other two who have added so much good music to the world. In fact reading of the Silver 7 is what got me interested in tubes...again (built my first tube amp in '57 with bits and pieces of discards, but cost drove me to transistors in 65 and cheap speakers masked the difference). Might it be possible for you to come up with a "kit" or built bias 'controller' that would be adaptable to different amps. I have a Meas Baron tri-tube modified which I love, but 1 bias and 1 balance pot to control 6 tubes per side requires frequent tweeking even though I use current matched tubes. It seems there is much interest in a better bias method. I have seen this in questions for the amps you have offered, and in many of the DYI groups as well. Many not be exciting to do, but it is a much needed product, and important tweek for tube amps. I you'd be swamped with sales too cordially, bud Mar-21-09

A: Hi 'greg, I too have a pair of vintage Mesa Barons with six 6L6's per mono block amp. Beautiful amps! The 6AL5 DC restorer is the answer to your problem, plus it will stop the DC bounce that inevitably creeps into the system as the grid bias "hunts" under dynamic conditions. E-mail me after the auction and I'll send you the complete fix and the schematic as I used in my Baron. Warmest and best, Bob Carver

Q: Hi Bob...thank you for responding to my confusion concerning your bias scheme,,but first I want to say to the bidders:....BID AWAY, BOYS AND GIRLS.I HAVE INDEPENDENTLY DUPLICATED THE ESSENTAL FEATURES AND CAN ASSURE YOU THIS IS THE ONLY WAY TO OPTIMIZE FOR AUDIO QUALITY AND LONGEVITY. SO BID WITH ASSURANCE MORTGAGE YOUR HOME IF YOU CAN GET ONE OR EVEN HAVE A JOB LEFT TO THINK ABOUT IT Ok I think I know where my confusion lies----when I say sliding bias I mean changing the G1 negative voltage....when you say sliding bias you refer to a particular TECHNIQUE to change G1 neg. volt. Consider the neg source half or full wave, there will be a smoothing cap followed by a an RC tage ,followe by maybe another RC smoothing stage..Now follow with a resistor voltage divider WITH NO CAPACITOR ..the center connection now feeds the bias pot..One leg of the volt divider is paralleled with a device that changes resistance with input drive....continued Mar-21-09

A: Not exactly, but close enough for Gov'nt work. Keep that brain going 1000 RPM and we can have a scientific discussion about bias off-line. Bob

Q: dear Bob....thank you for hanging in there with my audio-amatuer forays into mysteries of tube amps. I don't understand your bias stablization...it doesn't jive with your comments which I quote here "the dc restorer eliminated the need to idle each output tube at 50 watts yielding instead an idle power of 12 watts per tube....It works by keeping the dc componant on each output tube grid the exact value throgh the entire audio signal swing allowing perfect performance up to and even beyond clipping" Well, if by dc componant you refer to the negative bias grid voltage this is exactly how I describe my sliding bias scheme. If your bias scheme doen't shift the negative bias as the amp moves away from idle it will soon run into class B operation and really gross distortion. Your previous response says the bias doesn't slide , but if by slide we mean changing the bias voltage , then it MUST slide to my way of thinking...I'm confused cordially neal Mar-21-09

A: Hi '541, ....It jives perfectly with my comments. A sliding bias scheme has too much delay in responding under dynamic conditions OR it has too much control voltage ripple modulation for my taste. Such a scheme must ALWAYS be a compromise between the two. That's because it will have a detector diode, an integrating capacitor, and a time constant comprised of the final smoothing RC filter. The topology is often similar to a meter drive circuit. On the other hand, a DC restorer operates such that the DC value of the waveform on the grid remains where we want it even in the presence of asymmetrical, haversine signals. And its delay time is essentially zero because there is no filter capacitor to charge and therefore no time constant. Works far better, and is far more elegant than a simple and coarse sliding bias circuit. Bob Carver

Q: Bob....Come on..Bob..don't you want to explain to the prospective buyers the magic trick of 12 watts idle ( 18ma. at 660 volts anode) per output tube and not slide the bias to lower and lower negative G1 volts under progressively greater dynamic conditions to keep out of class B operation and unlistenable distortion?? ("My dc restorer is not a sliding bias approach, rather its purpose is to keep the DC value on the control grid at design center etc etc" your words , not mine) we are all waiting with breathless anticipation cordially Neal in Oregon Mar-21-09

A: Continued next following.

Q: Hi Bob, can you say a bit more about how this amp sounds? Can you elaborate on "the sound: This amplifier stands with a small handful of the world's great vacuum tube amplifiers" a bit more, especially sound-wise, which of the great amplifiers are most similar to your amp? Thank you, Frank Mar-21-09

A: Hi '211k, I would say my own Silver Seven's, my Subsequent Silver Sevens with extra output tubes and dual screen regulators. (Two 6550's per amp.) The $30,000 Manley amps, and the Mesa Barons at 150 watts. I've limited this to vintage amps. Hope it helps, Bob Carver

Q: ...which output tubes are used in this amp, 6550's or the kt88's, the write up refers to both articles tim depravacini/stu hegeman and yourself, is there any difference between the carver/pravacini mono's and carver/hegeman mono amps? thank you! david Mar-21-09

A: Hey old friend, these amps use KT88's. The difference is in the front end; these use 12AT7's, 12AX7's, and 6AL5's with KT88's. The Hegeman units use 6AW8's, 12BH7's, and 6AL5's with 6550's. I cannot answer the question which one do I like better because it's just like asking which of your children do you love more. I love them both the same, even though they each possess distinctive audio personalities! Bob Carver

Q: What an honour to be able to ask you a question,Bob. How do you think these amps would match up with Apogee Duetta Signatures' current and voltage loads, and would you recommend running both MT ribbons and bass panels with them ? (Trying to get away from present biamping with chip amps on bass and tube hybrids on MT ribbon and into a more coherent one-amp sound, if that makes sense). Your vintage pair here have come up on the Apogee users' website as one possible ultimate amp for Apogees, which would be wonderful for one who, like me, is just looking for that final and permanent piece of his system. Mar-21-09

A: Hi 'fitte, I prefer the one-amp coherent sound unless the amplifier is not powerful enough to avoid clipping and overload on some of your music. This amp has been designed to run the Apogee Scintilla one ohm speaker....I really worked hard to get it to do that. So it should be a walk-in-the-park for the Duetta. The power increases as the impedance decreases....up to 300 watts, just what the Apogee needs and loves. I would not bi-amp here, perhaps bi-wire with heavy gauge for the bass panels and finer wire for the ribbons. Try it both ways. Bob Carver

Q: Hello Bob, I was reading your writings here and you mentioned that your friend Stu liked the 6550's better than the KT-88's but I see you opted for the 88's on this design,is there a specific reason because of the overall design or is it more about personal preference? The funding is not here to bid on your current effort but I'm right in the middle of re-tubing my MC-275's and your input would be greatly appreciated , Thanks, Rob McRae in Colorado Springs Mar-20-09

A: Hi 'stone 7, Remember that Stu was designing tube amps long ago and the KT88 was very new on our shores. At the time, the mighty 6550 was supreme, was considered the best and the finest, and was used by all the great designers back then. However, the KT88 was on its way. I love both tubes and would be happy with either, but I have a giant stash of NOS vintage KT88's to use from my museum. Bob

Q: Hello Mr. Carver, is there any comparison between these beauties and the legendary Silver series of tube amps you created long ago ?? Could they realistically be produced again, given the growing high-end audio gear market, especially in the tube sector ? Since I was unable to attend CarverFest last year, I'm still hoping to view the Q&A session that was recorded , I submitted questions for you and have yet to learn what your answers were ! Maybe this year !!! Respectfully yours, silver7t1 Mar-20-09

A: Hi '7t1, Oh no! I never got your questions, or perhaps I did and have forgotten. Try again at bob.sunfire@gmail.com., The relationship between the two amplifier designs is what I call crystalized knowledge. The Silver Sevens are similalar to the 520 circuit, whereas these have the cicuit described above. You bet this year! Bob Carver

Q: Hello Bob I consider it a honor to even ASK you a question, let alone receive an answer!LOL Anyways I'm wondering about the transformers, can you disclose what they are for primary Z? Also I don't see a choke in your PSU, is it CRC filtered then? Thanks WOT Mar-20-09

A: Hi 'tour, I have hooked them up to match four output tubes, so in this design, since I have six of them they are intentionally underloaded which allows them to operate such that an easy 180 watts is obtained, and is the reason the output power can increase when havily loaded with a difficult to drive speaker load. All CRC filtering, and with so much that a vintage designer woul find it difficult to believe.

Q: Bob - Oops, forgot that the text mentioned the bias control. I am fascinated by the driver. It looks like a 12AX7 sized T-6 tube, short envelope. I would be interested in finding out what it is. Again, it looks like a 5687. Tim Smith Mar-19-09

A: It's a 12AT7 double mica, military frame grid NOS tube and can easily drive three outputs per plate with a 33,000 ohm resistor following. See the RCA tube manual. Excellent question. Bob

Q: Bob- Will you ever decide to release this tube amp design for production commercially? Mar-19-09

A: Hi '1, I would love to but that would take more vintage parts than I have to spare. I don't know what I'll do when I run out of output transformers, but I'll think of somthing....maybe I'll just clone a Partridge or something, as I still have my old transformer winding machine.Warmest and best, Bob Carver

Q: Hey Bob---just let 'rama know he can find me by going to my eBay page. He can go to the site map, click on find members, and put in tubular_joe. Thanks! Mar-19-09

A: Got it! Bob

Q: Bob - Magnificent amps! A few questions but don't the feel the need to answer if you'd be compromising proprietary information. It looks like the KT88 grids are fed from the 6AL5 cathodes - can't tell, the chassis photo is grainy. Also, are all of the KT88s controlled by a single bias pot (rear of amp?) or does your circuitry handle bias needs - can't tell if there's a bias pot at the rear. Is the driver tube a 5687? That strikes as about the only small tube (non-Russian) that would have the ability to drive a sextet of KT88s. I've built amps for several years, essentially all with regulated pentode output stages; think they sound the best. I recently finished a 45 watt/channel rig that uses Russian 6P41S vertical amp tubes run at 460 on the plates and 185 on the screens, If you're interested I can send photos; email address is ***edited***. Good luck selling these, I hope they find a good home. Thanks, Tim Smith Mar-19-09

A: This is going to be a fast answer...I'm on a two minute time-out computer. The drive comes from a 12AT7. The 6AL5 IS connected to the grids to control the D.C. All the output tubes are cintrolled by a single pot, not for balance so much as for the ability to trim the soundstage envelopment. And yes I would love to see see photoes.

Q: It is a pleasure and a privilege to view your tube amp and to read your Q&A. You are truly a designer for the people, reminiscent of when you took the Stereophile challenge and made affordable gear sound like reference. Sorry for the off topic question but I am dying to know if there is a postscript to the challenge. Cheers! Mar-19-09

A: Hi 'it, Well, the only postscript that comes to mind is that after all these years, the original article is still being posted around the world in several languages and many forums. It suprises me to this day that a single article by J. Gordon Holt has had so much staying power. Thank you for writing, Bob Carver

Q: Dear Bob, Another thought I have is concerning your comment that only four types of circiut designs for tube amps have ever been invented. With your design being a 5th circuit, would it have been possible to design this circuit 50 years ago with the type of componets available at the time or would you have had to add a bunch more tubes and circuits to accomplish the same design 50 years ago. Am I making any sense? Thank you again, Frank E. Mar-19-09

A: Hi Frank, What a great question. sinc`e this amp is built of vintage parts, it would absolutely have been possible 50 years ago. Even the 6AL5 was around back then. But neither Tim nor I were. And yes, you make a lot of sense! Bob Carver

Q: Dear Bob, I have a quick question, for my own information. I like the look of your pots. Are they a pot and or transformer combo that you made. My only guess is maybe McIntosh?? And if your quad wiring and DC Restorer are available to look at on a schematic. ( if your pats. are secure and filed of course). I am not going to copy it at all, just interested, of course! Thanks again, Frank E. Mar-19-09

A: Hi '632, I don't remember where I got the pots....it was so long ago. Remember, I was old when Atlantas sank! I'll send you a schematic if you remind me after the auction, and you are welcome to copy it to build an amp if you wish. Thanks for writing, Bob Carver

Q: Hi Bob How many dB of Global Feedback do you use in these amps? Is the feedback on the secondary of the OPT? Mar-19-09

A: Hi 'Plies, Our amp uses the classical amount of 20 dB and if the output transformer is good enough to support a full twenty dB a switch on the front can change it to 11 db, a contemporary amount often used by modern amplifier designers. I prefer 20 dB. I prefer the full twenty if the output transformer is good enough to support it."
TNRabbit
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From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
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Post Fri Aug 28, 2009 7:21 pm

Re: Tuberific Q&A from one of Bob's eBay auctions

Tubes rule!

That is all, carry on.
Political Correctness...defined

A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.



In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."
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TNRabbit

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Post Mon May 16, 2011 5:10 am

Re: Tuberific Q&A from one of Bob's eBay auctions

The following Q&A posts were made by weitrhino on thecarversite.com. Reprinted here for posterity with Rodney's permission. I've posted them in reverse chronological order (approximately) because I'm too damn lazy to do otherwise. Sue me~ 8)

Q&A rom Bob's last "Black Beauty" auction:

Q: Hi Bob, It's Sgreat again. I have another question about my Citation II. Since your last auction ended I haven't been able to contact you. Have you ever tried the KT 120s in a Citation yourself? I'm at rwwear@bellsouth.net Thanks Robert Apr-25-11

A: Hi Robert, I have indeed installed the new Tung-Sol KT120's in a Citation II. They work great, and here is what you have to do to make 'em work GREAT. First, you must hook your 8 ohm speaker to the 16 ohm tap, your 4 ohm speaker to the 8 ohm tap, and so on. That is because the Big KT120's have a larger output voltage swing, and to make use of it, the transformer tap that yields that voltage swing must be used. Then adjust the bias for a dissipation of about 24 watts for each tube - about 55 ma per tube. It is not critical. The output power will be approximately 120 watts per channel of pure tube power! Great question, Bob Carver bob

Q: Happy Easter Bob & Those amps are Awesome! Good Luck :) Apr-25-11

A: Thank you! You are warming the cocles of my heart, of that is no doubt. And Happy Easter to you! Best wishes and warmest regards this Easter, Bob Carver

Q: Thank you very much Bob, I have had this amp since 1987, and I have been giving uninterrupted care since. I will go for the 2200uf @ 100V, then. It is great to greet you. You have made history. You also continue to make history. I am shure you do not know how many fans worldwide you actually have. Greets also from Robert and Pepe, comrades from a "moving disco" business, where we combined a Crown 1200 for driving 15" JBL E140's in a kliplsh La Scala enclosure, with your M500t for highs (JBL 2425H), and it sounded great. Later I bought the 1.5t for my personal use. Wishing you continue sucess, Hiram Apr-24-11

A: Hi'tx, Thanks for the high-five! You've made my day. 1987 - boy that's a long time, but it's wonderful. Warmest and best, Bob Carver

Q: Hello Bob... are you The real Bob Carver? A question, if you are so kind... I have your. 1.5t amp... It has two blue 2200uf 50 and 80v capacitors... What will be the long term consequences, if I replace them with two 10000uf 100V caps? I am a Great fan of you! Thanks, live long and best regards, Hiram Apr-23-11

A: Hi Hiram, Am I the real Bob Carver? Let me pinch myself and I'll see. OUCH! Yep, it's really me! No problem with the caps; they will work fine. The diodes will be stressed slightly more than normal because the peak charging current will increase slightly, though the average current will remain the same. If you feel like it, you could replace them with the next higher rated current units, but it is not necessary actually. If the original diodes blow in twenty years or so , all that will happen is a blown fuse too. That would be an easy fix, so go ahead and put in the cap upgrade. Happy listening! Bob Carver

Q: Hi Bob, congratulations for your hard work on these amps. You mention the word balance here and there, but the design is single ended with a RCA input instead of balance with XLR input. With some few exceptions such as Conrad Johnson and few others, the hi-end industry seems to be more into a balanced design. A balanced design would obviously almost double the whole circuit of the amplifier but, didn't you forecast any sonic advantage to go into that direction, such as noise cancellation? Some statements are: - Balanced helps with ground loops as well as EM/RF. - Balanced also runs at a higher signal level so it improves S/N Regards, Gerry Apr-21-11

A: Hi Gary, Good thinking! Still, and just the same, I like vintage RCA input jacks better. Here's why: XLR jacks are more complex and do NOT sound better. They were designed to solve a problem that has historically plagued professional sound installations with long cable runs. These long runs tend to pick up hum and static - and balanced helps reduce it to a manageable level. Hum and static have no business in a home Hi-Fidelity system, and with a good installation any hum and noise will be non-existent. And if it is not, balanced will not help one iota, as it will almost certainly be coming from the source itself, not the cable run. Stu Hegeman taught me that the ubiquitous RCA jack yielded great sound, the best sound, and all balancing would do in a home system would add complexity and the ever present danger of the added signal manipulation harming the sound. Here is the final irony: A survey of modern vacuum tube power amps reveals that many have a balanced input jack as well as the standard RCA, BUT, the balanced part is NOT even hooked up inside - it invariably uses only the positive going half of the signal. In other words, it is NOT balanced at all! It is there as a convenience for those who have balanced cables, and the negative side signal is not even hooked up. It is usually left open or it's grounded through a 620 ohm resistor. Single ended sounds better. Great, great question, and one that really needed answering, as false beliefs are so very much alive in any discipline, especially audio it seems! Hope this helps. Best wishes and Warmest regards, Bob Carver

Q: Hi Bob. Alas, I will likely never be able to afford a pair of these amps of (Black) Beauty, but like looking at a Playboy® magazine, I continue to enjoy seeing these and their brethren posted for sale on eBay, glad to see that you're still contributing innovation and sweet music to the audio world, not to mention audiophiles (or is it, audiophools?), and appreciating Tubular Joe's handiwork. Keep 'em coming - I enjoy every one, almost like I'm there listening to them with you! -Dave Apr-20-11

A: Hi Dave, I know what you mean - even though you are not physically here listening with me, let's pretend we are in a great hall listening to the greatest tube amps ever. Oops, what do you mean pretend Kemo Sabe, these are the greatest! Bob Carver

Q: Hi Bob! I know you do magic with your amplifier designs and the entire audiophile world thank you for it, but have you turned to some kind of voodoo magic now? The day you posted these amps on Ebay, was the day that my Carver TFM-45 started to fail on me... Did you build a little voodoo doll of my TFM-45 and are you trying to coherse me to buy another pair of these beautiful amplifiers?? Best of luck with the auction, I hope people realize that these amplifiers are an incredible awesome deal! They are designed and build by one of the greatest legends in the audio world and we're lucky to still have you around coming up with new designs and new products! These amplifiers are truly an instant classic and they will only go up in value, BID AWAY, guys!! Ulises. Apr-20-11

A: I love you Man! I concur: BID AWAY guys!! Bob Carver

Q: Hi Bob, first of all let me say what a big admirer I am of your work. I live in Singapore, will the amps be configurable to operate on 220V? Thanks, David. Apr-20-11

A: Hi'bpd, Absolutely these amps can be set for 220 volts. The transformer has a split primary for just that purpose, and I can easily wire it that way. For that matter, the converesion is a simple thing to do and may easily be performed by a person skilled in the art of changing amplifiers from 220 volts to 110 volts. hope this helps, Bob Carver

Q: Hey Bob, lovely amps. Your amps have old-style attached power cords, and so I infer that you disagree with the current mania for expensive, detachable power cords. Could you shed some light on that design choice? Apr-20-11

A: Hi 'corp, That's a great question; here goes. It was during my Carver days that IEC power cords came into wide use. The reason was simple - it was done for simplicities sake. As the market for audio equipment expanded world wide, it became too difficult for manufactures to keep lots of different cords (different for each country) in stock for an efficient assembly line. Enter the IEC cord, universal to the whole world. As time trolled by, we audiophiles asked for better, more expensive versions and guess what? We manufactures responded with better ones. I was THERE! It was during the eighties. now, I have measured the impedance as well as the DC resistance of the IEC cord, and when the input pins and connectors are included, it turns out that the losses are WORSE with the IEC cord. Think about it - it almost has to be that way - how could a connector, no matter how good, be superior to a hard wired connection with no pins to to make the connection? Don't get me wrong, both hard-wired and IEC cords can work and sound great. Still, and just the same, I prefer a hard wired connection as long as it is practical, meaning I don't have to build many different models for countries all over the world, each with a different connector. It takes about 31 different IEC cords as it is, so it would not be practical to hard-wire that many different units on an assembly line basis. But no sweat for Tubular Joe to hard wire them. Lower losses, less expensive, great sound - these are the hallmarks of hard-wired. I'm actually finding it difficult NOT to change to IEC because of the intense demand to do so. Still, I'm going to stay true to myself and go with hard-wired connections for as long as I'm alive. Hard wired is better!

Q: Hello again Bob. I won a set of your Cheery-180 tube amplifiers last year, and was wondering if it would be possible to "upgrade" them to your new 305 design? Please let me know if this is possible. BrianT Apr-20-11

A: Hi Brian, Welcome again. Yes it would be possible. The path can be two-fold: one, simply replace the output tubes with KT120's, and know that the power will increase about 40 watts into low impedance or difficult to drive speakers. Next step is to add the new output transformer, increasing output power even more, and the final iceing on the cake would be to replace all four transformers (two power transformers and two output transformers). The sound won't change though, but the power will! A lot. Bob Carver

Q: Mr. Carver you are the man . Keep on doing it. In the past you've always though of us who couldn' afford others "High end" Please build tubes for us. Your admirer. Albert. Apr-20-11

A: Hi 1949, Well I have often thought of becoming a glass-blower after watching one at a glass arts fair long ago. It's hard to blow tubes though - putting the vacuum inside would be really tough - I don't think my poor lungs have enough sucking power to suck all the air out before I could put the small metal thingy-do things that go inside in. Thanks for the accolade, you have helped make my day! Fun comment! Bob Carver

Q: Mr. Carver, The rumors have it, that you are no longer employed by Sunfire? With these new tube amplifiers, do you have any plans of starting yet another company? If so, what other products might you produce? Your devoted fan, Ray Camble. Apr-18-11

A: Hi Ray, The rumers are right, but my heart and soul are still with Sunfire. Beyond that, I'm not saying.

Q: Greetings Bob, I was wonderig if you could explain to me the differences between your new "Black Beauties" and your Carver Silver-7 amplifiers, aside from the power rating differences? Thank you for your time, Tom Reitz Apr-18-11

A: Hi Tom, Actually, I have to say that even after all these years, the similarities far outnumber the differences. I think that must be because both were designed with perfect in mind. I know it sounds funny to say that, but it's the truth. I wanted both to have a huge soundstage along with a midnight star-like imaging inside that big acoustic. And I wanted both to last forever! Some of the differences are the color and trim scheme, the lack of transformer covers on the Sevens, and lots more tubes on the Sevens. The front-end circuitry is totally vintage and classical on the Sevens, and balanced long-tailed on the Black Beauties. I could go on and on, but you get the picture, 'nes pa? Good question - thanks for writing and joining in, Bob Carver

Q: HI BOB, I"d love to know more specifics on the sound of these amazing amps ..Any feedback from the buyers of these ? I have a 6973 tube based amp which sounds sooo sweet .Any thoughts or comparisions for us? thank you bill Apr-17-11

A: Hi '839, I have indeed received several comments on the sound of these amps, and sometimes I included them in my Q&A if they (the comments) came in during one of the auctions. I'll go find them - I know they are around here someplace. Give me a few days to round 'em up and stand by. I'll post them on this Q&A forum along with another question. Stand by. Some were so nice they made me blush! Good query, Bob Carver
Last edited by TNRabbit on Mon May 16, 2011 5:47 am, edited 2 times in total.
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
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TNRabbit

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(pair of) SILVER-7 TUBE AMPs

Posts: 13301

Joined: Sun Jan 14, 2007 11:53 am

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Post Mon May 16, 2011 5:13 am

Re: Tuberific Q&A from one of Bob's eBay auctions

From the March 30, 2011 for $7878.00. Somebody got a really nice deal on this pair because these were far more powerful than any sold before. Utilizing KT120 output tubes and a redesigned output transformer, these black amps are rated at 305 Watts, up considerably from the previous 180 watt design. The auction description stated they are 450 Watts at clipping into 1 ohm!

Q: Hi Bob. I'm a little confused, perhaps you can straighten me out. In the first part of the description, you state that "I designed and wound a massive new and powerful output transformer." Later, you mention "Though I have become pretty good at winding them myself, it takes too long" and "I had the thought of getting a commercial transformer company to make them for me according to my plans, but the cost was too high." So,to clarify my clouded brain, are the transformers installed in the BLACK BEAUTY your own handiwork? Also, you mention that "A switch that changes the feedback from classical (vintage) to contemporary." Obviously, by 'vintage,' you must mean a Citation-like sound, right? But by 'contemporary' do you mean more like a current solid-state unit, e.g., Sunfire, or a modern vacuum tube unit, e.g., Audio Research? I'm using other manufacturers names for comparative purposes only; I'm certain that both positions represent the "heart and soul" of Bob Carver! Thanks! -Dave Mar-21-11

A: Hi Dave, I can understand how you are confused because I'm confused myself. If I'm confused how could you possibly not be confused? Now you are making me think! Okay, here goes. I did teach myself how to wind them by copying the original units. Subsequently I changed the design from pie-wound to layer-wound, and have been more than pleased with the way they turned out. I used modern steel and segmented windings. Nobody wanted to pie-wind them - it takes too long, is very difficult, is too expensive and not necessary anyway. At this point in time the units in these Black Beauties are my own handiwork because I have not yet found a transformer house that will wind them for me (at least the way I want them wound), but I will soon. It's hard to wind output transformers - power transformers are easy - and I for one have developed a new-found respect and admiration for the handful of transformer guys on our planet who do it well. As for the feedback switch, "classical" refers to the amount of negative feedback = 20dB. "Contemporary" = 11dB. Modern tube amp designers often prefer less feedback than do vintage designers. That's mostly due to the fact that it's quite difficult to get substantial feedback around modern transformers (built with a rational budget in mind). Sometimes it seems that all the vintage units were designed as cost-no-object. Oh well, It's a good thing I love winding transformers! Hope I did not put you to sleep, Bob Carver

Q: Hi Bob- Not a very exciting question here, but I'd love to see how you package one of these amps for shipment, and I'd like to know which shipper you prefer. I hope you'll be making these until I can afford a couple! Thanks, Clay Mar-21-11

A: Hi Clay, Well, let's see. First I put some special soft cloths around each amp,then a plastic wrap around each one on top of the cloth. After that I put each amp in a box using foam corner blocks. After that, the box is then put inside a bigger box and lots more soft corner blocks plus bubble wrap is used to hold the inner box in place as well as to add extra cushioning. The whole big double box is finally taped closed and banded with nylon banding to hold the box together in case it's dropped down some stairs. Wow! At least I can describe the process faster than it takes to do it! Thanks for asking - I know lots of us want to know the answer to these important questions. I prefer UPS and the USPS. Bob Carver

Q: Hi Bob, Have always truly admired your fine designs. Your tube amp is a beaut. I hope I can afford it. I do not know yet. I now am a proud owner of DOUBLE INFINITY IRS BETAS (2 woofer towers per side) and two main speakers per side as well. I intend to use them in a very large room. The issue of course since the main speakers are very low in impedance, would you recommend the tube amp connected in series (4 ohm tap) to the main speakers or would you still go parallel (they have very nasty impedance drops to the 1 ohm areas). As far as the woofer towers I am confident with solid state. Will be running one woofer tower facing front and another facing rear (omni) with two solid state amplifiers. Since the DC resistance of the towers are 3.2 ohms each could you recommend a stable amp of your own design (solid state again) that I can use for each tower --these will have their own acceleremoters of course... Could older Phase 400 be safe or should I use something else of yours? Mar-21-11

A: H 'ster, I have owned a set of Betas - amazing speakers and one of Arnie Nudell's great and passionate works. The minimum impedance of three ohms or so is not difficult for almost any solid state amp, including any that I have ever designed. A Phase 400 would work great on the woofers. The mids and top with the Emits and ribbons are a different story though. Since they get down very low impedance-wise, we do need an amp that is happy with around an ohm. These Black Beauties will indeed make them sing. I have not actually hooked them up to a pair of Betas, but long ago I did hook up my Silver Sevens and the sound was STUNNING! I'm absolutely certain that results with these amps will be just as stunning, maybe even better. Take a leap of faith and bid happily away! Good query! Thanks for asking, Bob Carver

Q: Hello Bob, First of all I would like to say congratulations on your design and on your longevity and passion for what you do. I have had various different full electrostatic speakers for the last 25 years and for nearly all of those years, I have depended on your amplifier designs to make them sing; Phase 700, Silver 7t, Silver 9t, Signature, Signature Series II. My current system is anchored with a pair of 20th Anniversary Martin Logan CLS's and a Sunfire Signature II small chassis (Architect Series). My question is a simple one. In your opinion, will these 400watt Black Beauties have the power and headroom to make my CLS' sing? Thanks in advance for the answer, Ray Mar-21-11

A: Hi 'gunn, Thanks for making my day - I am definitely happy that you have used my designs for all this time. It seems that together we are still in the arena, even after all these years. I have loved the way vacuum tube amps sound with electrostatics, and have spent countless hours optimizing these amps with CLS's. I continue: When Martin Logan was getting started long ago, I called the founder and asked for a set of CLS's. One thing led to another, and I helped Martin Logan with financing, as well as with some design work. In the process, we two did a lot of listening with his speakers and my amps, were both influenced substantially, and the end result has been amplifiers that work hand and glove with electrostatic speakers. These Black Beauties are perfect for your CLS's! You can even predetermine just the correct output voltage easily, and adjust the Black Beauties to match as well. Great question. Hope this helps, Bob Carver

Q: hello Are you planing to built a preamplifier as good as your amps ? thanks for answering regards from France Mar-28-11

A: Hi from France', I'm not saying. Oh what the heck - yes. But not until next year. When I do build a preamp I want it to be the best sounding, the best looking, and the best there is. I know I can do it - 14 tubes (!) in the phono section alone will give it the best sound and the quietest all-tube phono in the world. Of that there is no doubt. The line stage will be designed with the help of Stu Hegeman and Tim ( I hope) even if I have to travel all the way to another world and another place to work with them. A great preamp is a huge undertaking, pretty much requiring unending devotion day and night. No sleep, no play, no Disneyland,- it's a good thing I love designing preamps. There,I said it! Bob Carver

Q: greetings do these amps produce a lot of heat? would placement/ventilation have to be a consideration thanks Mar-27-11

A: Hi'ct, I am proud to say that these amps do NOT produce a lot of heat. It is relative of course, but as an example, most big amplifiers idle their output tubes at approximately 24 to 45 watts, with 35 watts being the average for a low distortion, wide bandwidth unit. It is the idle power associated with the output tubes that makes the amp get hot. Now for the best part: the DC restorer in these Black Beauties allows the distortion to go very low and yet have the idle power at 11 watts. The tubes are so cool we can hold them without getting burned, though it IS quite uncomfortable to do it. Still, and just the same, we should allways allow some ventilation for for any electroncs with tubes. Thanks for asking, Bob Carver

Q: Hi im new to tube audio. I work alot with large sound systems and night club systems. I wanted to ask you if you worked with tube pre amps at all? I had an idea of building a tube pre amp that could have control on how much saturation or coloring the tubes would effect the sound. Do you think adding a tube pre amp will warm up the sound from CDs or computer based dj programs? Thanks Henry Mar-27-11

A: Hi '53, I like your idea of including a "color saturation" conrol to your new preamp. You remind me of me in that department, because that's exactly the thing I would do left to my own thoughts. And yes, adding a tube preamp will tend to warm up the sound from a CD or computer based system.

Q: Hello again Bob, This is Tim from Wilmington,DE.,last time we chatted you recomended me to salvage some old BOGEN amps for the quality of their transformers. While searching I came across a pair of BOGEN MO200A in good condition but had none of the 8417 tubes that they use. As you know 8417 tubes are very expensive and hard to come by especially since they require 8 8417's per amp. I know it is possible to run 6550's with a loss in power but wanted your opinion on what you would do with them if it was up to you.Would it run with KT88's or even the new KT120's. I would be very greatfull to hear your opinion. Warmest regards, Tim (mmmmcdowell@gmail.com) Mar-27-11

A: Hi Tim, Good score on the Bogens! Actually the 6550's will deliver more power than the 8417. The reason is that they pull down better (by about 35 volts) than the 8417, though they do require about eight more peak drive volts. If you installed the KT120's you would achieve even more power, using the 16 ohm tap as the eight ohm tap, the eight ohm tap as the four ohm tap, and so on. You would have to modify the driver circuits to increase the drive voltage to the grids of the output tubes, though it should be pretty easy to do. If you wanted to use the Bogen circuit, just increase the B+ to the B+ side of the driver plate resistors by about 10 or 20 percent. Then let 'er rip! hope this helps, Bob Carver

Q: How is the bias being adjusted? I see no bias pots. Mar-27-11

A: Hi'tell, The bias is adjusted by a bias pot on the back of the amp. All we need to do is look at the front panel meter and turn the pot until it reads the desired current. All six output tubes are adjusted at once by the single pot. This is possible because of the DC restorer, the circuit that completely eliminates the need for tube matching. The desired bias current is not determined by the designer (me), rather by you and the sound you want from the amp. There is no OPTIMUM bias, rather a RANGE of possible currents, all "in the green". And the choice is yours. Of course I have my personal favorite bias current, and the operating manual that come with these Black Beauties tell us what it is and expands on the concept. Great query, Bob Carver

Q: Hello Bob: I have always been impressed with your products and designs. My question: can balanced inputs be installed in the amps? Thank you, S Mar-25-11

A: Hi again my friend, Yes of course anything is possible, including balanced inputs. But I get great sound with the vintage, ubiquitous RCA inputs, and balanced does not add one bit of sonic improvement - only some convenience if you happen to have balanced cables. Balanced is extremely useful for long, professional, cable runs to help keep down hum and noise pick-up. However, for home systems, single-ended sounds best with far less complexity. A true balanced input requires an extra tube or an input transformer along with the ever-present possibility of compromising the sound because of the added complexity. Still, many folks have asked for balanced, so you are not alone. Hope this helps, Bob Carver

Q: Great looking amps. Have you ever thought about making them in mirror imaged pairs? Thanks, Robert Mar-25-11

A: Hi 'great, great name! Yes I did think of making them in mirrored pairs. Whenever I have a new idea, or don't have one and find myself stuck with my old idea, I make a mock-up of the second idea so I can try it on for size. Well, I mocked up a mirror image amplifier, put the two side-by-side, and did they ever look funny that way! At least they seemed that way to me! When two identical units were side-by-side, the whole system looked like a very serious arrangement. I liked the looks of the system better when they were the same. Great question - can't tell if I answered it though, but I gave it my best. Bob Carver Bob Carver

Q: Hello Bob,I own a pair of modified Infinity RS1's with 9 EMIMS and 16 bi-pol EMITS a total of 32 per column. I use Beta Woofer Columns with the Beta Servo control unit. Mid/high columns I use Antique Sound Lab Hurricane tube amps at 100 Watt P and 200 T. Your previous amp had P/T feature, how do these differ and would this be a major upgrade across the board. Thanks for your response. Mar-24-11

A: Hi - oops, I already answered this question. Read on. Bob

Q: Hi Bob, last time I will annoy you. I was just studying your amps and thinking to myself, what an interesting look they would present with a yellow chassis and black transformers. A big ol pair of Bumblebees, if you will. Think about it. I'm in if you put together a pair like that. Sincerely, Timothy. Mar-24-11

A: Hi '15k, Welcome back! Bumblebees - I like that! I used to build my model planes using that exact color scheme when I was a kid. Yellow wings and black fuselage. I got so stuck on a single color scheme that my little brother hid my yellow dope (model airplane paint). Well '15k, I'll probably build a yellow and black pair, but I promise not to make them HUMMMM and BUZZZZ like yellow and black bees when they are just sitting there (in hover). Thanks for writing, Bob Carver

Q: Bob, First off, I, think your great and these thing are a work of art. I am a rookie when it comes to tubing and mono blocks, so please for give me if i sound at all skeptical. 1st off what is the purpose of the gauges are they for amps or output wattage and if they are for output shouldn't they read at least 300 ? 2nd is that picture of you winding these are the red pair you sold last month ? These look alot like the red pair that was suppose to be the only pair you had last month. I realize the red pair were only 180 watts. The reason I bring this up is that I am dying for a pair, built by Bob Carver even a better bonus, I just want correct info. If your going to build more I would just assume purchase a pair (through e-bay). Not trying to cut E-bay out by any means. Like I said, please forgive me for sounding skeptical but, when buying on line you like to see consistantcies in what your looking at. Tony Mar-24-11

A: Hi '8rnks, The reasons my auctions seem inconsistent is because I have some character flaws. I procrastinate and I am often lazy. I procrastinate when it comes to taking new pictures sometimes, and so I just use the old ones - like me holding a brown amp with my new hat, or me winding the output transformers. The red units are indeed 180 watts, and the Black Beauties are 305 watts. Anyway, please don't be too sceptical - maybe just a little heathy bit. But it is really me. I can pinch myself to prove it! Ouch! It's me alright! Bob Carver

Q: hello Bob, I would like to ask about Tubular Joe if I may. Your lengthy history in the audio world is well known, but I know very little about Joe or his backround. Are you able to shed some light on his involvement with this amp project? Mar-24-11

A: Hi 'shin', Tubular Joe is a sound man here in the Pacific Northwest, is the best and most talented builder of all time I have ever met, does not like his picture taken, builds the amps on his kitchen table in the evenings and on weekends as a pure work of art and love, has a family and a beautiful young daughter named Corina. He sings solo and lead at night in the late night scene here in Seattle, and all the amps he uses on stage are tube amps. There's more, but that's it for now. Bob Carver

Q: Hello Mr Carver... You have been building these amps for Ebay now for a couple years, and by the pricing of them, it would appear they have quite a following. Congratulations on that! My question is not so much about your most recent upgrade to 305wpc, as it is about future offerings. Are you planning other components to go with these amps, such as preamps and such? Also any plans for more powerful amps? Mar-24-11

A: I'm not saying.

Q: In your Sunfire Signature amps (have owned several of them) you were using massive torroidial transformers. I am curious as to why these transformers have little following in the design of tube amps. Are there any reasons for this? Mar-24-11

A: Hi '1 again, Lots of people have asked me that, and the reason is simple. They are perfect up to the last volt-ampere product and beyond that they too quickly plunge headlong into overload oblivion. Non-toroidal transformers overload gracefully and far less abruptly, smoo-o-o-o-thing their way into overload. A very desirable characteristic with tube amps. Great question, Bob Carver

Q: Hello Bob! I was wondering if you could shed some light on how the work of people like Stu and Tim have influenced your work. I know of the story of the 'coffee can' amp, but I am also curious as to what motivated you to go into the audio business to start with. It would seem a daunting task for someone just coming out of school to even being to think about, so I guess the question is who did you look up to in this field, and why? Mar-24-11

A: Hi tropical',That's a tough question, but I'll do my best with it. It's complex but easy at the same time. Both Tim and Stu were my teachers and collaborators when it came to Tube amps. Stu as a ghost from the past when I studied his HUGE body of work, read everything I could get my hands on about him or written by him. Tim on the other hand, is my contemporary and I can still sit down over coffee with him and we can talk and talk. We have shared ideas, thinking and circuits. Both have influenced me a lot. I have to say though, when I first got out of high school, I had not yet met Tim - that had to wait until a dark and rainy night on a lonely, wet street in Germany outside of a Hi-Fi show. Stu Hegeman became one of my early heroes - the guy is like Albert Einstein - everything he did holds up to this day with not a single mistake. He knew how to listen, and he got it right! Nice questions - they make me think, Bob Carver

Q: HI BOB I WAS WANDERING WHY YOU DONT USE AMERICAN MADE SPRAUGE ATOM FILTER CAPS IN SUCH A BEAST? I HAVE HAND BUILT TUBE GUITAR AMPS FOR 5 YRS NOW AND ONLY USE THE BEST PARTS IN MY STUFF, I WOULD OF EXPECTED YOU TO BE AS ANAL AS I AM, WHEN BUILDING SUCH A HIGH END AMPLIFIER. Mar-24-11

A: Hi 'noon - that sounds funny - oh well, I have used Sprague Atoms, and they are amazing capacitors - no doubt about that. The main drawback here is that they are too big to fit inside my chassis if I want the energy storage I have designed for my amp. My "beast" - 305 watts rms - yeah - I guess it is! The E = 1/2CV^2 of the caps I have are actually quite superior to the Atoms in the narrow use I put them to. If there were a better cap with more performance, I would use it. The Atoms ARE preferred (for a variety of technical reasons) for guitar amps though. You are on the mark with that. There are few things more fun than building tube amps! Bob Carver

Q: Hi ya, Bob! I'm kind of a doofus when it comes to some things, perhaps you won't mind explaining something about these amps for me. You say that "Power is an easy 305 watts rms with a power bandwidth from 24 Hz to 45 kHz, frequency response 2 Hz to 85 kHz, and distortion less than 0.15 % at 305 watts out." OK. I understand the 305 watts rms and distortion stuff, but what's the difference between power bandwidth and frequency response? Aren't they the same? If not, why not? And if they're not the same, how, if at all, would the difference at the low end affect my listening experience when driving full-range speakers, e.g., a pair of Carver Amazing Loudspeakers or similar? Thanks, Man! Nate Mar-24-11

A: Hi again and welcome back! When I was first getting started as a baby inventor, I wondered about the same thing - power bandwidth vs frequency response. Power bandwidth refers to the amplifier's response at high output power just below clipping, whereas frequency response refers to the response at a lower level, usually (and by convention) -20dB. What we measure on the laboratory bench is power response, and when we listen we are listening to frequency response. Frequency response is what we hear - power response is what we measure. It's more complex (as usual)than that, but not much. Super question! Bob Carver

Q: Hello Bob,I own a pair of modified Infinity RS1's with 9 EMIMS and 16 bi-pol EMITS a total of 32 per column. I use Beta Woofer Columns with the Beta Servo control unit. Mid/high columns I use Antique Sound Lab Hurricane tube amps at 100 Watt P and 200 T. Your previous amp had P/T feature, how do these differ and would this be a major upgrade across the board. Thanks for your response. Mar-24-11

A: Hi 'blend, I remember taking a cab from Kennedy airport to Mike Kay's Lyric Hi-Fi in Manhatten, arriving on his doorstep with four large boxes under my arm. I wanted to show off my (then) brand new Silver Seven tube amps. I was traveling the country pitching my wares. Mike greeted me with his Greek accent - "Booby, lets hooook them up to the Big Infinitys, and see how they work." Well, Even though it was long ago, it seems like last week, and before long our faces were locked in ear-to-ear grins. Mike said, "Harry (Pearson) is going to looove them, let's call him." What happened later is another story, but before we left, we tried the amps up his RS1's. That was the first time in my life I had heard them, and I was amazed; the Silver Sevens together with Arnie's Beta towers were absolutely stunning. I won't forget it! These Black Beauties are my latest thinking, and if anything, will sound as good as that system so long ago. Probably even better. You will have the majestic power that is lacking in your existing amp, no matter how good it is - this would definitely be a very serious up-grade! Great speakers - Hope this helps, Bob Carver

Q: Hey there Bob. Is that the expression I might find on my face if I tried to wind a transformer? I'm lucky if I can wind my watch. Oh, by the by, thanks for the tip on upgrading my Citation I. I think we got the noise thing figured out. Might have to touch base with you on the phono stage. Have not tried it out yet. Oh, gotta go, Rush "Working Man" playing....heading over to crank up the db's just enough to annoy my neighbor! Sincerely, Timothy. Mar-23-11

A: Hi '15k again, welcome back. I know what you mean . . . I can wind a transformer, but not my wind-up flashlight. I'm glad the noise is figured out - let me know how you did it; play it soft. No, play it loud! Thanks for the heads-up, and may your listeners have fun tonight. Bob Carver

Q: Hello Again Bob, Seems like youve outdone yourself once again. This one looks even more impressive than the last pair. is the difference power upgrade and tubes? If im understanding you correctly its not the tube the makes the great sound but the circuit designed around the tube that does? The kt120 i have never heard of could you tell us a bit about it and its sound qualities. Can other output tubes be used in this amplifier kt66 kt88s El34 etc. And finally why did audio manufactureres in the past use odball output tubes like 7027s 7581s 7868s 12by(hk) knowing they were going to be very hard to find and costly later on. quicksilver amps is one company that come to mind. Was it because they just wanted to be different than the rest? The same goes with preamp tubes amost everyone made them with 12ax7s 12au7s. thanks again. Mar-23-11

A: Hi again '55, These Black Beauties have a bigger power transformer, a bigger output transformer, and the new Tung-Sol KT120's. To my ear, the KT120 sounds similar to the old Gold Lion KT88, except it can pull down a bit better (by about 40 volts because its plate inside that glass is huge), giving it a more "meaty" sound in the low end. And yes, any of the output tubes you mentioned can be used in these amps - all you have to do is plug them into the sockets, set the bias (using the front panel meter and the bias control), and let 'er rip! As to why did manufactures use oddball tubes? Those choices were made before my time, so I can only guess. My guess is that it was pretty much the individual designer's choice or a cost constraint. I'm almost certain they did not know which tubes would become hard to find 50 years later. For example, the 7027 was an RCA tube, developed by them to compete with the U.S. 6550 and the British KT88. They were VERY proud of that tube! It was also priced (for the amplifier manufactures) less expensively than any other big power tube. They hoped to encourage its use everywhere. And they succeeded! As for the 12BY7 used in the harman kardon amps, Stu Hegeman, the designer, wanted very wide bandwidth so he chose video output tubes. Only they had the high frequency response he wanted. He held the belief that the "Wider the band, the higher the Fi". 12AX7's were so ubiquitous that they stayed around to this day. And they are great tubes too! Hope I did not put you to sleep - if you are still awake, read on. Great questions, Bob Carver

Q: Bob- I have a couple questions, I hope you don't mind. I believe the previous red amps were stated to be 180 watts rms. You say that these "BLACK BEAUTY" amps are 305 watts as a result of the "powerful" KT120 output tubes. Did changing the tubes require beefing up all the other components in the amp as well, for instance, the resistors, capacitors, etc.? Are any changes essentially only in the output stage? Power equals current times voltage in simple terms. Many amplifiers, including some previous Carver models, boast of high output current capability. What voltage/current is this amp capable of producing? Or is it not so critical when using output transformers instead of a direct coupled output like a solid-state amplifier would use? Thanks in advance for your answer! Chris Mar-22-11

A: Hi 'ross8, Holey Moley Rollers! I love questions like this. Here goes - The extra high power comes from three things. One, the new output tubes, two, the new output transformer, and three, the new power supply. It takes all three to get the job done. The new tubes (KT120's) are much more powerful than the KT88's by half again as much. Mike Mathews (the owner of the Tung-Sol tube company) has wanted to build a wonderful tube like this for at least two decades, and he finally did it. This tube is nothing short of fabulous - it has lower distortion (about half as much), more power, and a higher dissipation rating than any other contemporary vacuum tube. I have never met Mike, yet I have known him by reputation for as long as I can remember, and I can tell that he has done everything humanly possible to make a great new tube. He must have a burning passion for output tubes. When I look inside his tube, I can easily see that the grid and screen wires are in tight, perfect alignment. I can also tell that they have been burned in for a long time in his quality control room. As for the output transformer, I changed the turns ratio to optimize the loading (the loading I wanted) for the new tubes, as well as to obtain the desired signal voltage output. I also designed a new power transformer that yields slightly more B+ voltage. All in all, the new transformers just barely fit inside their covers. The original power supply was so over-designed that I did not have to increase its capacity (except for the transformer). Back to voltage-current output: It can deliver 450 watts, and we can slice and dice this power any way we want. 30 amps and 30 volts peak into one ohm, or 10 amps and 70 volts peak into eight ohms. The output stage has a very wide power responce as have all my amps, solid state or tubes. for example, power into an eight ohm resistor is 305 watts, and ON THE SAME eight ohm tap, will deliver 450 watts into four ohms. This means it can drive almost anything.
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Post Mon May 16, 2011 5:19 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Sold on March 10, 2011 for $6701 was the next pair of Bob's tube amps in cherry red with the brown transformer covers. Here's the Q&A direct from the auction pages:


Q: would these amps sound better than Mfa 120s, Marantzes, Macs, Citation 2s any Arc or Conrad amps? Mar-09-11
A: Hi '55 again, Man, you ask hard questions! Most of the amps here are easy to dismiss as not as open sounding - don't get me wrong - each one does sound very good, but for sheer greatness the Marantz nine and the Citation V and II are the true Kings. Still, and just the same, these amps are the best. Geez, I don't know how to answer a question like this! Heeeeelp! Bob
Q: Hi Bob. Why do ribbon speakers 'play' so well with tube amplifiers? Beautiful amps, by the way. Mar-09-11
A: Hi again 'amd, Thank you sir, I think they are beautiful too, if I may say so myself. Tube amps and ribbon speakers go together like bees and honey, or like hands and gloves because they both deliver a large sumptuous soundstage. When combined as one, the sonic results are just exquisite - quite stunning actually. This is a case of one plus one being greater than two. Great question, thanks for writing, Bob Carver
Q: UNFORTUNATLY I CAN'T COMPARE THIS AND MY AMPLIFIERS. MOST REASON BUY THIS IF IS BETTER THAN MY,, I EVEN DOESN'T SEE REAL SOLUTION Mar-09-11
A: Hi 'max8, Trust me, it's better than your old amp. Much better. I just know it is! Take a leap my faraway friend, Warmest and best wishes, Bob Carver
Q: In the past, you have mentioned a characterisrtic of vacuum tube amplifiers that allows them to "listen to the room." You went on to say that this property gave rise to the vacuum tube sound. Would you please elaborate further on this? Mar-09-11
A: Hi Larry, They listen to the room acoustic by using the speakers that are connected to them as microphones. That way, all the room ambiance is captured and amplified by virtue of the amplifier's inverting input; it emerges as a beautiful mix of direct and ambient sound, imparting a sweet and layered depth to the that helps give tube amps their great sound. We can easily perform an interesting experiment to illustrate this. Connect a small hand-held test speaker to the amplifier in parallel with the main speakers and go outside far enough away in the back yard so as not to hear the speakers in the house, but only the small hand-held speaker in our hand. Have someone go into the listening room - clap hands, sing songs, yell out loud, speak and sing happy birthday. We will be able to hear it all over the hand-held speaker. We will hear it all PLUS the room effects. If we try this with a transistor amp we will hear nothing - only silence. It cannot "listen to the room". And without involving the room in the signal, the amp will sound less dimensional and will be devoid of that beautiful soundstage layered depth we all love. Hope I didn't put you to sleep with my long answer - if you're still awake, read on. Great question - thanks for asking. Wamest regards and best wishes, Bob Carver.
Q: Hey Bob. In a previous question, you mentioned that would explain the DC restorer circuitry but apparently got sidetracked. Would you mind finishing the discussion? I'm really interested. Thanks Man! Larry Mar-09-11
A: Hi 'amd, Here goes. The DC restorer circuit is designed to reduce distortion and to reduce the power dissipated in the output tubes at idle. If this sounds too good to be true, it is okay to be suspicious, but honest, it really does all that! Here's how: When the grid of the output tube is driven positive for the tube's power half-cycle, the 6AL5 is not conducting. When it is driven negative, the 6AL5 does conduct, and the net DC value (not the bias) on the grid is held just right for lowest distortion. The bias itself is set by the bias control in a "fixed bias" arrangement. We can show this interesting fact by driving the amp without a load on our test bench, and noting that the idling current remains exactly where we put it with the bias control at idle, AND over the full audio cycle! If it effected the bias, the output current would go up. It does not of course because the DC restorer is doing it's job. Pretty cool, huh? And the tubes last 50 years!
Q: Hi ya Bob. I'm a hobbyist at building tube amplifiers myself. My ultimate aspiration is to some day be able to build amps that sound as good as yours. My question is, what size coupling capacitors do you use in these amplifiers? Thanks, joe. Mar-09-11
A: Hi 'eus, Now that is a question after my own heart because only we nerds ask those questions. I have to be honest, my wife does not care one whit the value of the coupling capacitors that drive the output stage grids. But I do and you do! Yea! The value is 0.12 uf, but remember it's not the value of the coupling cap that's important, but the time constant of the RC network itself. In this amp that is 0.12 X 42,000 = 0.00504 seconds. This value is chosen to compliment the output transformer - small enough to limit the drive below the transformer's saturation frequency, but large enough to allow full low frequency power bandwidth. If it's too large the amp might blow up if we give it a large low-frequency input transient. If it's too small, it won't develop full low-frequency output power, or even a good low-frequency extension. It all depends on the saturation characteristics and magnetizing inductance of the output transformer. I love questions like this, and I hope this helps, Warmest and best, Bob Carver
Q: I've been listening to these amps now after having one a pair at auction and all I can say is - WOW! In my life I've had some great times and experiences, but listening to this amp takes the cake! How do you get it to sound this way? What is your inspiration for such a feat? Mar-09-11
A: Hi 'ott, Wow! You are making my day. Did you one a pair or won a pair? just kidding - thanks for the accolades and I have to say it really warms my blue heart to hear from you. As for how I got it to sound the way it does, I just worked night and day as hard as I could and listened a lot. Stu Hegeman, and especially his Lafayette 550 and Citation amplifiers were my inspirations. Many others as well. Thanks for writing, Bob Carver
Q: Speaker compatibility Hello Mr Carver, thank you for the very detailed explanation on your tube amps. I enjoyed reading your text and the humor applied. You have a great sense of humor as well as you expertise in this field. Your tube amps are beautiful and the specs are amazing, cant wait to hear them or more about them. Two questions if you will please. 1- Would these tube amps be a good match for magnepan 1.6's 2- What was the white out used for that is in your picture of the amps sitting on top of the table? Just some curious humor? If I don't win these amps I am an interested buyer in the future. Best of success to you and your partners in business and this auction. Mar-07-11
A: Hi'10, These amps would indeed be a good match for your Magnepans. Magnepans were designed with linear magnets and a ribbon (or two). As a flat panel speaker they are able to deliver a BIG and believable soundstage that is as sumptuous as it gets (provided they have some help from a great sounding tube amplifier). I developed these amps using the Magnepans extensively, helping me make certain that the match is as perfect as we please. And as we can get! As for the white-out, I can't remember, no matter how hard I try. I have wracked my brain from front to back and for the life of me I cannot remember. Oh well, I probably just used it correct the manual I was writing. Good questions, sorry my answer about the white-out is incomplete. Best, Bob Carver
Q: WHAT TUBES BRAND YOU USED FOR ?? & WHERE THEY MADE ??? Mar-07-11
A: Hi 'ax8, This amp uses Telefunken 12AX7's, JAN 12AT7's, either GE,RCA, or Sylvania. Same for the 6AL5. The output tubes are Silver Eagle KT88's. All are NOS except the Telefunken. Hope this helps. Bob Carver
Q: Bob, I am absolutely intrigued by the ongoing dialogue regarding your new amps and the DC restorer circuit. I wish your recent offerings were within my budget, but it just isn’t to be…. You are an absolutely amazing individual…. Not only a genius in this field, but you take the time to communicate extensively with the rest of the world and do it in a classy, detailed and very courteous manner. I had several different Phase Linear components in the 70’s & 80’s, but family and other things moved me from audio for many years. I am recently getting back into it with a strong preference for the tube sound. I didn’t want to bother you about possibly getting a schematic and have searched for a few days for one online, but I have not been successful. I would be very grateful for a copy of a schematic of one of your new offerings that included the DC restorer circuit. Thanks in advance! Bill Mar-05-11
A: Hi Bill, You absolutely are not bothering me! I love it - you are making my day! I will e-mail you a schematic of the amp after this auction is over. Just remind me so I don't forget. To better understand the operation of the DC restorer, inspect the circuit diagram, and simultaneously read my explanation of how it works in one of the important questions I answered today. Thanks for writing in. Best wishes and warmest regards, Bob Carver
Q: Pleasure honour speaking to U Bob. I apologize if i ask too many questions but ive been collecting vintage audio for few years now and ive spoken to many audio people but never asked a true audiophile engineer. hope can help me out. 1)Have Tube audio principles and electronics improved or changed for the better these days?? 2)Whats the top 3 Vintage 40-60s speakers you ever heard? 2)Can 100,000 speaker, tube amplifier or preamplifier be justified these days? 3)Do Extravagant priced parts improve the sound. it might change the sound but not necessarily make it better. ie, gold, silver, platinum Space age material etc. 4) Do you think the prices paid for vintage amps and speakers on ebay is reasonable and warranted? Is the price worth the sound? Ie Marantz 7c, 9, Craftsmen 500, Mcintosh 275 22 1000, Fisher 1000, 400cx Western Electric tube amps , Tannoy silver, black, Leak, Partridge, 5) Whats your opinion on cables thicker than a mans arm for power/speaker cables? Mar-05-11
A: Hi again '55, I only get 2000 characters, so here goes. Tube audio PRINCIPLES have not changed in the last 50 years, but circuits that use them have definitely improved! That's easy, from 1940 t0 1960 and a bit later - the classic Dahlquist DQ-10, Arnie Nudel's IRS and his "poor man's" version sound a-like Beta (Infinity), Peter Serblin's Electa Amator (Sonus Faber), and finally Apogee's Scintilla. It depends, but at first look, it is very difficult to think so. At least for me. Right. It depends far more on the circuit and the circuit topology. I do believe they are worth the price, and for a variety of reasons, some scientific, and some are a matter of heart. Thick cables thicker than our arms are nonsensical. To the contrary, many British audiophiles are demonstrating better sound with thin cables, especially if a transistor amp is used - the thin cables help a solid state amp sound more like a good tube amp. And I concur. Great questions, hope this helps, thanks for writing. Warmest and best regards, Bob Carver
Q: Hi Bob, I am sure others have asked this question but it is important to those of us that recognize the improvements obtained from high quality powercords. Thanks. Bart Mar-05-11
A: Hi '55, Big amps need Big, high quality power cords. I am very lucky on that score because I was able to scarf up a lifetime (well, maybe not a full lifetime)of high current, extremely high quality cords three summers ago. A low current cord will not be able to supply the current needed for a high current amplifier, so it's important that a power cord that's robust be used, especially when mated with an amp that's used to drive difficult load speakers. Warmest and best, Bob Carver
Q: Wow!!! These are the most beautiful amps I have ever seen. Are you goin to be making more? How about a tube preamp with phono inputs? Very Impressive. Thank you Robert Mar-05-11
A: Hi 'wner, Wow, you think?! Thanks Man, you have made my day! You can be my friend forever! Of course I am going to make more. I can't stop building amps. I couldn't stop even if I wanted to. Just today I decided that if I can get the rights to my favorite tube preamp, I'm going to build one and auction it right here on eBay. If I can't get the rights, then I'll just have to design one from scratch. Luckily I know how. Thanks for writing in - I love your over-the-top enthusiasm! Bob Carver
Q: Hey, great looking amps! I have a question about this DC restorer circuit I've heard about, and I wanted to ask you. Where did the idea come from, and what are the advantages? Thanks, Mar-05-11
A: Hi '008, If your handle was displaced one digit, I would have to run for my life. As for the DC restorer and its operation, the idea came as the result of a great and long-felt need. The historical problem was that in order to get the distortion low, lots of idling current was required - too much by my thinking. Way too much! The DC restorer circuit works by keeping the DC component of the waveform that is impressed on the control grids of the output tubes at the perfect value throughout the entire drive signal. Without it, the correct DC value is lost, and the only way (historically) that distortion could be kept low was to operate the tube at or very close to its maximum dissipation rating. And in the case of many amplifiers, beyond their rating. Not good. I got the idea from my days long ago as a TV service guy. In the old days, TV set were made with vacuum tubes, and it was necessary to drive the picture-tube grid with a signal that retained its DC component. Necessary in order to minimize distortion so that dark scenes were dark and not a medium twilight. Who wanted that?! The DC restorer was almost always a 6AL5 vacuum tube. I stood on the shoulders of others and shamlessly copied their work - darn, those video design engineers wre good! Mostly they used 12BY7 video output tubes.
Q: Bob--Is it true that output tubes have a unique sound? I've heard from my tube buddies that brands like Mullard and Telefunken, for example, have their own tone. If so, how do the KT88 tubes you're using sound? Mar-05-11
A: Hi 'ends, Great question , and one for which the COMPLETE answer has been extremely difficult to find. The following are my experiences and (finally) my conclusions: One, whenever I have installed different brand output tubes, the sound has changed - not much, but enough to hear. For example, changing from a beam power tube to a power pentode results in a shift in focus with a simultaneous shift in soundstage envelopment. Two, I don't have a set of Telefunken output tubes, but I have been able to find sets of Sylvania outputs, RCA's, Tung-Sol, Gold Lions, Shuguangs, GE's, and of course my own Silver Eagles, and others. The Sylvania output tubes are my favorite vintage tube, yielding perfect lab-bench performance and a beautiful ethereal voice to female vocalists. The RCA's and the Tung-Sols have a bit more low-end throw weight, and are a bit more "meaty" sounding, whereas the GE tubes are my all around favorites for general listening - always sounding spectacular no matter what the music is. I could go on and on, but it would take me as long to write about it as it did for me to perform the experiments. After all was said and done, I decided to see if I could get a Silver Eagle to sound the same, exactly the same, as a Sylvania. Actually, it was pretty easy and straightforward to accomplish, and what I ended up doing in the end was to put a switch on the amp that lets us change the feedback from about eleven dB to twenty dB. I also designed the continuously variable bias control to have a huge range so that we can bias the tubes from about six watts dissipation to more than 40 watts. The ONLY reason this scheme can be successful is because of the DC restorer circuit. Three, the final result is that between the feedback switch and the idling current control, we can make the amp deliver a huge soundsatge with stunning imaging inside that stage, or a super tight, centrally focused presentation. Or anything in-between. Oops - running out of characters, goodby
Q: Mr. Carver, I'd like to be sure these amplifiers will operate on a 240 volt mains, and if so, how difficult is it to change them over? Mar-05-11
A: Hi 'ubes, the transformer has a dual winding primary and may be easily changed from 120 VAC to 240 VAC. The connections are a standard industry hook-up, and can readily be performed by by anyone handy with a soldering iron, or I'll do it for whichever voltage you country has. Thanks for asking, Bob Carver
Q: Are you going to have a DIY kit soon? or sell just parts like the tranfromer's :) ? ---- and can I contact you to ask about the build ing of a set of monoblock's You and Tim do have the best looking set tube amp out there - Vtl - Audio research - Cary - Mcintosh Thank You Fraternally and Respectfully Submitted Brother Greg Coleman,MM Mar-01-11
A: Hi'008, I would dearly love to come out with a DIY kit version of this amp, but it is way too hard for me to do at this point. Perhaps someday. Still, you are invited and are very welcome to build your own. Contact me after the auction is over for a schematic, and good luck! There is nothing more fun than building tube amps. Warmest and best, Bob Carver
Q: HI I am interested in your amps ,but I am concerned about the $362 amount that is stated to ship to me in canada t1c1h9 alberta it seems high is this amount correct and if not how much would shipping be . THANKS ps nice looking amps. Mar-01-11
A: Hi'sea, It's indeed shown way too high! I hate the eBay freight computer calculator. For a variety of technical reasons. anyway, the corect amount is $182.36. Besr wishes and warmest regards, Bob Carver
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Surround: Sunfire CRS-3 (x 2)

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(pair of) SILVER-7 TUBE AMPs

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Post Mon May 16, 2011 5:26 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Q&A from the auction ended Feb 6, 2011 for $6701.01. This was the first pair of black amps sold at auction:

Q: Hey ya, Bob! I have owned many amplifiers in the past, including some built by Carver and Sunfire (all solid-state), and have been quite satisfied. (Apparently, I was always searching for "nirvana," since I traded each one out for something else!) With all due respect to the other notable designers mentioned in your "Ghost Questions From the Past," you probably have, collectively, implemented or instigated more innovation into audio amplifiers than any of them. I am fascinated by the information about this amplifier given here, particularly the circuitry, transformer, and historic detail you share. I further realize the 'romance' of tube amplifiers and appreciate and respect your accomplishments with these types of products. But for many of us, the deciding factor is, "How does it sound?" Can you, in 25 words or less (like the old contest rules used to require), describe the difference I might experience if I replace my current solid-state amplifier with these beauties? Thanks, Dave Jan-28-11
A: Hi 'amd, Thanks for the tribute! More, More! You are making my day. Okay,back to business - here goes: When you change to a tube amp you will hear a bigger soundstage, a more enveloping soundstage and within that big acoustic space you will hear spectacular imaging that is extremely difficult for a transistor amp to get right, whereas it emerges effortlessly from a tube amp. A transistor amp will usually paint a flatter picture of sound strung between two speakers, albeit with nice forward imaging. A variety of technical reasons are behind this presentation, still, tube affectionados might say "in your face". Great question, Bob Carver
Q: Davidtwotrees asks... My mentor in this hobby over a decade ago had a nice tube amp, with vintage JBL speakers (Hartsfields). His rig sounded wonderful. Him and his brother invited me over one night for a big tube roll. They switched out the Russian? 300B tubes and replaced them with Western Electric NOS 300Bs that he had paid nearly $1k for. They were incredulous when I said I couldn't tell the difference between the russian tubes and the WE tubes. They swore there was a huge difference. What say you on this, Mr. Carver? Jan-28-11
A: Hi 'trees, Well, there could be lots of reasons of course. One,you didn't hear a difference because there was non to hear. Or the differences were so minuscule that until you listened for a substantial time, you would not be able to pick out the small, subtle differences that DID exist. I believe the main reason is that the differences were so subtle that it takes lots of time to become familiar with them, and only then would we be able to identify 'em. Typically, when a tube is "rolled" (replaced with another)), some characteristics of the amplifier change - output impedance, frequency response, sometimes power, to name a few. These differences often result in subtle shadings of tone or acoustic space, and will often seem HUGE to the audiophile part in all of us, especially after we spend the time to grow accustomed to the sound. In truth, the objective differences are usually small and not important. In other words, if the differences are so small that it's hard to hear them, then they are only differences and probably do not represent something that's better or worse. And of course, we can easily allow our imaginations to believe a difference exists when non does. That shows the humanness in all of us. We can also learn to hear things about acoustic space and imaging, along with other important aspects of the sound. As we learn to hear space, tonality, imaging and other aspects of the soundstage, we will definitely increase our enjoyment of it all when we listen in a quiet and darkened room with the lights almost all the way out.
Q: 3db asks... .) How much time is required to warm up a tube amp? 2.) What are the basic classes of tube amps and define the pros and cons of each class? 3.) Probablly related to the question 2. What are the pros and cons of tubes that use an output transformer to those who don't Jan-28-11
A: Hi 3dB, Wow! Your questions are awesome - they make me feel as if I'm back in my old classroom teaching physics and we all get sidetracked (happened often) into talking about audio. I love having scientific discussions about audio. Okay, here goes. Warm-up time: It's three AM in the morning; the amp currently on my lab bench is the one for this auction; it's cool and at room temperature. I'm going to turn it on and time it with a stop watch - stand by. Just got back from timing - it takes 47 seconds from a cold start to the time when it can deliver full power at rated distortion. As a follow-up, I put in some very old tubes from my stash of Sylvania 6550's - don't know how old exactly - but I'm guessing about 40 years old and well used. Simultaneously I installed some ancient small front-end tubes out of an old console amplifier from the 1950's. Now the warm-up time was much longer. It took a full three minutes to reach the same maximum power and low distortion, though it easily started to play within the same 47 seconds. Tube amp classes: Single-ended class A triode, push-pull class A triode, push-pull class AB pentode. There are more, but these are the most interesting to us. Long ago in the 1930's, nobody knew haw to make a push-pull tube amp without severe "notch distortion".The problem was with the output transformers of the day, and the only way to make a great amp was to use single-ended class A. Then a decade or two later a true genius came along by the name of Williamson; he showed us how to build a transformer that didn't have notch distortion. However, his transformer required a very low impedance drive that was only available from triodes. Still, with his wonderful amplifier, the HI-FI industry took off. The only problem with triodes is they are/were never very efficient, and designers began searching for a way to use high-efficiency power-pentodes. Years passed until Gordon Gow and Frank McIntosh figured out how to build - oops,out of letters
Q: Zumbo asks... How much tube power would be adequate for non-resistive speakers that are not claimed to work well with tubes? Impedance: 4 Ohms Frequency Response: 33Hz - 32kHz Sensitivity: (1 watt @ 3' ) 87dB If I am currently running out of juice in a 5-channel SS amp claiming 175w x 5 @4ohm(Adcom 7605), while only using 2-channels, is it even worth considering tubes? Jan-27-11
A: Hi Zumbo, A good tube amp will usually sound substantially more powerful than a good solid state of equal power rating. In other words, a tube amp will deliver more voltage to our speaker. For example, 175 watts into four ohms is only 24 volt rms. On the other hand, a tube amp will probably deliver about 40 volts, and Black Beauty tube amps will easily deliver over 50 volts. That's double the voltage and since power goes as the square of the voltage, it's a lot of power. there are a variety of technical reasons for this, but in the end, a GOOD tube amp will do a much better job than a solid state amp. Deep question, thanks for joining my auction, Bob Carver
Q: Zildjian asks... How will the bias adjustments be managed in this amplifier? Jan-27-11
A: Hi '1, The bias on this amp is so easy to adjust I can hardly believe it myself. On the back is a pot that adjusts the bias for all the tubes at once. The bias meter on the front indicates how much idle current the tubes are using,so all we have to do is turn the pot until the bias meter indicates the desired current. This brings up an interesting feature of the amp - there is NO optimum bias (idle) current - rather there is a RANGE of proper currents that we can listen to. ANY reading on the meter and the bias current is in the green! No need to match tubes, no need to set the idle current on the mark,as the DC restorer eliminates that need. The main purpose of the adjustment range is to allow us to change the voicing of the amp from a huge tree-dimensional sound stage to a tightly focused up-front presentation. The tubes will idle at about nine watts each. COOL running for a 50 watt tube, and will allow it to last forever, well maybe not forever, but for 50 years. Thanks for writing in, Bob Carver
Q: GranteedEV asks... "Is there any PWM tube amplifier out there, and if so, what are the caveats to its usage?" Jan-27-11
A: Hi '1, when Arnie Nudell, the founder of Infinity, came out with a switch mode amp years ago in the seventies or eighties, I thought I saw the wave of the future, and that all linear amps would be obsolete in short order. He called it the SWAMP amp. I was scared to death that my bell had been rung, as all I had in my line-up was the Phase '700, an "old fashioned" linear amp. Boy was I wrong, and worried for no reason. In the vast gulf of the intervening years, each new year brought many new switch-mode (PWM) amplifiers to market with a universal pair of problems that sounded their demise. One, they blew up regularly - nobody liked that one bit, and most would not put up with it. Two,they sounded bad. Not horrible or anything, but not good enough to be a Hi-Fi amp. Things have improved over the years, and some PWM amps sound quite nice, but they require power supplies that are HUGE. That's because PWM amps do not have a property that's important - it's called common-mode rejection. Anyway, because I was scared to death so long ago, I began building, listening, and studying all about PWM amps. They are better today, but not good enough. Not yet, and I really believe their time is just around the corner - but I have thought that every new year for the last 30 years. Tube amps sound so beautiful and "right" that it's difficult to consider a PWM these days. I have put lots of time and effort into making PWM amps sound good, but the time and effort I have devoted to making tube amps has been FAR more rewarding, resulting in good sound that's actually difficult to believe. Go with tubes! Yea! Excellent,great question. Thanks for writing, Bob Carver
Q: Great looking amps, Bob! How long is the break-in period for these babies? Or do they already sound sweet and only get sweeter? They sure would be at home at my house! Thanks. Jan-26-11
A: Hi nos', Thanks for the accolade - I think they look great too. I was not so sure that all-black would work; I was afraid they might look like giant black blobs. But they look beautiful! You can imagine my surprise when I finally attached the escutcheons and they looked GLORIAS to my eyes. Of course I'm the proud Daddy of these amps, so perhaps I am a bit predisposed to think they look great. I tried champagne gold as well as chrome silver for the escutcheons and chose the color that I thought looked the best with shiny black. As for the break-in period, they start out almost perfect and arrive over the top after about two evenings of listening. Great question, Bob Carver
Q: Hello Bob ( I presume ), I just saw your auction and am the first bidder on the same. The shipping to my country shows as approx 11 dollars. Could you please confirm if this auction is correct and genuine so that I do not get dissappointed in case I win. Max Jan-26-11
A: Hi Max, Darn, the International shipping calculator does not work correctly. I will go to the US Post Office and find out what it would be to India. I will calculate to New Delhi. On some subsequent Q&A, look for my answer - I will sneak it in at the end of my answer. Thanks for joining my auction and definately for being the number one bidder! Warmest and best, Bob Carver
Q: Hello, i live in Italy, some questions for You: -those amplifiers work at 220 volts? -do You can change for me the voltage before shipping? -say me the shipping costs for both to Italy, Naples; -Your suggestion about the preamplifier for piloting of those your jewels (brand?-type?-solid?-tube?), your experience about. Thanks. r. Feb-04-11
A: Hi 'mone, No problem for 220 volts. The power transformer has a split winding, and it is very easy to hook it up for 220 volt operation. Yes, I can change it over to 220 before shipping. No problem at all, and I will be glad to do it. another bidder asked me how much for Italy - I don't remember what the amount was, but just read on down and you'll come to it. I vote for a tube preamp designed by Stu Hegeman, the Citation I. I think it is the best there is. It is a masterpiece! Hope this helps, PS: I may not be able to post any more questions as eBay locks out Q&As with about 24 hours to go before the auction is over. Thanks all for joining this auction. Bob Carver.
Q: Hi Bob, It's believed that the British made amps. have more natural/cleaner sound and US made amps. have more punchy sound, what's your opinion with the Black Beauty against EAR? How do you rate the Ray Lumley Megavox monoblocks? Is you Black Beauty OTL or OCL? How much will cost to ship to Hong Kong? Thanks, Feb-04-11
A: Hi gi' Well, if it's true (it's not) that British amps have a cleaner sound and U.S. amps have more punch, then my Black Beauty has the best of both worlds. It was designed by a Yank (me) as well as by a Brit (Tim). The input stages are pure Brit, whereas the output stages are pure Yank. That old belief is today a false belief, and the punch is a matter of raw power and control. This Black Beauty has a seductive sweetness that reminds me of my EAR, and with considerable more throw weight because of all the big output tubes. I have not had a chance to listen to the Megavox units. Pure power pentode output circuit. Shipping to Hong Kong is about $900 for the pair,but if you win this auction, I'll pay half, and you pay half. Happy bidding my far-away friend, and good luck! Bob Carver
Q: Mr Carver, I understand you may sell Citation 1 preamps? If that is so do you have any available as I would like one if I should win the auction? If not there are a few on Ebay right now if you have the chance could you give some input as to which one might be decent? I dont know what they commonly go for. One is in Washington and I thought I could have it shipped to you for your resto and or upgrade. If I dont get these amps I will keep watching for the next ones. Thanks again Brian Feb-04-11
A: Hi Brian, I have many Citation I preamps and I would be very happy to sell you one of them. These Citations are quite easy to fix, restore, and make as good as new when they rolled off the harman kardon assembly line over 50 years ago. If you win my auction, I'll make you a deal you can't refuse on a beautifully restored Citation. I promise. Here's to you winning! Bob Carver
Q: Hi Bob does this pair of Black Beauty monoblocks have Silver Wings (Eagles)? Just curious. "jay" Feb-04-11
A: Hi Jay, Here's the deal: I used up all my original Silver Eagles so I got some new ones. These new units are very impressive - the glass bottle weighs substantially more, zero microphonics, slightly lower measured distortion, they are tighter together in matching,and they deliver a tad (but not significant) more power. Output Z is also slightly lower, which means thety can drive a very low impedance load with even easier ease. The difference in performance is slight, but my favorite part is this: during tube burn-in time, there was not a single failure for ANY reason. Good catch Jay, you have to look hard at the pictures to notice these tubes are different. Or read the description with great care. Great catch! Bob Carver
Q: Hi Bob, I've just dropped you a question about power supply voltage for European users. Please disregard it - just found the answer among other kind replies of yours. However if you could still advise how these tube amps would work with Carver Amazing speakers taking into account their hunger for high current at very low impedance. I hear no problem with your 600W Sunfire stereo signature amp, or rather I should say - they sound just fantastic together. Many thanks! Feb-02-11
A: Hi 1962, I designed these amps to have a lot of output current. I used a separate power supply for the screens, enormous energy storage (more than 200 joules) and an output transformer with a turns ratio of 17:1 that yields high current as well as very high voltage. They can even drive one ohm. And Amazings. Thanks for the accolade - you have made my day today - thanks again for writing! Bob Carver
Q: Hi, Bob How much for shipping to CANADA My address: 300 Ozerna Road, Edmonton, Alberta, T5Z 3Z8, CANADA Thanks Feb-02-11
A: Hi 1953, Shipping to Alberta is $206 dollars for each amp. If you win, I'll pay for one amp and you pay for the other. That way all you have to pay is 1/2. Happy bidding, Warmest and best,\Bob Carver
Q: That being said I have owned many tube amps. I have ended up liking Eico 35, 60 (modified). McIntoch 75, Leak Stereo 20, and my favorite is my Marantz 2’s. Talking with Robert Hovland the Marantz 2 had nothing special particularly but as it’s components came together as a system with a correct sound that just sounds good on almost all music and all speakers. Most amps and other components sound better and worse depending on the type of musical content, drums, horns, strings, women vocal, etc. I will have to add the respected amps I very specifically do not like; the Harmon Kardon Citation II – way to sterile and dry, the McIntoch 225 – too lean. I was wondering if we could communicate on my likes, equipment, and needs with the end result of paying you to create something for me or even build accordingly. I was thinking of mimicking the basic PS and amp circuit of the Marantz 2 but use a beefed up PS and 6550’s but I really am a novice. 2of2 Feb-01-11
A: Hi '52, It turns out that the Marantz 2 has several truly innovative circuits that made me stand up and take notice. One, Marantz used a unique and very effective high frequency compensation network that allowed the output transformer to deliver every ounce of its high frequency performance. I had never seen it done before, and just stood there in amazement when I tried this scheme on one of my own tube amp designs. Two, marantz also used a unique "low frequency bounce" (That plagued ALL amplifiers!) eliminator circuit that was positively brilliant - wish I had thought of it! Fortunately, it is no longer necessary with the large energy storage capacity that modern electrolytics possess. As far as the Citation II being too dry - I absolutely agree with you and discovered that for myself years ago as a neophyte audiophile still in college. The root problem is that the screen grids are connected to the output transformer in an ultra-linear mode. Whenever I work on a Citation II, I always change its design to pure power pentode operation. The problem then goes away. As a matter of fact, the amplifiers I have found I liked the most over the years have always been pure pentode. The Lafayette 550, the Mesa Baron, and the Citation V come to mind. On a final note, you cannot go wrong using a Marantz 2 power supply and a pair of 6550's. Great observations. Thanks for writing, Bob Carver
Q: Your amp is quite nice to say the least. However it is more of an amp than my application warrants. You mentioned that you used to successfully design with old iron till it ran out. Could you offer up an opinion on the Iron I have? I have stored up output transformers for some time in hopes of building the ultimate tube amp. I have iron; Heath W6, Harmon Kardon Citation II, and Peerless S-271-S. The Citation supposedly is very good and a slight 2500 cycle notch. The W6 by hearsay is supposed to be good. The Peerless is supposed to be one of the top of the list from a respected person (even though the current amps do not sound too good). Iron is very important but I have learned that everything is a system and affects everything else. Like a PP single gain stage triode 50 amp. I tried a choke filter input vs. a cap filter pi type and the choke filter is far superior in that application. I tried different coupling caps and found a wide variety of quality that also affected Sonics. 1of2 Jan-31-11
A: Hi'52, cool question, as It turns out I have built amps with W6 output transformers as well as several with Citation ll transformers. Both are GREAT, GREAT transformers. I'm sure the Peerless is a super transformer as well, but I have not had first hand experience with it. I agree that the circuit, taken as a whole, will dominate the sonic results, including the "iron" and the final circuit topology as well. I vote that you build your amp with the Citation II output transformers you have - they will sound s o o o sweet! Let me know how it turns out - stay in touch, Bob Carver
Q: Hi Bob, I'm a huge fun. My Carver SD/A - 450 is still my primary CD player and I love it! Also, you've done a lot for the industry - Thanks! Second, I'm new to the tube amp side of things, but have always been intrigued by the aesthetic. I'm only just now taking an interest in the technical side. QUESTION: what type/ brand/ model of speaker would you recommend for this type of amp set? Can you also make a recommendation on a pre-amp? Thanks in advance, Kelly. Jan-31-11
A: Hi Kelly, First the preamp - I would go find a good vintage Citation 1 unit. It's a masterpiece that was designed by my hero Stu Hegeman over 50(!) years ago.Stu is long gone, but his legacy lives on. Does it ever! It is among the best there are. Another equally good choice would be a Tim De Paravicini EAR unit, the quietest and best new unit in the whole world. Tube preamps of course. As for speakers, I would go with my own Cinema ribbons - tube amps love ribbon speakers -but first read a review from The Absolute Sound magazine on these speakers, and others as well. The model number is CRM-2. Enjoy your journey! Thanks for writing, Bob Carver
Q: I saw your comments about guys copying the auction info. I just did, but I wanted you to know I am just doing that for my own reading/edification. I copy a lot of stuff into Word. I have an industrial-strength printer at work and I print out a lot of things to read on the train to and from Boston. This is so damned interesting. Wish I could afford such a beautiful piece! Don't arrest me. Thanks, Don Lorenson Jan-31-11
A: Hey Don, Up against the wall! Spread 'em! Assume the position! Yow are under arrest! Just kidding. I'm delighted that you have such a passionate interest in my tube amps, and you are absolutaly welcome to copy and read and share as much as you desire. Thanks for your humor and for your great comment. Warmest and best, Bob Carver
Q: These are beautiful amps! I must also say your skills in sales, promotion and ultimately "desire creation" are (as always in your long career)running 150% here--(I mean that as an absolute compliment!) At least half of audio excellence is PERCEIVED excellence and your skills are nonpareil -- WOW! One thing. Ummm.. "PIE winding"? Surely you mean Pi winding, as in the geometrical theory of size relationships of windings and interleaving of xformers? Or, am I wrong and a hearty diet of baked cherry and apple Americana helped you design? (kidding!) Anyway, kudos; they are the most beautifully made amps I have seen in my 45 year love affair with tubes, as good as 1950s Altec and WE, and your great story makes them seem twice as good. Even if these were a more conventional design like a HK Citation II on steroids they would certainly perform like little else in audio. Again; I am in AWE of your long career as a designer, businessman, and the best hype man audio has ever seen. Cheers! Jan-29-11
A: Hi 'trax, hm mm. Pie r squared or pi r squared? Guess what, you're right and I'm wrong - it is pi! Oh well, I thought there were two national parks most of my life - one, Yos mite, and two, Yos simitee. Whenever I spoke the name it was Yos simitee, and when I read the name it was Yos mite. Not only that, but here in Seattle we have The House of Pie, spelled pie but with the symbol pi underneath the picture of a pie. I have driven by that restaurant a million times and pie for pi got burned in my brain. Some time ago a reviewer wrote about my Silver Seven tube amp and started the story with words to the effect...."Bob does not know if he is Cecil B. DeMill or Albert Einstein." Well, I'm no Einstein, (Just my hero)and nobody can possibly be as flamboyant as DeMill - but he did tell great stories for all the world to enjoy. I'm just trying to get it right amplifier-wise! Thanks for writing and for your beautiful comments. Best wishes and warmest regards, Bob Carver
Q: hello Bob! can you please let me now how hot can the transformers be before it will burn up? my rogue audio amp have been around 50°C and i was worry about it will be desroyed some day if i switch off the cooling fan inside, i really whant to do this as they make some noise when playing music at lower levels.. kind regards tone Jan-29-11
A: Hi tone', what an interesting question! I would say 100 degrees celsius at the maximum - and 90 degrees would be a lot more conservative. 100 degrees is hot to flesh and blood, too hot to hold on to, but for copper, steel, and aluminum it's just a warm summer day. Turn of those fans! Let 'er rip and don't worry. You can get a laser thermometer at Radio Shack and monitor the temperature for awhile, and if it doesn't go over 100 degrees you are okay, albeit 90 would be better. Great question,Bob Carver
Q: You've said previously how you spoke with David Hafler, and more recently, about Frank McIntosh and Gordon Gow contributions, with respect to output transformers, and your new Adamantine Steel units, which you now use as opposed to the "vintage" units originally installed. You've talked about the different tubes that you've used, your time with Tim de Paravicini, the DC restorer, and the impact each has had on output power, etc. We've seen the color change from brown, to cherry red, to black, with and without meters. The real question, to me, has to do with the units' sonics. Does each pair, though all excellent, have a unique sound associated with it, like a fine instrument? Certainly, the various different components have some effect? Or have you deliberately, like a classical artist, made each pair sound unique? You likened various amplifiers' sound to children with different personalities. Can you be a little more specific about these amplifiers and their sound? Thanks a lot, Bob! Jan-29-11
A: Hi 'amd, You have hit the nail on the head, as it were. Even though I am the designer, each of these amplifiers takes on a significant life of its own, independent of me. Even if I wanted each unit be a perfect extension of my desires and wishes, we would find that each one is unique, not majestically different from one another, rather different in the way twins would be. Even identical twins. I have thought about your question a lot, and honestly it has made a substantial impact on me. I find it impossible to characterise the sound of each one - all I know is that with each unit, I'm always carried away to someplace quite beautiful when I'm finally finished tuning it up. I usually spend several days tuning each pair. If I were a poet, I'd be able to better express the joy I feel at the end of that process. In the old days when I built amps on an assembly line, tune-up took less than a minute. Each amplifier does sound unique, but it's nothing I do, it's what a living amplifier does with itself. All I did was start it on that journey. So you see, I cannot be much more specific about these amplifiers and their sound. All I can say is that they seem magical to me. And I could be wrong. Bob Carver
Q: Hey Bob, please finished your answer to 3dB.... Jan-28-11
A: Okay, where was I? Oh yes....Frank McIntosh and Gordon Gow together invented an output transformer that was stunning in that it did NOT have notch distortion AND would work with pentodes... They taught us all how to to do it! At first the rest of the world was stymied because Gordon got a patent on it, but it was not long before very talented engineers understood the conceptual underpinnings of the design, got around the patent, and the pentode has reigned supreme from that moment on. In any event, the patent expired long ago, and the design is now in the public domain. We see we went from single ended class A, to push-pull class A, all the way to push-pull class AB with pentodes. Today, push-pull class AB yields the lowest distortion, the most efficiency, and without a doubt, the most headroom and power. Just the same, old ideas often die hard, and we find that today some of us have a false belief that class A is somehow better and has less distortion than Class AB. It's not true. It was long ago, but not now. In fact, way back then, a class A triode was the ONLY way to get good sound. It's all changed now and a well designed AB output transformer will not have any trace of notch distortion at all, none, zero, and is as pure as pure can be. It's as good as it gets! Awsome question!Thanks for writing and for joining my auction, Bob Carver
Q: 1) You stood the world of audio on its ear (pun intended, naturally) by demonstrating that the sound of expensive, highly revered tube amps could be replicated by a much less expensive SS amp. From a strictly pragmatic audio performance, power capability, and reliability standpoint, does it make sense to buy a tubed amp? 2) For audiophiles who have a background in SS, but are interested in trying out the "tube sound" without having to invest too much, can you recommend gear (can be used or new) which is commonly available, value oriented, and captures the essence of the "tube sound"? Would this best be done via pre-amp or amp? 3) We audiophiles are an obsessive lot. On the condition of tubes gradually wearing out with use, what protocol would you recommend as a compromise between wasting time and money vs maintaining optimum sound quality with tubed equipment? Jan-28-11
A: Hey Man, several of these questions are very scientific; I sense a group of physics students at work here - and I could be wrong, but I don't think so - the questions are very illuminating! Okay, here goes: (1)Yes it DOES make sense to get a tube amp for all the reasons I mentioned earlier and for several others I did not mention. (2)You can get a small Magnavox tube amp on eBay for only a few hundred dollars, and it would be a sweet entry level way to experience tubes. You will be quite surprised if you have not listened to tubes before. Best done at the power amp level, but does not have to be. (3)As far as buying new tubes obsessively when its not necessary, I would replace the small tubes every 20 years or so,whether they need it or not, and replace the output tubes when they check weak on a tube tester. An alternate way to make that determination is to wait until one or more tubes won't bias up properly. The circuit performance of a well designed amp is very uncritical as regards the exact emission of any given tube. The performance in the circuit is substantially (99%) determined by the ratio of resistors and capacitors, and not the detailed tube characteristics. Of course the correct tube has to be installed! Excellent questions,all,and thanks for taking the time to write, Bob Carver
Q: Excuse me Mr. Carver did not realize that she was right to build the amps I thought it was a site that was selling clones remade some its project Excuse me for misunderstanding! regards! Max! Jan-28-11
A: Hi Max, Understood and no apologies needed! It is easy to get confused because others have downloaded my auctions and run them in several sites around the world. They downloaded my text and even my pictures, including some of me at the winder or holding an amp. Very frustrating! luckily for all of us the sites seem to be fading into the background these days, and I don't know of any still in existence. eBay has been very diligent about removing fraudulent postings, provided they know of course. If you find one please let me know - and most importantly, DON'T send any money! Warmest regards and best wishes, Bob Carver
Q: HI!!!Goodmorning i'm intrest to buy the black beauty but not 110 volts i would like the clarification on!for first i would like to know if they are DIY for a project of bob carver??? if is yes....can i order a pair with 220/230volts?how many cost? and the shipping in safetly way until rome italy?how many time imploy to building thems?which type of payment do you accept???paypal is OK?????which assicuration i have on internal parts electronics DIY there are good component iside???no compromise? Thanks i will wait a good replay in a short time thanks regards to ROME! MAX! Jan-28-11
A: Hi '62, I can tell that English is not your first language, still your English is a million time better than my Italian! 240 volt operation is not a problem - the units have split primary power transformers. This auction is not a DYI project, rather it is for a pair of finished and complete amplifiers. As for the cost of the amps, the only way to find out is to join the auction and bid away! This auction is ten days long, and it takes about two weeks for a pair to get to Rome. so about 3 1/2 weeks. I accept any form of rational payment, including pay pal. Best parts. No compromises! As a matter of fact, I almost feel guilty of conspicuous consumption when I look at the parts inside. Thanks for writing and for joining my auction - hope this helps, Bob Carver
Q: Hi can you tell me if this can be set to other voltages other than US like 240v? Also and ide of the shipping cost to the UK? Jan-28-11
A: Hi'eox, It's trivial to set the voltage. The transformer has a split primary, and the work to set it for 240 volts is very easy as well as being a standard operation. I can do it for you if you wish. No sweat. The cost of shipping one amplifier to the UK is $168 dollars, or $336 for a stereo pair. If you win, I'll pay half; I'll ship the left channel to you for free, but you still have to pay for the right channel. Plus a small post office fee - so small it's not worth mentioning. Hope this helps, Bob Carver
Q: Jinjuku asks... With tube amps having a different characteristic when it comes to rounding off amplitude peaks vs solid state and the subsequent two octaves above the fundamental, what does that look like with a tube-pre driving a solid state amp where the pre output voltage is starting to hit it's wall but the SS amp is still well with in it's operational envelope? I'm really hoping that I am asking that question correctly. Jan-28-11
A: Hi 'ku, Well, I think I know what you meant - that somehow, sometimes, tube amps can't properly drive transistor amps. As attorney might say, "objection - assumes a conclusion or a fact not in evidence". Back to tubes: A well designed preamp, tubed or transistorized can drive any Hi-Fi amp there is. For example, the lowest input impedance(hence most difficult to drive) of any power amp I know of is a solid state unit with a 10K input resistor. Any solid state preamp worth its salt can easily drive 10K. And so can a well designed tube preamp. My Citation 1, my Citation IV, my Marantz 7, and my EAR, all tubed units, drive the 10K just fine. In fact, the preamps don't even care if the input impedance is 10K or 1 megohm. The designers Stu Hegeman, Sid Smith, and Tim de Paravicini all made certain their designs could drive extra long cables, and a side benefit of that effort yielded units that can drive any rational power amp, be it tubed or solid state. Hope this helps, Bob Carver Shipping to New Delhi is about a thousand dollars, plus or minus. If you win the auction I'll pay half - so you pay shipping for the right channel, and I'll pay shipping for the left channel. Happy bidding from far away! Bob Carver
Q: If a tubed pre is nearing it's output limit, it will likely have tubey coloration which the ss power amp will accurately reproduce. All the tube line stages I've played with are simple single ended circuits, so have the characteristic low order distortion warmth if taken to their limits. If such a circuit were capable of say 5v instead of two, it would sound much cleaner driving an amp of typical input sensitivity, as the pre-amp would be operating well down in it's linear operating range? Different designers seem to make gear reflecting their own preferences, and can range from squeaky clean (ss-sounding) to pretty colored; colored can be good or bad, depending on what you're after. What is your opinion? Jan-28-11
A: Hi John, That's easy - same as yours. Good luck on your BIG project, and thanks for staying in touch! Warmest and best, Bob Carver
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(pair of) SILVER-7 TUBE AMPs

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Post Mon May 16, 2011 5:37 am

Tuberific Q&A

Ghost questions from the past

Q&A compiled from past auctions:

Q: I have often read that an Ultra linear output tube connection is best for class AB amps. Yur amps are not Ultra linear, what is your opinion on this and what is the difference? Thanks for your time, Tim

A: Hi 't42, Long ago when I first started designing tube amps I read the same literature promoting this same idea. However, an important series of converging experiments taught me that an Ultra-Linear output stage was not the best approach. I discussed this with the best and smartest tube amplifier designers in the industry. Each person felt that using an output stage with a regulated screen supply voltage yielded the very finest results. My conversation with Stu Hegeman, (so long ago I was just a baby inventor) the designer of the Harmon Kardon Citation amplifiers, confirmed my experimental results. He explained that when using an ultra-linear tap for the screen grids during full signal drive, the screen voltage is unavoidably pushed so low that the maximum output current suffers substantially. Stu Hegeman, a genius, was right! I hope this helps if I haven't put you to sleep with my answer. Good luck, Bob Carver

Q: Hello Mr. Carver. I own Apogee Scintilla loudspeakers. I am interested in your amplifiers and love the sound of vacuum tubes. Every tube amplifier that i have tried with these speakers has been unable to drive them to an adequate volume level without distortion. Can you reassure me that these will work and, if so, how do they do it? Thanks.

A: Hi '113, Driving the Apogees is a matter of raw power as their impedance is about one ohm and their sensitivity is only about 72 dB SPL referred to one watt @ eight ohms. Pretty abysmal. But so what? They are among the most fantastic sounding speakers of all time. I remember first hearing them years ago, and knew I was in the presence of greatness! They were clearly designed by a person who loved music and wanted his speakers to sound as good as he knew how. And never mind the impedance or the sensitivity! He was a true artist, and that approach took courage because they were impossible to drive by normal amplifiers, and that fact alone limited his market tremendously. He was truly courageous. This amplifier has six powerful KT88 output tubes, and can easily deliver 27 peak amperes into a one ohm Apogee load. That's a peak power of over 700 watts! Not only that, but I own a pair of Apogees and have spent countless hours with this amp, together with the Apogees optimizing the whole system. I speak from first hand experience - fear not, these amps will drive your Apogees with aplomb. Good question, hope this helps, Bob Carver

Q: Bob: I notice you have said that these amps are the original prototypes after your (apparently) eventful meeting with Tim de Paravicini. However, you have sold other amplifiers here in the recent past. How do they differ from one another? Thanks a lot! Chris

A: Hi Chris, I just knew someone would ask this! The only difference is the output power because of my new output transformers. They sound the same except for that. Cosmetic differences are a change from bright bottom screws to shiny black ones, a shorter roll-bar for the tubes, and the chassis is infinitesimally (3/16 inch) longer to better allow the small tubes and volume control to fit. That's it. Great question, and thanks for asking, Bob Carver

Q: How can the tubes last for 50 years when most manufacturers recommend changing the tubes in their amps in 3 or so years? Dave

A: Hi Dave, That is a very good question! The answer is the DC restorer. Here's how. Most amps idle the output tubes at an average of 32 watts or so. Now the DC restorer allows the tubes to idle at about 9.75 watts. Since tube longevity is roughly proportional to power of the plate dissipation raised to the 2.3 power, we have 32 divided by 9.75 raised to the power of 2.3 = 15.4. Finally, 15.4 X 3 years = 46 years. I have also noticed that many console amplifiers have 50 year old tubes right here on eBay, and those tubes check out great. Great question, hope this helps, Bob Carver

Q: Hello Bob. Beautiful amplifiers. I doubt that I'll have the coin to win, but I do have a question: How do you get so much power from such a small amplifier? Am I missing something? Thanks.

A: Hi 'tss, Thank you, I think they are beautiful too. I spent a lot of time getting the color just right. I tried espresso brown, bright red, several other colors, and finally metallic burgundy cherry red. I liked that the best. As for the power, it was pretty easy actually - all we did was use a lot of output tubes, a transformer turns ratio of about 17:1, a robust high voltage power supply, and the vintage Silver Eagle KT88 easily did the rest. And it's NOT so small-each one weighs almost 45 lbs! Good question, thanks for asking, Bob Carver

Q: Hey Mr. Carver---how do you have such a nice finish on the first amps? They look so nice and new. Thanks

A: Hi 'k67, New finish. Fresh paint, new champagne escutcheons on the front and new champagne trim medallions on the transformer covers. There are some minor paint imperfections and some build-up around some of the small screws, but they are not visible to the naked eye at one foot. Or when riding past on a horse at a slow trot. Good question, Bob Carver

Q: Dear Mr. Carver, I found the last question and your answer about bi-amping with a combination of tube [high end] and solid state [low end] amplification to be very illuminating. As a solid state devotee for the past two decades--mainly Carver you will be pleased to learn but Bryston too!-- I feel re-assured by your statement that tube amplification does not necessarily deliver a superior audio experience. Am I going too far with this statement? I always warmed to the idea, in a tube-like way, that Carver "TFM" was a real technology, that solid state amps could deliver the warmth of tubes and then some. Don't get me wrong, I would dearly love to collect a pair of Reference Silver Seven Tube amps (as you will likely be aware, a pair recently sold on eBay for a shade under $19k). It is refreshing to hear, however, that solid state amps should not be discounted. I agree that tube amps are super cool -- I mean warm! Best, Marc + Maria + beagles Vancouver, BC

A: Hi 'oose, Absolutely! A great tube amp will sound wonderful, and a great solid state amp can sound wonderful as well. But they WILL sound different. A tube amp generally will yield a more enveloping soundstage and a greater front-to-back depth of field with tight imaging within that soundstage - a very romantic presentation. A well designed solid state amplifier will usually deliver a nice tight focus together with a greater up-front presentation. With these tube amps, a range of possibilities are possible, as the feedback switch and the bias adjustments allow the sound to be changed at will from very tube-like to almost solid state. This emerges naturally as a by-product of the DC restorer and the fact that the bias is "in the green" over a wide range of idling currents. Solid state amps are indeed not to be discounted - and thanks for your thoughtful and on the mark comments - they mean a lot to me. Warmest and best, Bob Carver.

Q: Bob. You sure got that "mad scientist" look on your face while winding that transformer! Thanks for sharing the pictures and your passion for audio excellence with us! John

A: Hi John, You think? Now that I look at it again, I see the only things missing are bugs in my teeth from the winding machine. The camera "stopped" the spokes - they are actually a blur. Bob Carver

Q: Hi Bob, hugh fan! In a bi-amping configuration, would you use these mono blocks the the upper or lower end? What are the pros and cons for this approach?

A: Hi '111, I would use these mono blocks for the high end and a solid state amp for the low end, unless you had two sets of these amplifiers. A vacuum tube amp by its intrinsic nature will yeild better bass because its output characteristic allows the signal to follow the impedance curve of the speaker system, delivering more voltage to the system within about an octive of its resonance frequency. This usually delivers a more satisfying low-end response. However, what normally happens in the real world is that vacuum tube amplifiers lack the raw power to effectively accomplish this; typically a solid state amp is more able to deliver the power needed and therefore works better. But NOT if we have four of these very powerful tube amps. Good question, Bob Carver

Q: Are the 180 watts rms pentode or triode?

A: Hi '4t, This is one of those simple questions with a very complex and extended answer. The answer here is pentode, but that's only the beginning of the story. Long, long ago, in the '30s and '40s the only way to build an amplifier without notch distortion was to build it class A. Many talented amplifier designers worked and worked on the this problem until at last a genius by the name of Williamson arrived and taught the world how to build a class AB output stage that was completely devoid of of notch distortion. This was late '40s - a breakthrough and the hi-fidelity industry took off. However, to work right, triodes were required which limited power efficiency - still, the leap in efficiency from class A to class AB was huge, completely overshadowing the fact that troides were not as power efficient as pentodes. Triodes were still needed to make notch distortion go away as the the art of output transformers had not yet been developed to their fullest. This was was because triodes had a characteristic known as "low output impedance" and could easily overcome the problems of leakage inductance in the output transformer. It took the genius Gordon Gow,a founder of McIntosh to teach us how to build a high efficiency class AB output stage WITHOUT notch distortion. Others followed suit at Marantz, Citation, Scott, Fisher and on and on. Today it is not difficult to build a class AB amplifier without notch distortion, thanks to the amazing pioneering work of those early guys. So - we see we went from triode class A to triode Class AB, and finally to pentode Class AB as the years trolled by. Often old ideas die hard, and to this day a false belief sometimes exists that triodes are still preferred in class A. It IS easier to design with triodes, but a superbly designed pentode stage will easily out-perform even a well designed triode stage. Any difference in sound is associated with the circuit itself, not the choice of pentode or triode. Thanks for the question, Bob Carver

Q: I own a Sunfire amp and the Current Source outputs are 1 ohm (I think). Curious to what the output impedance is for your new tube amps?

A: Hi '310, That is a very deep and important question - more than you might imagine. Let me explain. It is the details of the output impedance that convey so much of the musical romance we hear when listening to great amplifiers. The non-zero output impedance and its variation with frequency give rise to a large romantic and beautiful soundstage. It helps deliver deep front-to-back depth of field, together with sweet imaging within that extensive sound-field. It allows the amplifier to "listen" to what the room is doing acoustically; this room-amplifier interaction provides a sense of believable ambiance and acoustic space that is thoroughly realistic and quite enjoyable. All this for a number of technical reasons beyond the scope of my missive here. My latest thinking on source impedance is 1.30 ohms, my very most favorite number, and sure enough, Zout = 1.30 ohms for these amplifiers! One more thing, it may be changed from much lower than that to much higher by changing the idle current, and is read on the front meter. Great question, hope this helps and that I did not put you to sleep with my long answer. Thanks for asking, Bob Carver

Q: Wow two of the worlds best tube amp designers, one amp- must be AMAZING! I will bid for my Stax F81's, that need limitless juice to open up. I use a Luxman M6000 right now, but the promise of tubes like this on the Stax, I have to bid!

A: Hi 'att, Hey, I have only stood on the shoulders of the truly greats - Sid Smith, Frank McIntosh, Stu Hegeman, and foremost Tim de Paravicini. I'm lucky to be living now, and was able to rub shoulders with Tim and some of the other great amplifier designers. These amps DO have almost limitless juice to get any speaker to show its true self! Bid away, and if you should win and live within driving distance I'll deliver them myself. Bid away, happy bidding! Bob Carver

Q: Your amplifiers are beautiful. I love the dark red color, very classy. I have a pair of Apogees and I have been using a solid state amp and would like to switch to tubes. A friend of mine brought his tube amp over and it sounded great, but it couldn't drive them well. Do you think your amps would be able to drive them? Also, how is it possible that the tubes in your amps could last 50 years? I believe you, but it just seems to good to be true. Thank You, James.

A: Hi'tro, My mother taught me that if something seems too good to be true, it probably is. Forget everything thing your mother taught you about moderation - the tubes WILL last 50 years - here's why. First of all a good output tube that is operated well below its maximum dissipation (heat) level will last a long time, substantially longer than three or four years. They have been designed by our forefathers to do that. Take a look at all the vintage stereo amps listed on eBay - the ones from consoles - their output tubes are about 50 years old and usually check out fine. As for the small tubes, my own experience as a T.V. fixing man in my youth taught me that video pentodes and sync splitters seemed to last forever. They were not quite 50 years old of course, but close. It's the D.C. restorer that allows this extreme longevity, as it reduces the dissipation to about one fourth or one fifth normal practice. Longevity is calculated as related to the 2nd power of the dissipation ratio; 4^2 ~ 16. Finally, 16 X 3 = 48 years. I think the color is nice as well, it's a dark burgundy strawberry with a touch of metallic. Looks better in real life than in the pictures, if I may say so myself! As for driving your Apogees: If you have one ohm apogees, no problem - these amps can deliver over three hundred watts into one ohm. If you have four or eight ohm Apogees, driving them becomes super easy and a walk in the park for these mighty KT88's and powerful output transformers. I specifically designed them to be able to deliver lots of current by having a separate high current supply voltage source for the screen grids. Stu Hegeman (my hero) taught me how to do this long ago. Good questions. Bob Carver

Q: holy crap! are you really the bob carver?! if so you ROCK!!! anyways im a young audiophile vintage collector, are you on audiokarma.org? if so i want to add you to my friends list over there!!!!!! thanks! stereo rob.

A: Hi'hi fi, Holey Moley Rollers! I love your out-of-sight enthusiasm! I'll pinch myself to see if I'm really Bob Carver. Ouuuuccchh!! Yep, it's me, so count me in. Thanks, Bob Carver

Q: Hi Bob, Great pair of amps you have there. May I ask, (if it isn't an old family secret), what ingredient(s) you use to make the output transformers, that you are winding for these amps, that you are selling now, superior to the originals that you used to use? They certainly are beauties!!! Best of Regards, "jay"

A: Hi Jay, No secrets at all. I'm using oxygen free(well, almost oxygen free)copper wire, the hardest steel known to man, non flammable nitrate transformer varnish, and lots of love with tons of attention to winding geometry detail. Good question, Bob Carver
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
<<

TNRabbit

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 13301

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:41 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Q&A for the tube amp auction ending 9/25/10 for a record low price of $5200. This Q&A is a bit short owing to the fact that during half the auction Bob was attending Carverfest and was unable to respond to questions that came in though he did state he would respond to the questioners after the auction closed. We will not likely ever know any of that info because the auction page has closed. Enjoy!

Q: Hey Bob, I'm building an amp with some Dynaco output trannys. I want to use six tubes just like you have. Will the Dynaco A-450 work? How much power do you think will i gat out? Will they sound good? Thank you for your time, Win Sep-22-10
A: I am out of town and will not be home for about six days. I'll answer all questions then, though I won't be able to post them here as the auction will be over. But I'll still answer. In advance, thank you for writing in and asking such great questions. Bob Carver
Q: Why do tube amps sound so different from solid state amps? Sep-18-10
A: Hi'22 That's a great question. There are lots of reasons. Some mysterious and some not so mysterious. For today's answer, the not so mysterious ones. Before the auction closes, the mysterious ones. Here goes. 1)A tube amp can listen to the room - more on this later. 2)Its non-zero output impedance allows the spectral energy distribution to follow the impedance curve of the loadspeaker, allowing the soundstage to expand and deliciously envelope us. 3)I know this has not helped very much but I'm at Carverfest right now so more later. The question is extremely deep and complex and I promise to return to this important subject. Good luck and thanks for asking, Bob Carver
Q: Hi Bob, I am a long time fan of yours. I have always dreamed of owning a pair of your tube amps. I sadly cannot swing the high prices they command. I was wondering if it would be at all possible to get a schematic and parts list for this amp. I thank you for your time and effort. You are a legend. -Greg E-mail is Gregmacknass@netzero.com Sep-18-10
A: Hi Greg, Well there is no doubt that you will soon have one of these tube amps. I will be happy to send you a schematic. I don't have a parts list because it is in my head. The schematic will contain all of the information needed by a person skilled in the art of building amplifiers. When you are ready, contact me and I will send the output and power transformers. Please send me your email address. Good luck, warmest and best, Bob Carver
Q: Hi Bob, I received the two "Cherry 180s" from the previous auction yesterday and they're everything I could have hoped! Just wanted to let any prospective bidders know that these are even more beautiful in person and sound fantastic. Thank you! I do have one quick question though: I have a set of JBL-150As connected to the 8Ω lugs and want to simultaneously drive a set of Magnepan MG-IIs, which have an impedance rating of 6Ω. Since the combined impedance is ~3.4Ω, should I connect them both to the 4Ω lug, or separate them across the 4 & 8 do you think? Thanks again! Sep-16-10
A: Hi 'vert, You have made my day. Thanks. Hook both of them to the 8Ω tap, and let 'er rip! The reason, from a science perspective, is that the power curve is very broad and wide, encompassing from 2Ω through 16Ω ALL on the 8Ω tap! This allows the 8Ω tap to optimally drive a 3Ω load. Thanks for your accolade and your great question, Bob Carver
Q: I would guess that, given your experience with them, Alibaba might be run by forty theives ! Jim Sep-16-10
A: Hi Jim, You are right of course, Alibaba and the forty thieves! All I can say is it is very frustrating. eBay does a superb job of removing the fraudulent auctions as soon as they are brought to their attention. Bob Carver
Q: Bob are amps rating of 180 per channel conservative. Thanks Eddie! Sep-16-10
A: Hi '442, These amps... Hey I already answered this question! Read on. Bob Carver
Q: hello bob. i was curious to find out how these amplifiers are voiced as compared to your silver 7 and or silver 9 amplifiers? are they able to run some of your amazing plat speakers? Sep-16-10
A: Hi '307, These amps have my latest thinking regarding voicing. I designed the Silver series long ago, and the voicing remains state-of-the-art to this day. They have virtually unlimited power and sonic definition by any rational standard. Still, and just the same, I have changed the voicing subtlety with these amplifiers. Each has a different personality, and like our children, I love them all the same, even though each is different! Because these amps have a separate well regulated screen supply for the output tubes, and are pure pentode in design, they are capable of enormous output current substantially in excess of a normal tube amp design. Yes, they can drive the Amazings with aplomb! Hope my answer didn't put you to sleep, Bob Carver
Q: Bob are amps rating of 180 per channel conservative. Thanks Eddie! Sep-16-10
A: Hi Eddie, Here's the deal: After I changed the design of the output transformer, I found that the power increased to well over 240 watts rms; therefore, I changed the rating to 240 watts rms. However, when I talked to people I found that we all still called it the Cherry 180, even though it possessed 240 watts rms. Cherry 180 sounded better than eBay 240, so back to Cherry 180 I went. Even though it puts out more than 240 watts rms! Yes, it is conservatively rated at 180. Great question, Bob Carver
Q: Bob....I own 3 of your Lightstar amplifiers I use to power several sets of your Amazing Loudspeakers. Would these amplifiers deliver better sound than them and how? ray from CarverFest, north carolina Sep-16-10
A: Hi Ray from 'fest, Well, it's hard to say, maybe, and it depends. It is a matter of taste and the kind of sound we like best. A tube amp can listen to the room and deliver a sense of spaciousness and ambiance that solid state amplifiers cannot. On the flip side, we find a transistor amp can deliver detail, focus, and power that only the largest, most expensive tube amps can. A pair of these tube amps falls into this category. Hope this helps, Bob Carver
Q: Greetings Bob, After almost 20 years what made you decide to get back into designing and building tube amplifiers? If Carver Corp. had kept you on, do you think we would have seen more tube equipment from Carver, and what other items did you have in mind back then? Chris T. Sep-16-10
A: Hi 'i-o, I decided to get back in tubes because i love tubes. If Carver had kept me on, there is no doubt in my mind that i would have built more tube equipment. I had power amps, preamps, CD player, and active crossovers for speakers. Thanks for writing, Bob Carver
Q: Dear Mr. Carver, Sure love these KT88 ("Silver Three") amps! Unrelated to this auction. . . Did Stuart Hegeman's work on the Lowther Hegeman "Reproducer Speaker" influence your thinking in the development of the Amazing Loudspeaker? I have read that the Lowther PM4 driver paired unusually powerful magnets with an incredibly light cone for superior dynamic range and transparency of sound. Is there one particular speaker design that you used for reference purposes in the AL design process? Apogee perhaps? Regards, Marc + Maria + tri-colored lunch thieves (beagles) Vancouver, BC Sep-15-10
A: Hi Marc plus family, Well, I have studied Stu Hegeman's work to such an extreme that I feel that I'm part Stu and part me. He did use light cones though, and this, in part, is the formula for high efficiency. Super light cones will be weaker of course, so for high power we need more massive cones AND powerful magnets to overcome the added mass. This allows high power AND superb dynamics. As for my reference speaker - there is not one. I use many speakers, but there are a handful of designers that have influenced me a lot. Jon Dahlquist, Arnie Nudell (Infinity), Franco Serblin (Sonus Faber), and finally, the whole Apogee sereis of speakers.I have several of their respective designs in my laboratory, and all I can say is often I feel that I am in the presence of pure genius when I listen to their work. Bob Carver
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
<<

TNRabbit

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 13301

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:42 am

Re: Tuberific Q&A from one of Bob's eBay auctions

I have just located the Q&A from a very early Bob Carver tube monoblock auction, with date-stamped answers just as it would appear if the text from the auction had been copied. These appear to have been sold just a month prior to Carverfest 2008. I was aware I did not have Q&A from all auctions and still wonder if there is one more set of data as alluded at the link below. My memory fits with that assertion.

Thanks go to TomDac at the Martin Logan board. http://67.19.167.226/~tdacquis/forum/sh ... php?t=7106 He posted this info there a week after the auction closed and I post it here for preservation with the rest of the accumulated info.


Q: Hello Mr. Carver, kudos! Nice product! Do you think this amp design will ever be available for purchase on a limited scale, with modern day equivalent parts? Kind of a direct order scenario? Aug-19-08

A: Hi '-old, Thanks for the kudos! It's a new day and that helps makes my day! I have no plans, none at all, to build these amps with anything except vintage parts from my museum. Great question. Thanks for asking, Bob Carver

Q: Hi Bob. Could I get a copy of that DC circuit later? Email is r.gravlin@worldnet.att.net I have some spare Acrosound TO-330s that might work with it. Thanks for everything. Regards, Bob Gravlin Aug-19-08

A: Hi Bob, you carry a good name. And yes, no problem with the DC restorer. Bob Carver

Q: Hi, Tell me more about the output transformer What brand or general description ext. Very nice amp. Thanks Bernard Aug-19-08

A: Hi Bernard '081, This output transformer has a remarkable bandwith, and the reason I know how good it is, is that it was fairly easy to get the feedback around. Power response extends well beyond 20 kHz. As for the brand, I would tell you if I knew; I've had them in my stash for over 25 years, and for the life of me, I cannot remember what brand, no matter how hard I try, and they are unmarked. I've had them ever since my undergraduate days in college, always keeping them with me in the trunk of my car whenever I moved. I think I loved them more than my girlfriend. Good question, thanks for asking, Bob Carver

Q: Hi Bob, thanks for the explanation. I nearly get involved in a class A2 amp. I am glad I did not go for it. By the way Australia main voltage is 240VAC / 50Hz. Please let me know if I can bid with a 240v version. Tks Aug-19-08

A: HI, You are very welcome. And yes, this amp has a dual primary so it can be operated on either 120 volts or 240 volts. Thanks for asking, I forgot to mention it earlier. bob carver

Q: Hi Bob , wow what a wonderfull amp once again.....!!!..I have 2 questions..1..do you have a shop or retailer here in the Northwest..and 2..I just bought a used pair of your AL -III speakers with the cross overs..my question is how many watts per channel can they hold..I want to mono block my 2 Parasound HCA-1000,s (rated 400 watts each into 8 ohms,s)..I cannot find any where on the net a mannual for these speakers...Thanks for time... steve , Tacoma Aug-18-08

A: Hi Steve, Let me do a bit of research and get back to you, but please remind me next week to make sure I don't forget. Your missive sure brings back long ago memories! Thanks for writing, Bob Carver

Q: Hi Bob, Greetings from Canada. I have owned many of your pieces but unfortuneatley this lated work of art from you is beyond my reach. I do have a question to ask, if anyone would know it would be you. Ebay item # 140259226660 I just listed a pair of custom built KT88 Mono blocks (Not Bob Carver knock offs by no means) The builder as it turns out did not use the correct output transformers so there is distortion as you turn up the volume. I have had 2 people look at these and both have come to the same conclusion. I might be inclined to end my auction if I could get my hands on a pair of output trannies that would do the job correctly. With the people you know could you put me in touch with someone who would want to part with a pair of Old Stock. I am leary of using any of the new overseas stuff being offered online. Any trouble shooting or thoughts would be appreciated as well. Thanks for your time and any input. Aug-18-08

A: Hi 'forall, I love your handle. I'm afraid I hold a different view. It would be almost impossible that the output transformers are at fault. That's because the KT88 is the biggest output tube there is, and the reflected turns ratio of any rational transformer would not be such to over-load the tube. In the other direction, any distortion would actually go down. Plus, the chances of having TWO outputs be bad is almost zero. If you e-mail me your phone number after the auction is over, I'm pretty sure we can get to the bottom of this by going over it on the phone. We'll solve it. Looking forward to having a scientific discussion about amplifiers with you, Bob Carver.

Q: HI. I would like to know what class mode it is ? Push pull, triode, ultralinear and etc. and excuse me for being dumb. Do you ship to Perth Australia.. Thank you ,,, Hsrry Tan Aug-18-08

A: Hi'6059, I love questions like this 'cause I get to be a teacher again. Stay with me, sit back and enjoy the ride, and know that your question has a deep and technical answer. I begin. This amp is push-pull class AB. It is not ultra-linear, nor is it a class A triode. Class AB is called AB because the amp is like both sides of the same coin both, operating sometimes in class A and sometimes in class B. In the old days (vintage days), amplifier designers operated the output tubes with lots and lots of idle current in order to keep the output tubes in class A as long as possible. The solution was to run each tube at about 50 watts plate dissipation. Hot, hot hot!(Citation II power amp) with 33 watts being an average. Still too hot. Sometimes the plates would glow cherry red! And that was accepted; the amp ran in class A much of the time, keeping distortion well under one percent. Tubes were inexpensive back then so it didn't matter if they had a somewhat short life. For example, a 60 watt amp would stay in class A up to about 12 watts, then smoothly transition to class B for the rest of the way. If the tubes were operated with longer life in mind, class A would be good for about two watts. Running expensive output tubes that hot didn't seem like a good deal to me, so I invented the DC restorer to fix this problem once and for all. It allows class A operation up to about 108 watts rms, while at the same time keeping idle dissipation below 11 watts per tube. Back to Ultra-linear. I prefer that output tube screen grids be operated from a second, or regulated power supply than driven from an ultra-linear tap on the output transformer. Two reasons: when the output tube plate is pulled low by a powerful audio signal, the ultra- linear taps drive the screens so low that the output stage cannot deliver enough current to drive a difficult loudspeaker load. Operating the screens at a fix voltage competely fixes the problem, and avoids high voltage on them at idle. Safe!

Q: hey mr carver, will you talk me through putting them back together if i win, i doubt i will. lots of action from people who know a lot more then me. dad was a ee with bell labs for 38 years. watched him build his tube amps from scratch when i was 7 that was a 1961. they got trashed in a move in 73 . he passed this year would love to have them for just rememberance. sounded good too with the folded horns. i still see them hanging in concert/musical halls at the top corners of the stage. by the way, i have a 4.0t i love and all those 500t's they look as good as they sound. i love the old phaselinear s and the bestlooking blue meters on the mac's i know they are mostly for show but they look "cool" should i win, will you advise on a setup for the total system that i might be able to afford. i have a duak turntable and a denon table with sure and garrad pickups. i reacted without thought your name says it all. silver sevens were 19k each if i remember right. how do these compare? Aug-18-08

A: Hi tags, Your handle reminds me of an Al Cappy Lil' Abner character by the name of Joe Blfplk. Cannot be pronounced! Your adventures sure do take me down Memory Lane.My first amps were tube amps too. Had a pair of 50C5's, a 35W4, and a pair of 12AX7's. Anyway, I will help all I can. A BIG thanks for writing in and a big thanks for bidding. How do they compare? Well, that's sort of like asking a parent which child he or she likes best. Too hard that question! They both sound great, like life. Bob Carver

Q: Mr Bob... to get a mass product for your FUTURE... is it possible to ORDER to a factory to product the "NEW" Tubes..??? rather than CANIBALized the Old Amp...? > Go to CHINA for the IN-EXPENSIVE Labor ??? But Be FAIR TRADE PLEASE... they are HUMAN also...! I REALLY REALLY hope that you continue your DREAM MUSEUM with all those OLD ANTIQUE Amplifier. So the next Generation can learn from their heritages... Of course your Wonderful Creation will be the Master Piece in your original DREAM Museum. Please think about it ! I take a deep bow to honor the beatiful Mind and Beautiful Design for Both of You... WONDERFUL Team Work !!! BRAVO !!! MAJU TERUS ...!!! = Move forward ...!!! ThankUVmuch PEACE, moonear. a JAVAman in Minneapolis not the Englishman in New York. he... he.. he... Aug-18-08

A: Hi 'cat, Yes it is possible to go to China for the tubes and labor, but Tubular Joe is the best there is, and he lives right here in the rain-forest of the Northwest. YEA! AND he is having fun building them. As for the tubes - They are all NOS except for the Telefunken, and besides, I have lots to build with and plenty left over for my museum. Um mm... My Master Piece and Wonderful Creation in my Dream Museum! Ahhh... I like the way that sounds. Makes my day brighter. Thanks for writing, Bob Carver

Q: Beautiful MIND & Excellent Design > Simply Beauty... BRAVO !!! Aug-18-08

A: Hi 'cat, Wow. What a beautiful thing to say and what an original way to say it! Thank you 'cat from the bottom of my heart. Now I'm spooky, because if you look closely I'm levitating as I walk; my feet are not in touch with the ground. Thanks for writing in, Bob Carver

Q: mr bob You are known all over the world you are the greatest PLEASE MAKE MORE STUFF AND SIGN IT. ALSO TIM IS A NICE PARTNER FOR YOU BY THE WAY MY WIFE THINKS YOU ARE HANDSOME, IT MUST FEEL GOOD TO BE ABLE TO MAKE GREAT STEREO EQUIP AND BE HANDSOME ALSO. GOD BLESS BRUCE AND CARLA COALE FOREVERMUSIC414 .HOW DO YOU HAVE TIME TO WORK WITH ALL THESE EMAILS YOU GET,, YOU BROKE THE RECORD ON EBAY. IT IS NOT EVERYDAY AN AVERAGE PERSON CAN TALK TO THE BOSS STAY WELL,, I READ ALL YOUR EMAILS YOU HAVE A DEVOTED FOLLOWING FEW STEREO SHOPS WILL EVEN RETURN A CALL. PS I ENJOY MUSIC AND QUALITY EQUIPMENT. YOURS REALLY HOLDS IT VALUE,,,,,,, Aug-16-08

A: Hi '414, I feel lucky to have met Tim - he's a true genius and has been a great partner, even though he lives far away from me. Hey, if anyone says I'm handsome they can be my friend forever. Hi Carla, thanks! Keep on loving music you two. I manage to answer all my mail so far, but I do want to say thanks for writing in advance even if for some reason in the future I can't. Warmest rgards, Bob Carver

Q: Bob This may not be an appropriate place to ask this question but I've noticed in your recent sales that you are very cordial and enthusiastic about answering audio questions so I thought I'd give it a shot. Why did you chose the Yugo 6dj8s for the 490t and C-19 Carver gear? I have both models (and several of your amps) and enjoy them very much. Reason I'm asking is that I recently bought a 2nd SD/A-490t that had Amperex tubes installed. I tend to think the Yugos sound slightly better but can't find them too easily these days. I'm sure your ears are more critically tuned to tube listening than mine. Just wanted to know your thoughts and if there is a specific tube brand I should look for if I can't find a couple of Yugo 6dj8s for my 490t? I wont't be able to attend Carverfest or I would just wait and ask you in person. Good luck with your sale(s), they are impressive. Thanks Mark Aug-16-08

A: Hi Mark, Not to worry, I have a nice stash of vintage Yugo 6DJ8's in my museum. A few more than I need actually. I'll send you a pair free if you send me a reminder next week. Thank you, Bob Carver

Q: Mr Bob Carver , you old Mammiejammer , how are ya dude?? One of a kind , kick ass tube amp , partially designed by an Audio Icon.........Very Very Cool !!! Unfortunately , if I was to bid & win this exquisite work of art I'm afraid it would take up permanent residence in my ass , thanks to my very understanding wife : ) I know , its not a question. I really just wanted to say. Thanks for your proficient accomplishments in the audio field : ) Peace Brother Tom Aug-16-08

A: Hey Tom, You are making my day! Thanks for the thanks! I mean it. As for your permanent residence, think priorities, priorities, buy some flowers, make a bid, take a chance and let 'er rip. Bob Carver

Q: Hello, May I impose on you for a suggestion on what preamp would be a great match with your amp? I listen to vinyl and CD's. Best regards, Durs Aug-16-08

A: I would get a Citation I designed by Stu Hegeman or an EAR 864 designed by Tim de Pravicini. Both have magical phono stages: pure magic and the Citation has tone controls. The EAR is a great choice, with the worlds quietest phono stage, but no tone controls. Nice query, Bob Carver

Q: HI , SINCE THE BIDDING IS GOING TO GO WAY PAST MY CURRENT RESOURCES I'D LIKE TO ASK YOU TO CLARIFY SOMETHING FOR ME, I'M DISABLED FROM A 12,000 VOLT ELECTROCUTION AND RESULTING BRUSH FIRE SO MUSIC IS NOW MY PASSION MORE THAN EVER, I HAVE 2 NEWER MAC MC-275'S AND I'D LIKE TO KNOW WHAT IMPROVEMENTS I COULD MAKE TO THEM IF ANY, AND WHAT TUBES TO USE, I HEAR SO MUCH ABOUT WHAT DIFFERENT BRANDS ARE LIKE BUT IT'S SUCH A MYSTERY TO ME, ANY HELP IS VERY MUCH APPRECIATED, THANKS, ROB MCRAE IN COLORADO SPRINGS Aug-16-08

A: Hi Rob, 12,000 volts! Holy moley! I hope you are able to enjoy music as much as ever. As far as the 275's go, I would add lots of energy storage to the power supply. If you contact me after the auction, I'll send you some capacitors that will do the trick. Output tubes - brand new Shuguang output tubes are really great these days. Front -end tubes best to get used vintage RCA, GE, Tung-Sol, Sylvania, Raytheon or even NOS. Except they can be expensive. Thanks for writing, Bob Carver

Q: Hi Bob! Great pair of amps. Marantz fan here with a 7, 8B and 10B. Hey, I was wondering if you know the whereabouts of A.P. Van Meter with whom you used to work back in the Phase Linear days. Best regards, crooner Aug-16-08

A: Hi Crooner 7c, I don't have a seven or 8B, but I do have a 10B. I have lost touch with A.P.Van Meter over the years, but I'm pretty sure he is retired and still in the Seattle area. Try the phone book - if no A.P. contact me after the auction. Thanks for writing, Bob Carver

Q: Hi Bob, Very surprised to see you here on ebay. Do you think you could start making kits for those of us that remember Heathkit and Dynaco? The only time I get to solder is to repair something. I'm sure there are many in the hobby that feel as I do. Thanks, Alan A Aug-16-08

A: Hi Alan. Man, I would really love to make some kits, especially vintage vacuum tube ones. It's a great idea and would be good for me and fun for you. Sadly though, these amps are built out of parts from my museum, and if I used them for kits, they would be gone too soon. Maybe someday.... great idea! Bob Carver

Q: Hi, When are you guys going to turn your talents toward helping out us amateur and CB radio operators who need a great, multiband vintage-style RF linear amplifier with a filtered design that keeps our RF out of the neighbor's baby monitor, TV, and phone? Your workmanship is so neat and elegant, wow! Great job guys...everyone is so blown away by your amplifiers. Aug-15-08

A: Uhhh..... Also, thanks for the accolade, now we're truly blushing! Bob Carver

Q: Hi Bob, Can you tell me why there are (3) Red terminals on the back of each Amp & only (1) Black? Thanks, Lasareath Aug-15-08

A: Hi Lasareath, The black is common to the four red terminals; the color black is a standard to signify this. The four red terminals are different output transformer taps to allow different speaker impedances to be used. Taken Together, they range from one ohm to 32 ohms. Thanks for asking, Bob Carver

Q: Mr. Carver, My wife said if I bid on these amps I will be eating bologna for the rest of my life. Do you have any good recipes? Excellent amps, good to have you back on e-Bay! John Aug-14-08

A: Hi John, Priorities, priorities! Thanks you. Bob Carver

Q: Hey Bill, Is that a tuna fish sandwich? I really love the Vintage Iron hand made/signed concept. I sold amps like this 10-years ago, called them Vintage Iron or VI - made out of excellent Fisher (Todd NY) iron. Think I figured out your audio output diode rectified DC bias voltage feedback circuit to cook the tubes hotter with music playing, cooler when idling - need to try in my own VI amp and see how this works (oscillation?). Great idea offering genuine high caliber hand crafted amplifiers that are works of art, lifetime keepers that are signed by the masters. Rewarding for all involved. Sell on eBay in 30 years for $100k? Aug-13-08

A: Hi Paul, Cheese and bologna. Sounds like you had a lot of fun building amps too. And thanks for saying they are works of art! If you wish, I'll e-mail you a copy of the DC restorer circuit at the close of the auction. Please send me a reminder though. Bob Carver

Q: Hi Bob, 'was doing some late night eBay browsing when I ran across your auction. I'm 44 and started into audio at age 13 with Pink Floyd and a Dynakit. Anyway, I have some vintage B&K test equipment that you may be just the guy to help me move it. Please check out this eBay auction 250276768607 Thanks. Aug-13-08

A: Hi 'Ral, Will do. Bob Carver. Ha! I started at age 12.

Q: Hi Bob, I don't know if you're religous, but if you are, Jesus told me I was supposed to have these amps. thanks,(and God Bless) fred Aug-13-08

A: Hi Fred, I hope I can help - I'm saying my prayers for you right now. Jesus and I are with you. Good luck and may light shine on your bid. (With a little help from you of course.) Thanks for writing in, Bob Carver

Q: Hi Bob, pleasure to talk to you again. Last month you sold a pair of mono tube amp, using GE 6550 output tube and uses 12bh7 driver, same have 6AL5/5726 DC restorer. Identical on power bandwidth frequecy response of 2hz to 95khz with power output of 180watts each. The questions: Is the one you have now that uses KT88 design by you & Tim is this the same topologies/circuitry of what you have now, I thought you mentioned 6550 tube is the best according to Stu Hegeman. Question#2: My speaker is electrostatic, is this amp takes lower loads down to 2-1.5 ohms. Thanks, hope you make more amps like this & long live to you. Nappy Nagayo Aug-13-08

A: Hi Nappy, This amp is the same as the first one that was designed by Tim and me. Still, Stu Hegeman did indeed like 6550's better than KT88's, and that's why I used them when I built his phase inverter/driver circuit. This amp can use the 6550 or the KT88. It can easily drive an electrostatic even at 1.5 ohms; the output transformer is configured for one ohm and up.

Q: Hi Guys! Can the Neg Terminals be strapped together?, I have a pair of Polk Audio SRS 2's and they need Common Ground amps Thanks, Lasareath P.S. Bob, If you get the chance, check out my Polk Audio SRS 1.2TL's powered by two TFM-35X's on YouTube by searching for "Lasareath Bjork" Aug-13-08

A: Hi Lasareath, Yes. All you have to do is put the amps close together side-by-side, then connect the two negative terminals to each other with a short common wire. Viola! Bob Carver

Q: Two questions: #1 Will these be the only two made? #2. Do they have asymetrical holographic charge coupled magnetic activated sonic detectors? Aug-12-08

A: Hi Paul, Answer, question #1 - See an earlier question and answer regarding all my vintage amplifier parts. Answer, question #2 - Bob's my name, amps are my game, and if I invent it, I get to choose it's name. Thanks for the playful question, you made me laugh. Bob Carver

Q: I'll never forget the Stereophile review where you Bob Carver would take your solid state amp and modify it to sound exactly like a tube amp. I doubt it did. A friend of mine bought a 1.5T amp and at low volume it sounded fair which I assume was that Wima cap in the feedback loop but at higher volume it seemed to roll off the highs and lows and basically screamed a harsh sounding midrange. We modified the heck out of it but never got it sounding great. I'm sure this tube amp you have here sounds good. My present favorite amp is my old Audio Research D90 connected to my Acoustat electrostatics. Even though I didn't like your products I have alot of respect for you and what you tried to do. Aug-12-08

A: Hi 'dios, I came pretty close though - with a difference of three parts out of ten thousand. Read all about it!http://www.carveraudio.com/CarverChallenge. And besides, you are right about these tube amps - they are way better than the tube amps Stereophile used in The Challenge. Not to be compared. And besides, it was so long ago. Thanks 'dios - thought provoking comments, Bob Carver

Q: If i rob a bank and the notes are non sequential will you take cash,just kidding.I dont know what the hell half the parts do,but by God if thats not a work of art i dont know what is,BEAUTIFUL ,its nice to dream.Now compare that to class d,sorry couldnt resist. Aug-12-08

A: Hi Alleib, In this case I would say BEAUTIFUL is definitely in the eye of the beholder - it's good we all love amplifiers, but hey, I'll take it that way! Thanks for the kudo. As for class D, perhaps someday, just not yet. Bob Carver

Q: 100% W0W! Going through 12 pages of vintage amps, your amp is truly amazing! I will be placing a bid.... Regards. Central Park Ron NYC. Aug-12-08

A: Hi Ron, 12 pages of vintage amps? What 12 pages? Can you tell me? I would love to read more about vintage amps. Thanks for the confidence! Means a lot. Bob Carver

Q: Please advise the shipping cost to 38732. Will the item be packed in strong cartons? Thank you. Aug-12-08

A: Shipping will be approximately $117 dollars. We will double box each amplifier separately, as well as the vacuum tubes. Each unit will be wrapped in a special protective wrap, then put inside a plastic bag. Subsequently, bubble wrap and foam corner blocks will be used to hold it in place inside the first box. After that, an additional set of corner blocks for the outer, second box will be used. Safe and sound! Good question, Bob Carver

Q: Hay Bob and Tim Are these two going to be the only ones you do? Or do you have enough parts for more sets? or for that matter another design? Thanks RC Aug-11-08

A: Hi RC, I'm sitting here cross-legged in the midst of all my vintage parts. I have tubes, power transformers, output transformers, old time sockets, line cords, even vintage transformer covers all around me. Many parts, so little time. I really don't know when I'll build some more, but I just know I will. I couldn't stop building amplifiers even if I wanted to. As my museum gets smaller and smaller.

Q: NICE HAT BOB! Aug-11-08
A: Thanks Man. Nice bid!

Q: Aloha Gents, Is there any provision for upgrading the power supply cable for these beauties? Mahalo, Tiki Toenee Aug-11-08

A: Hi Tiki Toenee, Since IEC sockets were not yet invented during the vintage tube era, and this amp is built from my stash of vintage parts, it comes with a fully upgraded and dedicated supply cable. Bob Carver

Q: Sir, Just a note to say what an honor it is just to view the pics of such a wonderful looking and Im sure outstanding set of amps. More like works of art. Sure wish I had a blank check. Dan in Vegas Aug-11-08

A: Hi Dan, Thanks for taking the time to write, and for the encouraging comments. You are making my day. Bob Carver

Q: I am watching these awesome amps, I have to ask if this auction will run its full time? Thank you Aug-10-08

A: Hi '104, Yes, that's our intent and it certainly yields the most interesting and fun auction. mmmm "awesome". I like that. Thanks, Bob Carver

Q: Hi I like it! Please let me know the shipping fee to Los Angeles , CA 90061.Thanks Ho Aug-10-08

A: Hi '268, Glad you like it! Shipping is approximately $95 dollars.

Q: How does the sound of these amps compare to the Luxman 3045 or MC 40's? I think the Luxman sound is clear and pretty distinct while maintaining a good low end. I think the Mac sound is a bit muddier in the low end. I prefer the Luxman sound. I have a Luxman preamp to get the system started. Please do your best to answer this very subjective question. Roland 541-868-6512 cell Aug-09-08

A: Hi '8n8, The Luxman 3045 is superb but very rare, and it does sound absolutely exquisite! I love the delicacy of the 3045 over the MC-40. Always have, and of course these mono-block amplifiers carry a very similar lineage. Thanks for asking, Bob Carver
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
<<

TNRabbit

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 13301

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:44 am

Re: Tuberific Q&A from one of Bob's eBay auctions

The 9th pair of Bob's amps with meters sold for $5,722 on 9/6/10. The listing created some confusion over the power spec calling them 180 watt rated but with the now familiar text about Bob winding his own transformers on steel cores for a power spec of 240 watts. The latter should be true. As always, start from the bottom and read up. Enjoy!

Q: Hi Bob LOVE your work, I just got a good start in building tube amps, Love the smooth sound, I bought a old Bogen NTB-250 it is a solid state but it uses these big output trans. 125 each they use the same three wires that tube trans, will these work in a tube setup? Sorry this is not about this auction. Keep up the great work!!! Sep-04-10
A: Hi 'corners, I wish they would but they won't. The turns ratio is all wrong for coupling a tube amp to a set of speakers. However lots of vintage Bogens are tube amps and those transformers will work! Great question. Warmest and best, Bob Carver
Q: Hi Bob, sorry to bother again, but having read through the descriptions of several of your past auctions and their questions/answers, I haven't seen this question answered (admittedly, I probably just haven't looked hard enough). The pair currently for sale indicate that they're rated for 180 watts rms, whereas the last pair, although nearly identically described (same weight, frequency response, thd, etc.), were rated for 240. There are still some references in this auction to 240 (in the output transformer section), but elsewhere, the numbers have been changed to 180. Is something specifically different about this pair, or have you simply re-rated the design? Thanks! Sep-04-10
A: Hi introvert, I like your handle, it reminds me of me. Here is what happened - the new transformers allowed for a power output of over 240 watts, however when I started using the new name "eBay 240", I found that the name this amplifier had acquired all by itself was "Cherry 180". When I spoke the words "Cherry 180" it sounded much better to me than "eBay 240". More musical to my ears. The amplifiers are in fact identical, both clipping at approximately 245 watts rms. So to answer your question directly and in your words, I have simply re-rated the design. Hope this helps. Great question. Bob Carver
Q: Hey Bob, You know what I really love about your new amps? They're RED!!! Reminds me of my first Volkswagen! Think I'll spray paint my Phase Linear 4000 II to match... All seriousness aside, you are an audio GOD (will this help me in the auction?) All the best, Mike Casey Sep-04-10
A: Hi Mike, Thank you for your great comment, but I must say there is a smiling devil in me as well. And a GOD, audio or otherwise, will definitely help in this auction. I like RED too! Happy bidding. Warmest and best, Bob Carver
Q: Hi Bob, This is Tim from Wilmington,DE and was really depressed that your last auction of your SILVER SIX Amps went way out of my price range. But now I have another chance to own a set of your famous amps.I found your article on Output Transformers being the Heart and Soul of a good tube amp very enlightening and was wondering what you thought about PEERLESS Transformers since we all are not able to fabricate our own like you can.Do you feel they are one of the higher quality transformers or what would be some high end ones that you know of. It was great chatting with you again and hope to one day get to meet you and buy a set of your amps. I will keep in mind the fakes out there and do what I can to help you get rid of them.Well I will let you get back to winding and keep building the greatest amps ever made. Warmest regards, Timothy Michael McDowell-Wilmington, Delaware Sep-04-10
A: Hi Timothy, I know your feelings on missing out on a good thing, I have experienced that in my life as well, but there is always another chance. As for the Peerless transformers, they are indeed among the best. They're a fairly modern design constructed with low-loss steel and layer wound. The company was brought out long ago by Bogen and so the Bogen transformers are actually Peerless. Old beat-up Bogen amplifiers are available right here on eBay, sporting some of the best output transformers around. That's a secret. FAKES: I'm glad to report that I'm unable to locate any actual amplifier fakes; the fakery is associated with a direct copy of my auction, complete with my text and photographs of me. Thanks for writing,and thanks especially for keeping an eye out. Warmest and Best, Bob Carver
Q: Hi Bob, I see you fielded a question about the new KT-120 light bulbs. :>) I have heard they have more input capacitance, would that reduce your bandwidth, or is your driver stage able to blast right through it? Thanks! JAY Sep-03-10
A: Hi Jay, It is true the new KT-120's have more capacitance - they should have simply because they have bigger plates by half again. That means the inter-electrode capacitance (all else being equal) must also increase by the same amount. The good news is that it is so minuscule that the wires inside the amp possess more stray capacitance and totally dominate the kind that would hinder bandwidth.For example, any output transformer has way more, and since the driver stages are designed to overcome that reactance they would indeed 'blast right through'. We would not even be able to tell it was there. Excellent question, Bob Carver
Q: Mr. Carver - I have a number of your Carver TFM 40 solid state amps - bought them new 20 years or so ago. When one of them went dead, my high school son took it apart and you apparently told him to send it to you and you would fix it and tell him what was wrong. You fixed it - and inspired him to be an Electrical Engineer - he graduated with honors in EE in 2008. THANKS Now the question - I have a set of Infinity Reference IB towers with all the servo contols etc. I have been driving them with one TFM 40 for the base towers and one TFM 40 for the tweeter colums. Would it make sense to use these tube amps for the tweeter columns and then use the TFM 40's bridged for the bass so would have one tube amp on each tweeter column and one TFM 40 on each bass channel??? Thanks for your help!! Sep-02-10
A: Hi 'arres, With honors, WOW! That is great. I'm glad to have been an inspiration , but it was really YOU and he who should take all the credit for his achievements - well, maybe just a little for me. congratulations!(And welcome to my auction.) Your idea for driving the panels with these tube amps would be the cat's meow. As for the bass and the TFM 40's, I would not bridge them, rather hook them up in parallel with a one ohm resistor at the output of each amplifier channel and tie the two ends together (the ends NOT hooked to the amp channels), then that tied-together end goes to the woofers. This allows the amplifiers to follow the woofer impedance curve and will yield a very tuneful bass. Stay in touch and let me know how it all sounds. Of course the tweeter towers will be great - goes without saying. Bob Carver
Q: Hi Bob (I'm a little star struck to actually be asking you a question directly...), I've been looking for a more powerful tube amp to drive a set of 4ohm Magnepans and to replace the handful of ~50WPC 6L6 and EL34 driven vintage monoblocks I've acquired over the years. Having looked seriously though at several nice pairs of Mac 75s and Marantz 9s (which I still want before I die), I simply can't justify the extreme cost that vintage, marque brand tube gear is commanding currently when I'm convinced these amps will sound better and last longer (and are certainly more powerful). Anyway, I'm ready to bite, but I'd like to see a pic of the actual pair for sale this time if possible since I understand they're all slightly different. Alternately, since they're hand built one at a time, could you perhaps (if I win this one), keep the one you have now for the next auction and build me one in blue or black and ship when finished? Thank you! Sep-02-10
A: Hi 'ert, For the moment I'm out of chassis except red ones. I won't need any new ones for about three months (Tubular Joe builds about one a month). I just cannot bring myself to paint over the beautiful red finish these chassis have. Well, you know, Rembrandt did it to free up another canvas, so perhaps if he could do it so can I. Let me think about it. As for taking more pictures, I'm too lazy to set up my camera and my lights and my stage and do the download and I could go on and on. But it is okay, as all the amps look the same anyway and you would see no difference, none at all, even though each is lovingly built one at a time by me and Tubular Joe. Go for it! Warmest and best, Bob Carver
Q: Ola Senior Carver. Are these amps a "One Off" production or will more be avaiable in the future? I need to decide if I need to sell my car or house in order to buy these or if I can wait and save some money and then buy them. Regards, Andrew H Katy, Texas Sep-02-10
A: Hi '788, Don't sell your car or house or even your children - wait a bit - Tubular Joe can build about one amp per month on his kitchen table, so there should be many more. That is a very good question Andrew. Thanks for asking, Bob Carver
Q: HI Bob, I am interested in these blocks and Citation preamp. Would really love some silver 7s, really undecided on what to do. Should I spend the bucks for the 7s, also do you suggest one of you tube preamps to go with the 7s if I can find some. I guess I can get some 7ts if the others are too expensive, Whats your opinion. Look forward to hearing from you., Dave Sep-02-10
A: Silver Sevens are rare as hens teeth and very expensive. Sound-wise these are as good as Silver Sevens but don't have as many continuous watts; we could call them silver threes. As for the Citation one, it really is a wonderful preamp and I think impossible to do better. I just finished comparing (again) my Stu Hegeman designed Lafayette preamp with this Stu Hegeman designed Citation, and guess what? The Citation is better, not by much, but the cost-almost-no-object approach shows when compared to the price-point unit that Stu was no doubt constrained to when he designed the Lafayette. Thanks for writing and for joining my auction, Bob Carver
Q: Addendom to my last question, It is you, I looked you up. You revolutionized the industry with your power supplies. My friend replaced all his boat anchors with your new light weight Carver 1.5s etc, for his Martin W8 rig. I bought your Phase Linear 700s for my sound system in 1980. You sir are a legend. Sep-01-10
A: Hi 'tov again, I am? Thanks, Bob Carver
Q: Hi. Amazing amp. Are you perhaps the Carver of Carver Amplifiers that we used to get back in the 80s? Like, the pioneer of light weight high power amps? I can't remember the name of the technology back then, but it was ground breaking. Is that you? Thanks Sep-01-10
A: Hi 'tov, I am he. Yes it's me; just to make certain though I'll pinch myself - ouch - yes, it is I. Thanks for the sweet accolades, you have made my day, and it's still only early morning. Bob Carver
Q: Boy you guys know this stuff cold. I have a set of thirsty wilson MAXX and wonder what do you recommend amp wise for these beasts? If i order an amp how long does it take you and Tube to make it? Are there different models? Your story is super interesting to read... I'm a fan now! Sep-01-10
A: Hi rocket', I recommend THIS amp. If you win the auction, you will get it right away as we have it already built and ready to go. I only have one model, and here it is. Tubular Joe can build one in about three weeks once he gets started and gets on a roll. And yes, Tim is a true genius, no doubt. Thanks rocket', Bob Carver
Q: Hello Mr. Carver, Your Fraud Alert has scared me. I have just bought a vintage Bell Packard amp from Mr. Jordon Gerber, who claims to be your assistant. I haven't yet received the amp, despite the fact that I had fully paid it through PayPal... additionally, an identical amp has come back for sale in eBay, also by Mr. Gerber. I just wanted to check if you know Jordon Gerber, and whether he is a honest seller, or I should stop the sale in eBay, and avoid somebody else getting swindled. Thank you for your kind answer, and best regards Jaime Lorenzo Aug-31-10
A: Hi 'aii, Not to worry, Jordon Gerber is the real deal and his auction is 100% legitimate. Jordon is my very talented laboratory assistant, and we did indeed work on and refurbish your amplifier together. It just takes a long time to travel the seas and reach you. By the way, it sounds great - so good even I was surprised. Hang in there, and let me know when it arrives and how you like the way it sounds. You are wise to be cautious as we have discovered several frauds right here on eBay, as well as on some other sites. Stay in touch, Bob Carver
Q: Hello Bob, Great to see your still around making great stuff. I am a novice at tubes. I have Krell solid state separtates. My preamp is a KAV-280p. Would this be a satisfactory preamp for your amp? If not what would you recommend? Thanks Aug-29-10
A: Hi '33 fainting spells,Your Krell will work great - perfect in fact; the gain of this power amp is 30dB, and its input impedance is 100,000 ohms. The Krell is designed to run anything from 400 ohms to several megohms, and its gain is standardized for vintage as well as contemporary audio equipment. If you don't want to use your Krell preamp, then I recommend using a nice vintage unit like the Citation I. Thanks for writing, Bob Carver
Q: Hi Bob -- 6 output tubes; so three each side in parallel push-pull? And what are you using in the HV power supply? Tube fan, Steve K6PMF Aug-29-10
A: Hi Steve, Yes, I used three up, three down in push-pull parallel - I wanted plenty of output current so normally they would not even break a sweat. Each pair is good for 110 watts, so three are good for 330 watts. As for the power supply, you can see from the picture of the inside there are seven(!!) giant electrolytics and a pair of diodes for the the high voltage source. It runs at 660 volts D.C. under full load and the bias supply has its own diode rectifier and an additional pair of electrolytic condensers. The HV supply is a voltage doubler in which the screen grids of the output tubes are operated from the 330 volt portion of the power supply. I know this may seem like over-kill conspicuous consumption, but I wanted to know for sure that we run out of electricity, we will have gotten our fair share. Just kidding. Great question, hope this helps, Bob Carver
Q: Man those are beautiful -- absolutely beautiful. Best, Richard, WAYX radio Aug-28-10
A: Hi Richard, Wow! I love your comments. You can be my friend forever. I copied Stu Hegamon,Sol Marantz, and Frank McIntosh when it came to the appearance of this amplifier. What better shoulders to stand on? Bob Carver
Q: Bob, I (we) the entire audio crowd have been watching these works of art since the first one showed up and blew us all away. Can I like, sell you one my my kids, or at least have you take one as collateral while I save up the cash to get one? Just kidding of course. Ponder it O.K. Aug-28-10
A: Hi 49' I do take trade-ins. My friend who lives in a small house behind mine, has a cackle, a crooked walking stick, and just adores children. Thanks for your humor and most of all your passion. I'm pondering after all these years. Bob Carver
Q: Bob, i'd like to know if this system accepts newer KT-120 tubes. Thanks Aug-27-10
A: Hi 'hunter, The answer is yes - here's what happens when the KT-120's are installed. First, the loop gain increases slightly, thereby increasing the feedback a bit and so lowering the distortion ever so slightly. Next, the eight ohm power increases slightly - about 5 watts, resulting in clipping at 245 watts. Not much. Ahh, but at one or two ohms the power increases dramatically, and is just the ticket for Apogees with their wicked one and two ohm loads. The bias current will normally be increased a small amount, increasing the dissipation, but since the tubes are so huge (allowing them to throw off more heat per unit time), and the glass so heavy, they will actually run at a slightly lower temperature. Pop 'em in if you got 'em. Good question! Thanks for asking, Bob Carver
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
<<

TNRabbit

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 13301

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:45 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Sold for $7,700 on 7/29/10.

Q: Mine just arrived today! Got home from recording Elio Villafranca. Had to hook them up. WOW!!! Never heard my old stand in Castle Harlech's sound like this. Just HUGE so much control and weight with total delicacy in the quite points. The piano has the weight and tone I just left at the studio when Elio played the Fazioli!!! I am thrilled!! More later got to go listen! Jul-28-10
A: WOW! I'm glad they arrived safe and sound, and I gotta say, you have made my day! Thanks Robin, Bob Carver
Q: Hello Bob, I have a question for you about my Sunfire Classic tube preamplifier. My moving magnet phono section sounds terrible. It's real tinny sounding and has almost no low end. I had just got the unit used and the original owner only used moving coil cartridges. I replaced all the tubes (JAN Philips 6922 and Sovtek 12ax7LPS). Why does it sound like this? Jul-25-10
A: Hi 44' That's horibble! I designed that preamp to sound just the opposite of tinny with a warm and expansive soundstage. I don't know why it sounds horrible, but I do possess the technology to fix it and make it sound great. Is it under warranty? Oh never mind, just send it in to Rita's Vintage Audio and I'll fix it. Warmest and best, Bob Carver
Q: Those are some great looking amps, only a mad scientist could have designed those babies! I'm sure they sound as wonderful as they look! Now if only that mad scientist could design a tube amplifier that could sound almost as good for an unbelievable low price! An amp in kit form that was even more affordable would be stupendous, then some of us dummies that love electronics might learn something too! Excuse me while I go wipe the druel off my chin. john Jul-25-10
A: Hi John, I like your sense of style. Mad scientist, huh? Well, I looked at the pictures of me winding the transformers and sure enough, in one of them I look absolutely mad. In truth I was just happy that the transformers were working right. As for a good amp at an unbelievable low price, some of my old amp designs are for sale right here on eBay. They're not tubed though - transistor amps - they don't have my or Tim's latest thinking either. Now you have me drooling too - if you were laughing I would probably rolling over on the floor with the giggles. Thanks for the contagious emotions, Bob Carver
Q: Hello Bob, Had you seen this: http://www.apogeeacousti...pairsapogeeribbons.html Regards, David Jul-24-10
A: Hi David, Wow! I had not. Thanks a bunch - looks like I can get my Apogees fixed. Although they sound great, they will undoubtedly sound even better after these folks restore them for me. Thanks again - this really helps, Bob Carver
Q: Forgive me for being the man with a million questions, but I’m like this if I’m new to something. Being new to tubes I was looking at some on-line, mann there are a lot to choose from, and was wondering would the new Tung-Sol KT120 be okay in your amp or would it stress the transformer or maybe the other parts too greatly to be use in your amp? Tung-Sol KT120 is claiming more power being available with this type of tube and that it can fit right into any socket a KT88 can fit. If they are okay to be use would there be any adjustments that the owner needed to do or would it be a simple swapping-out of tubes? I know it might be best to have a piece of tube equipment before you start trying to tube roll :-D Jul-24-10
A: Hi again '310, As far as I can tell, Mike Mathews, the owner of Tung-Sol, has been trying to make a tube like this (KT-120) for about a decade. He finally succeeded and succeeded in spades! A tip of my hat to him! I purchased six to try out and found that they are indeed spectacular tubes. Four of them can do the job of six regular KT88's. The only thing I cannot tell is how long they will last, but I can tell how well they work, and they work as well as the best premium tube I've ever had. They can be dropped in most amps that use KT88's or 6550's. The power will not increase one whit though, as the power output is determined by the output transformer as well as the power supply voltage and current. In order to increase output power, the amp must be re-designed using a bigger power transformer, as well as for an output transformer with a different turns ratio. Still,tube swapping is fun, so enjoy it. No apologies necessary for being new to all this. Bob Carver
Q: I have a few questions on your output transformer design: You mention it is based on some old design, was it the Dyna A431? I had never heard of Adamantine steel, what is this core material and where do you get it from? I know in the past you have provided information on your designs, do you have any plans on sharing winding information on your transformer? Thanks. Jul-24-10
A: Hi '7543, This transformer was based on the teachings of many - David Hafler of Dynaco, Stu Hegeman, and many others. This unit was most heavily inspired by an unknown scientist who clearly designed output transformers for the United States (see description). Adamantine steel is the hardest steel known to man; it is similar to cold-rolled steel except it is heat treated and hardened as it leaves the rollers. My steel supplier made it for me. I'll be happy to share the winding geometry with you: contact me after the auction is over, and I'll send the drawings. When you build one and power it up for the first time, STAND BACK! Keep the creativity rolling! Bob Carver
Q: Are xlr connections an option on your amps? Are they a fully balanced design? I have a preamp with balanced connections and single ended connections. I prefer to use the balanced connections when possible. Jul-24-10
A: Hi '4t, No XLR connections on my amplifiers! I get great sound with a single ended vintage RCA input. The amplifier itself is fully balanced from input to output. Balanced connectors are useful for preventing hum and noise pickup during extra long runs, as in pro applications. As for home audio installations I think great sound comes from single ended vintage connections. Thanks for writing. All the Best, Bob Carver
Q: Dear Mr. Carver (& Zeus too!), Thanks as usual for being so generous with your time. We have some more queries about your (amazing) Carver Corp. days. 1. Thinking of your Carver solid state amplifiers, would you be so kind as to identify a few designs that you consider to be extra special from a personal point of view (possibly explaining why). 2. Are there any significant differences between the Silver Seven t and Nine t Mono Amplifiers? (Fyi, we own and love a pair of 7t's!) 3. Did Carver Corp. manufacture a tube pre-amp to work with the stupendous Silver Seven Vacuum Tube Amplifier? If so, what was its official model designation? Approx. how many were manufactured (if any)? 4. Can you share one of your "Eureka!" moments when you were designing/engineering? (Of course my wife & I love Dolby Digital (etc.), but we still consider Sonic Holography to be an audio triumph.) Best, Marc + Maria + beagles Vancouver, BC Jul-24-10
A: Hi Marc, Maria, and beagles, I will do my best here. Tube preamp: yes, Carver Corporation did make one, it was called the Silver One and sported about twenty vacuum tubes, primarily 12AX7's. I cannot remember how many were actually made, but it couldn't have been more then 100 units. As for my Eureka moment, most of my inventions have followed from a long felt need, OR something that I thought would be cool to invent. The Sonic Hologram generator was such an instrument and was the largest selling (unit volume) of my time at Carver. Great questions,hope this helps. Bob Carver
Q: Hello Mr. Carver, I hope you don't mind a question from a female fan of yours if the answer is no then here goes, at this point in time are you designing or do you have anything new and different apart from these amps that you will be building or are these going to be "The Last Frontier" in tube amps as there are most likely no other tube designers left out there that could top this pair. I enjoy and learn a lot by asking questions and the questions others ask you and your answers and comments. A Fan, Melissa Jul-24-10
A: Hi Melissa, Great question, and it has so much emotional content that I can't answer it right now. Since I have a day job, finding the time to invent new things is often difficult. I'm sort of thinking about an all vacuum tube preamp for us vinyl lovers. Cheers, Bob Carver
Q: Mr. Carver, Since Joe, THE master builder of tube amps has a new job, as you mentioned earlier in one of your answers/comments, will this affect your selling on e-bay? I hope it doesn't it's like a continuing Saga. "jay" Jul-24-10
A: Hi' music, Yes it's sad, but he got a new job, and we have to be happy for him. I'm going to try and get him to stay up late at night and build amplifiers. What can be more important, nes' pa? Wish us luck. Warmest and Best, Bob Carver
Q: I know this question keeps coming up in different forms all the time, but I think because it seems to truly fly in the face of normal belief. I’m a guy who leaves his gear on 24/7, except if I’m going to be away for days on end I power everything down. What formula are you using, or at least what is the hours-per-day/duration you are factoring in for a projected 50 year life span on these tubes. Bob I believe you, but I need some numbers and it’s next to impossible to convince anyone else of your claim. If I left these amps on 24/7 without eeeeever tuning them off, what can I expect the life to be? ...the 6 big ones and even the 4 small ones? And the audio quality of the tubes at that time? Now you look into that Crystal Ball and tell me damn it! Jul-23-10
A: Hi '310, I know 50 years seems too long, but it's not(barring a catastrophic failure). First the subjective component. When I was fixing television sets and Hi-Fi consoles for a living long ago, I noticed that some tubes seemed to last forever. 12BY7's, 6BQ5's, 6L6's, and on and on. Today we can buy vintage console amps on eBay that are 50 years old, and the tubes, especially the output tubes, check out fine. I have purchased many Telefunken 12AX7's on eBay (I know, I know, the possessive singular is followed by an apostrophe s, but this is for style); many of them are about 50 years old and test like new! Plus, they are about two dB quieter than even the best brand new tubes. Honest! Now by the numbers: I assume listening to music two and a half hours per day, five days per week. That's less than 33,000 hours in 50 years, a walk in the park for a great tube that is idled at only nine watts (not its specification of 42 watts). Look on eBay and you will find many, many vintage amps with 6V6's inside and they are OLD. And they work great! The secret is to operate them substantially below their maximum rating. Thanks to the DC restorer, these tube operate at 9 watts or so; we can touch the tubes without getting burned, though it will feel uncomfortable for sure! It is absolutely not necessary to leave these amps on continuously - I've designed them to warm up in the first few minutes and sound perfect after about seven minutes. If you left them on 24/7, the output tubes would last about four years is all. The small tubes probably six. Good question that needed some explanation. Hope this helps, Bob Carver
Q: Without having any kind of test equipment here at home with me, where would you set the gains on the Cherries to match-up with a Sunfire Signature CG? I ask because I would have the Cherries on the Mids/Highs and the Sunfire Sig. would move and cover the Bass duties on my IRS Betas? Would love, but not sure off of the top I could afford 4 Cherry amps to run my speakers :-) I’m considering also a new tube amp from Michael Elliot (formally of Counterpoint), but his is a hybrid tube design and since I have never done tubes I’m kinda leaning towards doing a full tube amp to see what the Tube sound is all about – decisions decisions . Jul-22-10
A: Hi '310 again, That's an easy question to answer because the gains are the same, exactly the same for both amps. 30 dB. That means the volume controls should be at full clockwise rotation (full up)for equal gain matching. If you want minus six dB, then set them at half mast for a 50% reduction. Or do it by ear. My favorite way. As for decisions, decisions, your instinct is on the mark regarding a hybrid; hybrids put the transistors in the output section, and it is the output section that counts most, so we should always put the tubes there - which means a full-blown tube amp as a practical matter. Thanks for writing, Bob Carver
Q: Hello, What are the dimensions of these beautiful looking amps? Jul-22-10
A: Hi '310, Oops!I should have that information in the auction somewhere, or at least a picture of a human model by its side for size perspective. Oh well, here are the numbers. 12 3/4 wide by 15 1/4 deep by 7 3/4 high. this includes about an inch in the back for binding posts and for the power switch handle, as well as about half an inch for the depth of the feet. Hope this helps, Bob Carver
Q: A couple of questions of mine and then I will let you get back to answering other questions. Hello Bob, A quick question do you find that each and every pair of amps that you build and sell are different and have a uniqueness/personality of their own or do they pretty well run true to the course? Thanks, J Jul-21-10
A: Hi J, That is a very good question. I actually have spent a lot of work and time to make certain that each amp sounds the same, exactly the same, as the one that was built before. There are about six small parts that are hand selected for optimum performance in each individual amp. Since each one is custom hand crafted, it requires more attention to detail to make sure that each amp is finished, performs, and sounds perfect. We(all of us) are fortunate to have Tubular Joe, the extreme perfectionist, building these amps. Bob Carver
Q: Hello Mr. Carver, I am one of the truly blessed people that you have helped with the building of their amps by generously sharing your schematics and information with us, there are just not very many master minds out there that would do what you do, let me stop here and say THANK YOU for doing that for me and others, as a result I have a system that only some dream about and was also once a dream of mine but is now a reality, a dream come true. Jay Jul-21-10
A: Enter your response here Hi 'music, You are very welcome, and I'm glad the amp you built sounds as good in real life as it did in your dreams. Whenever that happens to me, I have to pinch myself to see if it's true and if I'm awake. Thanks for writing, Bob Carver
Q: Will you be making more of these amps? Jul-20-10
A: Hi '27, Bob's my name, and amps are my game - I don't know if I could ever stop making amps even if I wanted to. Strictly speaking, Tubular Joe actually builds them in his kitchen whenever he has spare time, and he just got a new job (he's a sound man who puts up and takes down large systems for events in big auditoriums), so I don't know exactly just when he'll be able to build one next. But yes we will, hopefully sooner than later. Thanks for writing, warmest and best, Bob Carver
Q: I am now bi-amping with a mcintosh 275 and 225. How would your sound compare? The macs are over worked with the polk sda srs speakers I have. Jul-20-10
A: Hi '27, It's unusual to Bi-amp with two tube amps AND it is the very best way to go IF the tube amps have enough power. Here's why: For the bass, a tube amp is able to follow the increasing impedance rise as the frequency goes lower and lower. This characteristic allows the tube amp to deliver an increased voltage (about 50% more) into the woofer than it can at frequencies removed from from the speaker's bass resonance. Since virtually all woofers have a bass resonance, this yields a warmer rolling bass, a more powerful bass with greater articulation, and usually is more pleasant and fun to listen too. However, in the real world, most tube amps don't have the raw power or current ability (tube amps are voltage devices, whereas solid state amps are current devices) to drive a big woofer to to satisfying undistorted output levels. So by default this job is usually performed by a solid state amp, even though it's output voltage cannot follow the increase in low- end impedance at all. In other words, a tube amp is better than a transistor amp for the low end but ONLY if it can deliver the power and current. Most cannot, so the transistor amp wins by default. These tube amps of mine have lots of power and more to the point have been designed( by virtue of a separate screen supply power source and the D.C. restorer) to deliver 27 amperes of peak current, even more than most transistor amps. As for the mid-range and high-end, the virtues of a tube amp are well understood; your tube amp approach is right on the mark. How would it sound if you used my amp? I think it would sound much better. More drive voltage, more drive current, and finally that undefinable magic that sometimes only a very special tube amplifier can have. Thanks for writing, hope this helps, Bob Carver
Q: hey Bob: When are you going to put your Scintillas up for auction? I like the idea of an amp/speaker package! Jul-19-10
A: Hi'costa, Oh man, my Scintillas are very old and in dire need of a magic touch by someone. I have applied automobile rear window conductive paint on the ribbons to repair broken connections, the low frequency resonance of the main diaphragm has shifted so low with endless use and time that on piano music they often sound like a comb kazoo. I could go on and on, but you get the picture, nes' pa? So I'm going to keep them forever for myself; they sound so wonderful - I can forgive their buzzings, thumpings, cracklings as well as their outrageously power hungry diaphragms. Audio Nirvana is so hard to live with sometimes, but always worth it! Warmest and best, Bob Carver
TNRabbit
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From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
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TNRabbit

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(pair of) SILVER-7 TUBE AMPs

Posts: 13301

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:49 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Sold July 8, 2010, for a price of $7101.99, a price which seems much closer to the average than the wild price swings seen over the last few sold. The Q&A session was a bit more interesting as well with information coming about the amount of energy (in joules) each amp is capable of storing. Amazingly and typical for Bob, power is quite high and appears to rival even the vaunted Sunfire 300x2 and 600x2 amps. Read below to discover the truth for yourself.

Q: Would you be kind enough to entertain a visitor from Vancouver, British Columbia, Canada ? I sure would like to see and HEAR these amps. Vinyl is still me primary source of music. Jul-07-10
A: Hi 'ord, I would be delighted to. You are just over a two hour drive from my place, so bring your favorite vinyl - I have a special record cleaning machine. I'll be out of town until the middle of next week, so please e-mail me around Wednesday and we'll set a time. There are few things better or more fun. Warmest regards, Bob Carver
Q: …oh, and how many joules in each of these babies? Jul-06-10
A: Hi '310, For clarity, joules = energy. These amps have so much energy storage that even I feel a bit guilty of over-kill in the energy storage department. Call it conspicuous energy consumption, but at least when our planet's energy supply runs out, we'll know that (as tube amp aficionados) we will have gotten our fair share of it. Just kidding. These amps have energy storage that could only be dreamed about by vintage designers; they possess approximately 531 joules. Believe it or not! They do. Thanks for asking, Bob Carver
Q: I own a Sunfire amp and the Current Source outputs are 1 ohm (I think). Curious to what the output impedance is for your new tube amps? Jul-06-10
A: Hi '310, That is a very deep and important question - more than you might imagine. Let me explain. It is the details of the output impedance that convey so much of the musical romance we hear when listening to great amplifiers. The non-zero output impedance and its variation with frequency give rise to a large romantic and beautiful soundstage. It helps deliver deep front-to-back depth of field, together with sweet imaging within that extensive sound-field. It allows the amplifier to "listen" to what the room is doing acoustically; this room-amplifier interaction provides a sense of believable ambiance and acoustic space that is thoroughly realistic and quite enjoyable. All this for a number of technical reasons beyond the scope of my missive here. My latest thinking on source impedance is 1.30 ohms, my very most favorite number, and sure enough, Zout = 1.30 ohms for these amplifiers! One more thing, it may be changed from much lower than that to much higher by changing the idle current, and is read on the front meter. Great question, hope this helps and that I did not put you to sleep with my long answer. Thanks for asking, Bob Carver
Q: Hi Bob, Great pair of amps you have there. May I ask, (if it isn't an old family secret), what ingredient(s) you use to make the output transformers, that you are winding for these amps, that you are selling now, superior to the originals that you used to use? They certainly are beauties!!! Best of Regards, "jay" Jul-06-10
A: Hi Jay, No secrets at all. I'm using oxygen free(well, almost oxygen free)copper wire, the hardest steel known to man, non flammable nitrate transformer varnish, and lots of love with tons of attention to winding geometry detail. Good question, Bob Carver
Q: Bob: Wanted to send you a note to thank you for my monoblocks. I started buying and building amps (Dynakits)in 1966 and quickly became dissatisfied.I went through a lot of amps including several of the more famous and expensive products on the market. There was always a "bigger or better" available. I had finally deceided that the problem was me, not the amps. WELL, I received your beautiful Monoblocks in Feb. and I truly believe that this search is really over. I have never heard more beautiful, purer sound. From the sound stage to the crisp highs I am completely satisfied. I use them primarily for Phono (a Clearaudio Anniversary with tangential arm and xzy D4 cart) and they noticably upgraded the sound over my Macs and my 5803 Denon. I am trying different preamps and I have to tell you that the old Carver C1 that you reccomended that I try sounds better than the new Music Angel pre that Larry Z gave me to match them. Yor follow thru is appreciated and I will treasure them, Richard Jul-06-10
A: Hi Richard, Yea! Bob Carver
Q: Wow two of the worlds best tube amp designers, one amp- must be AMAZING! I will bid for my Stax F81's, that need limitless juice to open up. I use a Luxman M6000 right now, but the promise of tubes like this on the Stax, I have to bid! Jul-06-10
A: Hi 'att, Hey, I have only stood on the shoulders of the truly greats - Sid Smith, Frank McIntosh, Stu Hegeman, and foremost Tim de Paravicini. I'm lucky to be living now, and was able to rub shoulders with Tim and some of the other great amplifier designers. These amps DO have almost limitless juice to get any speaker to show its true self! Bid away, and if you should win and live within driving distance I'll deliver them myself. Bid away, happy bidding! Bob Carver
Q: I just wish I had the bucks Bob. I have a mint pair of Vortex Screens I stole for peanuts a few years ago but, as an underpayed aircraft painter, I've yet to get them the kind of juice they deserve. Sorry I can't afford 'em but I'm sure someone will. Maybe someday before the ol'ears give out. Glad to know your still making the world sound better. Jul-05-10
A: Hi'1914, Thanks for your nice words - there is no doubt in my mind that your ears will last a long time to come. When you are painting, I don't think the loud aircraft engine is running, right? So it cannot harm your ears. Lots of listening left! well, here we are, still in the arena after all these years! The Vortex Screens are quite efficient; they should do very well and present a beautiful sound-scape even without my amps. Enjoy the music, even after all these years! Bob Carver
Q: Silver Sevens, did you know how desired these have become? A friend of mine has a pristine pair of "amazings" and would love to add some sevens.Any chance of a retro? Jul-05-10
A: Hi taz154, Yeah I know. No chance of a retro by me - at least for now - but a good guy by the name of James may actually do it in the future. He is working on a pair right now with my blessing, and they are probably about a year away. In the meantime, a good alternative would be to use two of these amps per channel(four in all for both channels). That would make almost a seven, and with slightly more power. No doubt the Amazings would love it and sound stunning! Thanks for writing and for joining my auction, Bob Carver
Q: Your amplifiers are beautiful. I love the dark red color, very classy. I have a pair of Apogees and I have been using a solid state amp and would like to switch to tubes. A friend of mine brought his tube amp over and it sounded great, but it couldn't drive them well. Do you think your amps would be able to drive them? Also, how is it possible that the tubes in your amps could last 50 years? I believe you, but it just seems to good to be true. Thank You, James. Jul-04-10
A: Hi'tro, My mother taught me that if something seems too good to be true, it probably is. Forget everything thing your mother taught you about moderation - the tubes WILL last 50 years - here's why. First of all a good output tube that is operated well below its maximum dissipation (heat) level will last a long time, substantially longer than three or four years. They have been designed by our forefathers to do that. Take a look at all the vintage stereo amps listed on eBay - the ones from consoles - their output tubes are about 50 years old and usually check out fine. As for the small tubes, my own experience as a T.V. fixing man in my youth taught me that video pentodes and sync splitters seemed to last forever. They were not quite 50 years old of course, but close. It's the D.C. restorer that allows this extreme longevity, as it reduces the dissipation to about one fourth or one fifth normal practice. Longevity is calculated as related to the 2nd power of the dissipation ratio; 4^2 ~ 16. Finally, 16 X 3 = 48 years. I think the color is nice as well, it's a dark burgundy strawberry with a touch of metallic. Looks better in real life than in the pictures, if I may say so myself! As for driving your Apogees: If you have one ohm apogees, no problem - these amps can deliver over three hundred watts into one ohm. If you have four or eight ohm Apogees, driving them becomes super easy and a walk in the park for these mighty KT88's and powerful output transformers. I specifically designed them to be able to deliver lots of current by having a separate high current supply voltage source for the screen grids. Stu Hegeman (my hero) taught me how to do this long ago. Good questions. Bob Carver
Q: Hey Bob, I see your at it again. Don't ever stop. Although I could never afford your amps I sure love reading the Q&A's on your auctions. Toodles, Mr.M-500t aka the AVRiser Guy. Jul-04-10
A: Hi '16dc, Someone once said "never say never" - I don't remember who. Still,I'm honored that you enjoy the Q&A's, truly am. I enjoy meeting everybody, so COME ON all you vacuum tube amplifier aficionados - ask questions! Remember, the only dumb question is the one that is never asked. There is no bad question, none at all! Thanks my friend, Bob Carver
Q: Hey Bob, I have an older Carver CM-1090 with "Hologram". The output attnuation (volume)will at-times cause a partially grounded crackly muted RH output. Could I use the CM-1090 as a preamp to feed these Carver KT88s and is there any reason I would not want to drive my Dahlquist M-905 speakers with this much RMS power? They are fuse protected and the room is 12'W x 23'L. I listen across the width of the room and have enjoyed the Hologram focus point for many years now. Please advise / Thanks, Mack (VIP, being local to King CO, WA, where am I regarding any "Sales Tax"?) 253-850-5871 Jul-02-10
A: Hi 'ack, The output volume controls are easily fixed. About the only thing that goes wrong with them is that the pots sometimes get oxidized and dirty - short burst spray with de-oxit will almost certainly cure this problem. I used 200 watts per channel for many years without any trouble at all into my Dahlquist DQ-10s. The only thing I did wrong was rarely, occasionally bottom out the woofer on very low and loud bass notes. The fix was to turn down the volume a tad, then all was well. You should have no problems driving the 905s with this amp. They are quite robust. Hope this helps, Bob Carver
Q: Hello Bob, As a designer of test equipment and data collection systems, as well as being a vintage audio nut (both myself and my equipment are vintage), I must compliment you on a superb design both topside and below the deck. I would love to own a pair of these beauties, but my wife sets limits on my expenditures for toys, so I will continue to live with my pair of MC60s. What I cannot understand is why you are smiling while winding transformers. Best Regards, Dave Jul-02-10
A: Hi Dave, Well, thanks for saying such nice things about my design, top and below - I really think this IS my very best work. As for smiling, I must have been thinking about how truly wonderful this transformer was going to be when I finished winding, or perhaps it was simply lots of fun. I do enjoy building transformers, just the same, probably only a science nerd would find himself grinning from ear-to-ear while winding one. Again,thanks for writing, Bob Carver
Q: holy crap! are you really the bob carver?! if so you ROCK!!! anyways im a young audiophile vintage collector, are you on audiokarma.org? if so i want to add you to my friends list over there!!!!!! thanks! stereo rob. Jul-01-10
A: Hi'hi fi, Holey Moley Rollers! I love your out-of-sight enthusiasm! I'll pinch myself to see if I'm really Bob Carver. Ouuuuccchh!! Yep, it's me, so count me in. Thanks, Bob Carver
Q: Hi Mr Carver How are you? A few months ago you said that you have to revise the schematic. you told me in an email to remind you. I have some personal problems, I could not reply to you earlier. I would really like to have one copy of the schematic. I give you my word as a retired electronics technician, I will not sell, or distribute . it is for my personal use.Thanks very much..... Tazz Jul-01-10
A: Hi Tazz, No problem! Stay tuned because I'm going to update it and post it on this auction towards the end. I hope your personal problems have a happy ending, and no worries about not responding earlier. Use it and enjoy. Bob Carver
Q: Mr. Carver, if I told you that I could mount a modern PC inside either of the existing amps pictured with only flash memory for the operating system and easy-restore module, would you be interested in hearing how this could be done? I work as a Engineer for the Department of Defense and am currently in Baghdad, Iraq. My area of expertise: http://en.wikipedia.org/wiki/TEMPEST I can minimize RF emissions from modern PC's with very inexpensive shielding so as to not interfere with tubesound. I can build a very small (mini-ITX) PC with a restore function which has never been implemented by any manufacturer or government to date. It entails the use of Flash Memory for a pre-installed OS/software package. A complete restore of all software and operating system is possible within the normal boot time with the flip of a switch.(in seconds) http://en.wikipedia.org/...ee_Lossless_Audio_Codec The makes a PC elegant and uncomplicated with a perfect digital output/0 CPU RF emissions. Jul-01-10
A: Hi Triple seven, Your idea sounds super intriguing, and no doubt would be fun as well as scientifically interesting, however a problem immediately pops up in my head. The rules of this amp is it's a vintage design, using only parts and hardware available up to about 1960. That's not to say that thoroughly modern ideas and concepts cannot be used, still, PCs were not invented until the recent past, as it were. So . . . . until I make a non-vintage tube amp, the answer must be no in the sense of implementing it in these amp, but as a brain exercise, it would indeed be fun to know about. Stay in touch. Thanks for a great thought, Bob Carver
Q: Hello Mr Carver. I have seen a few of these amps on ebay over the last year and was wondering how do these amps compare to one of your T-modded Carver amps? What is the difference between a T-amp, and a real tube amp? Thaks for your time. Bill H. Jun-30-10
A: Hi 'O, Comparing the solid state T amps with these tube amps is very much like comparing our children. Each is truly individual and possesses a unique and different personality. The tube amp is more like a beautiful poem, whereas the solid state amp is more like a science and math person solving a quadratic differential equation. Magic in both! Somehow, on one hand, I dont't feel I answered the question, but I did! Thanks for joining my auction, Bob Carver
Q: Bob - Nice amps! Very similar to some you had before. I like the OPT! I'm still working with the medium power stuff, 50-60 watts/channel. Have you run across the new Tung-Sol (EH) KT120s? Thanks, Tim Smith Jun-30-10
A: Hi '95, There are few things in life more rewarding than working with and building amplifiers. Even winding the OPT (output transformer) is lots of fun. As for the Tung-Sol KT120s, I purchased six of them and put them through their paces, and I can honestly say that they are great power output tubes - they do everything right. Mike Mathews and his colleagues did a great job designing these tubes; I think he has been trying for at least a decade to come up with a tube like this. He finally did it! Keep on building! Bob Carver
Q: Is it possible to have these amplifiers wired for 220v? Do you have an idea what shipping to London England might cost? Looking forward to your reply, Fritz Jun-29-10
A: Hi Fritz, You can have them wired any way you would like for your country or for your power. Shipping to London is U.S. $526 dollars, plus or minus. That is the cost delivered to the base of Big Ben, your address may be a bit more or less, still that's pretty close. Thanks for writing, Bob Carver
Q: What is the power consumption of these amps, and what kind of heat will they be putting off? Chris Jun-29-10
A: Hi Chris, Well, let's see. At idle. KT88 filaments consume 10 watts each. Times six = 60 watts. KT88 plate and screen ~ 9.25 watts X 6 = 56 watts. Small tubes about 8 watts total. Fudge factor of perhaps 15 watts - that's 60 + 56 + 15 = 131 watts, thanks to the DC restorer. Not much for a tube amp; it's so little we can actually hold on to an output tube and not get burned - it's extremely uncomfortable though. The heat it gives off is distributed over the entire chassis, so that at any one spot, the heat is small enough so we can hold or touch it anywhere. Great question, Bob Carver
Q: Greetings again Mr. Carver: I have wondered for quite some time whether you worked with an industrial designer in your Carver Corp. days to create the bespoke industrial Carver "look." One example, I find the Silver Seven t's to be visually stunning (okay, not as stunning as the gorgeous tube Sevens!). I love the fact that they are so uncompromisingly different from any other solid state amplifier (internally as well). My wife thinks they would look at home in a nuclear missile silo (!) but admits too that they produce gorgeous music when effortlessly driving our vintage KEF Reference Series speakers. I wonder if you would care to comment on the design of the Sevens in particular and how that came about. I would guess that the solid state version was intentionally derivative of the reference tube design. Nevertheless, who created the key design concepts in the first place? You?! Again??!! (o; Best, Marc + Maria + beagles Vancouver, BC Jun-29-10
A:
Hi guys, Regarding aesthetic appearance: All of my Sunfire designs and most, but not all, of my Carver designs were done by me having as a beginning a rough sketch on a piece of paper inside my notebook. The Silver Seven design emerged as form-follows-function. I copied Stu Hegeman's design of the Citation II; transformers in the back, power tubes in front, a champagne escutcheon on the front. A separate power supply was mandated because otherwise it would have been all but impossible to lift. As for the sonics - it was the "Carver Challenge" of long ago that led me to build the best tube amplifier ever built. At least from my humble perspective. Thanks for the kind words. You have definitely made my day! Bob Carver

Q: Hi will amps operate on 220 volts? We also have 50 Hertz. Je vous remercie de votre réponse. Jun-28-10
A: Hi new friend, I can tell your English is far better than my French. These amps have been designed to operate on 220/240/110/120 Volts AC and 50/60 Hz. It's a standard transformer with "split" windings and is easily wired for 120 or 240, however the change must be performed by experienced and qualified personnel. I can send it to you with any voltage you want. Hope this helps, Bob Carver
Q: I've heard of these scams, and I wondered if you wouldn't mind telling us something only you would know to verify your identity. We already know your dog's name. Thanks Jun-28-10
A: Hi 'oe, Hmmm,let me think. I'll answer a science question since you already know my dog Zeus and his name. Were you aware that the average idle current at 715 volts is .080 amps combined for all six tubes? See it's me! You make me smile. Warmest and best, Bob Carver
Q: Greetings Mr. Carver. I've been looking at your beautiful amps, and would like to know if I could audition them. I live in Portland, Oregon, so I'm pretty close by. Thanks very much. Jun-28-10
A: Hi'57t, Portland is just a stone's throw away and a beautiful drive up the coast with the ocean on the left and cliffs on the right. I would be more than happy for you to visit; we could listen into the wee hours. Just bring your favorite vinyl. Or CDs. See you soon, Bob Carver
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From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

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(pair of) SILVER-7 TUBE AMPs

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Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:51 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Sold for just $5655.55 on June 19, 2010; a price near the bottom end of all the tube amps so far. This time they are said to be his prototypes with his own self-wound transformers in place of the vintage iron. Again, the newly wound transformers output power is bumped from 180 watts to 240 watts at 8R.

Q: I have often read that an Ultra linear output tube connectin is best for class AB amps. Yur amps are not Ultra linear, what is your opinion on this and what is the difference? Thanks for your time, Tim Jun-13-10
A: Hi 't42, Long ago when I first started desinging tube amps I read the same literature promoting this same idea. However, an important series of converging experiments taught me that an Ultra-Linear output stage was not the best approach. I discussed this with the best and smartest tube amplifier designers in the industry. Each person felt that using an output stage with a regulated screen supply voltage yielded the very finest results. My conversation with Stu Hegeman (so long ago I was just a baby inventor), the designer of the Harmon Kardon Citation amplifiers, confirmed my experimental results. He explained that when using an ultra-linear tap for the screen grids during full signal drive, the screen voltage is unavoidably pushed so low that the maximum output current suffers substantially. Stu Hegeman, a genius, was right! I hope this helps if I haven't put you to sleep with my answer. Good luck, Bob Carver
Q: Hello, Mr.Carver, I am very interested in these amplifiers. I'm primarily a two channel person and own a pair of Infinity Betas, the original units with a separate external amplifier. These speakers are difficult to drive. Will your amplifier be able to drive them so that I can listen to them at loud but realistic sounds? Thank you for your time, Andrew. Jun-13-10
A: Hi Andrew, The Infinity Betas are truly great sounding speakers, albeit somewhat difficult to drive. Fortunately they have a separate, dedicated amplifier for the woofers. This allows all of the power from the main driving amplifier to be used more effectively because it doesn't have to operate the woofers. That being the case, this tube amplifier can deliver as much power as anyone could rationally use or need into your Betas. Except for truly crazy audiophiles like me. Just kidding. Great question, thanks for joining my auction, Bob Carver.
Q: Hey Bob, cool amps! i intent to win and have these set up in my house by my wife's birthday! She's a long time fan of yours. My question is can you autograph it saying "to my loving wife, Happy Birthday always"? Thanks, Gary Jun-12-10
A: Hi Gary, I'm glad you want to give your wife a nice birthday present. I'm honored, but I have to ask is this similar to a young boy buying his mother a football for Mother's Day? I'm just happy she's a true audiophile. The answer is a resounding YES of course I can autograph anything you wish! Warmest regards Bob Carver
Q: Hi Bob, those are some beautiful amps, and works of art! If I win the bid, can you put on an IEC type plug so that I could use my own line cord? Thanks,L8tr. Jun-12-10
A: Hi L8tr, ummmmm, I think that means Later, right? Anyway, the simple answer to your question is NO. Here's why; first of all the hole in the chassis will not accomadate it unless we hand file a larger hole which has to be square and might chip the paint. The scientific reason is that I do not believe in IEC chords. The connections are designed to be universal and they come loose too often. I speak from first hand experience, and besides I get better sound from these amps by using a vintage hard-wired AC line connection. Good question, thanks for asking, Bob Carver
Q: Hi Bob, Were you a little hesitant to sell your prototype? Just think one of a kind, A classic to say the least, there has never been a pair of amps like these before nor will there ever be another like this pair again? To me it most likely be like giving up and old friend, however, it is great of you to give some blessed person or persons the opportunity to have and hold, (not literally, much too heavy), for fifty year or more. Did you put your all in the building of these guys? best of the best? How long were they in the making? Just curious as to your plans for the original output transformers that you had used in them, you say you are using two of your latest masterpieces in them now, Might the the destiny of the originals be in The Bob Carver Museum? That brings me up to my last question, will the museum be in the "Old Sunfire Building"? I have been wondering about that. Thanks for allowing my twenty questions. "jay" Jun-12-10
A: Hi Jay, Wow! Here goes, in no particular order: I have indeed put my all into these amps; I've been designing them in my head since 1986, about 24 years. Still, and just the same, I am not at all hesitant about selling my protypes as I think they can be a powerful force for good by making music for the world to hear. The output transformers that were originally in them were robbed long ago in order to build these current amps, so their ultimate destiny cannot be my museum. Not to worry, I did save one transformer for the museum. I am not sure where the museum is going to be. The old Sunfire building is way too big for my modest vintage audio museum. Whew! I hope I answered all 20 questions. Thanks for the great questions, Bob Carver.
Q: Bob- you are the man!! I have never enjoyed reading the "Ask a question" as I have here. Off Subject, I am a big fan, have been since the 70s. My question: will my M 0.5t sufficently push my recently acquired ALS-IIIs. These are beautiful speakers. Good luck with these amps but I am hopelessly trapped in the past. Walt Jun-11-10
A: Hi'nic, I am glad to find another soul lost in the past. Since I was old when Atlantis sank, I too am hopelessly trapped in the past. As for the M-0.5t, from a sound quality point of view it will work great. As for having enough power to drive the speakers to a satisfying loudness level, you must determine that for yourself; if you are passionate and crazy (like me)after all these years and want to have Beethoven proud, especially when we turn on the opening chords of Ode to Joy, you MAY have to get more power. Your choice. No right or wrong answer here. Good question. Thanks for asking and for joining my auction, Bob Carver
Q: Hi, Will a bank or money order work for payment if I win? Thanks Bert Jun-11-10
A: Hi'63, With a name like that you sound like a special agent! A bank or money order will absolutely work for payment. Bob's my name, amps are my game, and I accept any rational form of payment, send all you've got. Just kidding. Thanks for asking, Bob Carver
Q: No question for you just a link for you. Carver Amazing LoudSpeaker Original Platinum Edition http://chicago.craigslis.../chc/ele/1785459378.html Jun-11-10
A: Hi '154, Wow!! That is really cool. I will look at it this afternoon. Regards, Bob Carver
Q: Hello Mr. Carver, I own a Margules amplifier, and I like how it sounds and its autobias feature. I imagine that your amplifiers are way ahead of mine in terms of power output and quality sound, but I have two questions: does your amplifiers are autobias, or I need perfect matched tubes? does your amps can be work in triode mode or only ultralinear?. For your attention, thank you very much. Jun-11-10
A: Hello '77, Wow if you had another number you would sound like an Boeing airplane. No, these amps do not require matched tubes, as the DC restorer eliminates the need. These amps operate in pure pentode mode, with each tube having a separate voltage supply for its screen, yielding the very best sound. Warmest and best, Bob Carver
Q: Hey Bob, your knowledge of audio is amazing and your attitude with which you answer folk’s questions, with such gitty zeal, is funny and rewarding. I can’t afford these amps at this juncture in life, but I do own a “tube-like” amp; I own a Sunfire. Thinking of getting another one, used, but was wondering what your thoughts were on Hor. and Ver. bi-amping? I keep hearing Ver. is the way to go and I gather I’ll try both when I get the other amplifier, but still desired your feedback on the subject. Jun-11-10
A: Hi'310, I like your thoughts about my amazing audio knowledge and attitude - you're making my day! More please!! I'm taking a bow, but must be careful not to hurt my back. Most speakers were designed by their designers to be operated from a single full range source. My preference is to honor the designers intent, therefore I prefer and believe the best sound is had by wiring the high frequency drivers and low frequency drivers to the same source, using a separate set of wires for each. An alternate way of doing this, provided we have a tube amp and a transitor amp, it may work best if the high frequency drivers are wired to the tube amp and the base drivers are wired to the transitor amp. Your choice based on careful listening. Thanks for writing, Bob Carver
Q: Hello Mr. Carver. I own Apogee Scintilla loudspeakers. I am interested in your amplifiers and love the sound of vacuum tubes. Every tube amplifier that i have tried with these speakers has been unable to drive them to an adequate volume level without distortion. Can you reassure me that these will work and, if so, how do they do it? Thanks. Jun-09-10
A: Hi '113, Driving the Apogees is a matter of raw power as their impedance is about one ohm and their sensitivity is only about 72 dB SPL referred to one watt @ eight ohms. Pretty abysmal. But so what? They are among the most fantastic sounding speakers of all time. I remember first hearing them years ago, and knew I was in the presence of greatness! They were clearly designed by a person who loved music and wanted his speakers to sound as good as he knew how. And never mind the impedance or the sensitivity! He was a true artist, and that approach took courage because they were impossible to drive by normal amplifiers, and that fact alone limited his market tremendously. He was truly courageous. This amplifier has six powerful KT88 output tubes, and can easily deliver 27 peak amperes into a one ohm Apogee load. That's a peak power of over 700 watts! Not only that, but I own a pair of Apogees and have spent countless hours with this amp, together with the Apogees optimizing the whole system. I speak from first hand experience - fear not, these amps will drive your Apogees with aplomb. Good question, hope this helps, Bob Carver
Q: Would you ship to Hong Kong? I will pay by PayPal. What is the shipping cost? Jun-09-10
A: Hi 'trad, Yes I will happily ship to Hong Kong, and the cost is about $185 dollars each, or $370 for both. PayPal is good. Thanks for joining in, Bob Carver
Q: Bob: I notice you have said that these amps are the original prototypes after your (apparently) eventful meeting with Tim de Paravicini. However, you have sold other amplifiers here in the recent past. How do they differ from one another? Thanks a lot! Chris Jun-09-10
A: Hi Chris, I just knew someone would ask this! The only difference is the output power because of my new output transformers. They sound the same except for that. Cosmetic differences are a change from bright bottom screws to shiny black ones, a shorter roll-bar for the tubes, and the chassis is infinitesimally (3/16 inch) longer to better allow the small tubes and volume control to fit. That's it. Great question, and thanks for asking, Bob Carver
Q: Hi, Bob. Apparently some would-be scammers have grabbed hold of your items during some of the past auctions and have tried to rip off honest bidders using your pictures and description. To separate the REAL Bob Carver from the scammers, what's your dog's name? Thanks! Jun-09-10
A: Hi 'qn, It is frustrating to see this happen - eBay has tried hard to keep the scammers shut down, and have pulled those schemers off line as soon as they (eBay) knew about it. Please do not send them any money, no matter what they promise, as you will almost certainly lose it all! They are easy to identify, at least on eBay, as they will not answer any QUESTIONS through eBay, even though they let you send MONEY. My dog's name is Zeus. Bid without fear, Bob Carver
Q: How can the tubes last for 50 years when most manufacturers recommend changing the tubes in their amps in 3 or so years? Dave Jun-09-10
A: Hi Dave, That is a very good question! The answer is the DC restorer. Here's how. Most amps idle the output tubes at an average of 32 watts or so. Now the DC restorer allows the tubes to idle at about 9.75 watts. Since tube longevity is roughly proportional to power of the plate dissipation raised to the 2.3 power, we have 32 divided by 9.75 raised to the power of 2.3 = 15.4. Finally, 15.4 X 3 years = 46 years. I have also noticed that many console amplifiers have 50 year old tubes right here on eBay, and those tubes check out great. Great question, hope this helps, Bob Carver
Q: We live in Germany. I love your amplifiers. My father has been a fan of yours for many years. His birthday is next month. How much would it cost to send these amplifiers to Munich? Danke! Detlef Jun-09-10
A: Hi Detlef, I can't sing happy birthday in German, but I wish your father a happy birthday sung in English. To the tune of Clair de Lune....Happy birthday to you, happy birthday to you, - I could go on and on. All the way to Munich, Germany is about $240 dollars each, plus or minus. Thanks for asking, Bob Carver
Q: Hello Bob. Beautiful amplifiers. I doubt that I'll have the coin to win, but I do have a question: How do you get so much power from such a small amplifier? Am I missing something? Thanks. Jun-09-10
A: Hi 'tss, Thank you, I think they are beautiful too. I spent a lot of time getting the color just right. I tried espresso brown, bright red, several other colors, and finally metallic burgundy cherry red. I liked that the best. As for the power, it was pretty easy actually - all we did was use a lot of output tubes, a transformer turns ratio of about 17:1, a robust high voltage power supply, and the vintage Silver Eagle KT88 easily did the rest. And it's NOT so small-each one weighs almost 45 lbs! Good question, thanks for asking, Bob Carver
Q: Do you ship to Italy? How much cost? Jun-09-10
A: Hi 'anb, Yes indeed I do ship to Italy. I can do that because airplanes and ships and trucks arrive in Rome every day. No problem, and the cost is approximately $210 dollars per amplifier. Thanks for asking, Bob Carver
Q: If you were to send me a dummie case, that is no transformers parts inside, just the finished case with tubes, I'd be glad to photograph it for you professionally for free and return it. Check me out at StudioNOVAimages dot com. Great amps by the way. Best Regards, Tony Nova Jun-09-10
A: Hi Tony, I can't sing, I can't play baseball, I can't dance and I surely cannot handle a camera well. I can design amps though. You are ON! Thank you for your offer - I will send you a case soon after this auction is over. Thank you thank you! Bob Carver bob.sunfire@gmail.com
Q: Hi how much do they sell for If a guy whated to just buy him self a set and skip the biding part of ebay ? Jun-09-10
A: Hi '008, Ummm, good question, let's see, there is paint, the chassis, the vintage tubes, covers and tube sockets, plus line cords and lots and lots of time. It takes me a full day just to wind a pair output transformers - it's a good thing I enjoy building amps so much! I cannot say, how about making me an offer we can't refuse. Seriously. As for this auction, it must run its course. Thanks for writing and joining in, Bob Carver
Q: Hey Mr. Carver---how do you have such a nice finish on the first amps? They look so nice and new. Thanks Jun-18-10
A: Hi 'k67, New finish. Fresh paint, new champagne escutcheons on the front and new champagne trim medallions on the transformer covers. There are some minor paint imperfections and some build-up around some of the small screws, but they are not visible to the naked eye at one foot. Or when riding past on a horse at a slow trot. Good question, Bob Carver
Q: Dear Bob, I was wondering, after all the years of designing SS amps, you have an affinity for tubed amps, to say the least! When did you realize that you wanted to use tubes? I was also wondering if your Sonic Hologram Generator, which I've been using for 30 years, will work with your Amazings, or even your HTS series? I have a dedicated room made especially for holography, and I prefer it over multi-channel systems! Thank you, thank you, thank you for everything! Tony. Jun-18-10
A: Hi Tony, Wow! You have a room made for holography? That is so special. Really. As for tube amps, I actually grew up with them - they were my first amp designs, with my solid state designs coming along sometime later with my first amp, the Phase linear 700. Tube amps have always been a true love, and I consummated that love with my Silver Seven vacuum tube amplifier during my Carver days. And yes, Sonic Holography will work beautifully with the Amazings or HTS series. It's important that early reflections be minimized in the setup however. All this is outlined in the manual, and is no different from the setup required for the best conventional stereo presentation. Minimizing early room reflections allows our ear-brain system to do its job and build a sense of three-dimensionality in our minds. We can then use the time cues inherent in the recording, and our brain does the rest, building that large, believable three dimensional space in our minds. Very realistic and enjoyable. Bob Carver
Q: Hi Bob - beautiful amps...but why did you use that cheesy Radio Shack volume knob? Some sort of yin and yang thing? Ha ha. On a different subject, I have your old M400 cube amp, and it's failed on me once again. Who do you recommend for repairs? -MarkS. Jun-18-10
A: Hi Mark, I used it because I think it's a beautiful knob. It's shiny polished aluminum, is machined as true as they come, has a perfect-fit center hole without run-out, a steel threaded set-screw, and finally, very nice knurls that ring its outer circumference allowing easy rotation. CHEESY?!?! No way! It's the perfect knob! Who do I recommend for repairs? Me. Send it to Bob, c/o Rita's Vintage Audio Repair. Rita and I will fix it right up - we'll even update it using extra big SOA (safe operating area) output transistors; hopefully it will never fail again. Thanks,Bob Carver
Q: Hello Bob, Ive always enjoyed youre amps as theyve always been a great value.The M 400 cube was very powerful.I wanted to ask if you remember the Spectro Acoustics 200SR amp and what you thought of the design.I always wondered why no other manufacturers put large meters on theyr amps as well.Thanks for youre time Jun-18-10
A: Hi 'ales, I do indeed remember the Spectro Acoustics amp - It was designed and built by two talented and passionate guys who worked for me at Phase Linear long ago. They struck out on their own and founded Spectro Acoustics after learning their craft right here in Lynnwood WA. As for meters, I seem to remember that Phase Linear, Marantz, McIntosh and S.A.E. were about the only ones using large meters - okay - maybe they weren't THAT large! Thanks for the fun trip down memory lane, Bob Carver
Q: Bob, First of all, thanks for your wonderful contributions to the world of audio! I have enjoyed music provided via a TFM-30/CT-3 combo for many years. Quick question: Why are there few tubed amplifiers which incorporate a switch-mode power supply? Seems with the correct filtering and whatnot the DC would be DC akin to that of the analog flavor. Anyhow, Best regards, A6EMech. Jun-18-10
A: Hi 'mech, I don't know. There certainly is no scientific or sound quality reason that I can think of. Perhaps it's just that mixing vintage tube circuits with contemporary digital switching circuits is too unsatisfying from an emotional or pure intellectual perspective. I'm pretty sure that's the reason! Bob Carver
Q: Very nice amplifiers! In your listing you discuss input and drive circuits and topologies. I have designed and built an amplifier that uses a JFET differential input stage direct coupled to a 6SU7 long tailed pair (surrent source biased) that has a 6SN7GTB follower. It will swing +/- 250 volts with a THD less than 1% and an IMD of less than 0.1%. It sounds great too. Actually anyone that has auditioned it is amazed. If you have any interest in seeing my circuit, please contact me at tomdooling@charter.net. I'm not selling anything, I'd welcome the opinion of the master. Thanks! Jun-18-10
A: Hi 'mby, I would love to see your circuit - the more circuits I can study in my life, the smarter I'll become, and it sounds as if your circuit is something to be extremely proud of. There is no doubt that a long tailed pair, current source biased, is definitely one of the best there is. Keep on building and designing! Precious few endeavors are as fun and as rewarding. That's for certain. Thanks for sharing, Bob Carver
Q: Thanks for the advice to Horizontally bi-amp the Infinity IRS Betas when I get my 2nd Sunfire Signature. Before asking you I only came across one or two of readings that specifically addressed Planar speakers and their thoughts were that Hor. bi-amping was a better way of running them vs. Ver. The Sunfire Sig. I’m running now with the Betas is the 5 ch. model and I have the Mids & Tweets on the Current output and the Bass on the Voltage output. They mate perfectly. That Current option is just the best. You are Bleeping Brilliant. I read that Arnold Nudell designed the Betas Mid/Tweeter column exclusively with tube gear, I’m sure you probably already know that, but I believe that is a major reason your Current outputs mesh so well with the Betas. Now to my question – IF I were to bid, it would be on a future pair of your amps because I’m not financially ready at this point, could I buy 2 sets, meaning 4 amps.? I would be willing to pay the identical winning bid price for the 2nd set Jun-18-10
A: Hi again '310, Great! You are right about Arnie, he did design them with tube amps in mind - I had many discussions with him about loudspeaker interfaces with vacuum tube amps - and I learned an enormous amount from him. Arnie is one of the great speaker designers of our time. As for your last question - yes, and yes. Happy bidding and lots of good luck, Bob Carver.
Q: I was 18 in 1985 when I went to work for for the local HI FI shop. I had been going there with My uncle since I was 10. I loved all the equipment, the lights, meters, The smell and of course the sound. I remember after working there for a short while I was told we were taking on a new line of high end gear, it was Carver. I remember coming in a few days later to see several customers, salesmen and My boss standing around a display of Dalquist DQ 9s that were just the day before powered by a huge Yamaha amp and pre amp. As I approached I saw this little gray box with two little LEDs. My boss said check this out. as he cued up the music I remember thinking "aint no way this little thing will drive these DQs like that Yamaha" Wrong!!! I could not belive my ears. over the next few days I listened and was amazed. from that point on I was hooked. I ran two M400t original advents from 19-28.as Money allowed from 29to43 I have 2 1.0T/Polk 1.2tl Bi amped. Just wanted to say Thanks. good job. Jun-18-10
A: Hi' togo, Hearing about your adventures of long ago makes me smile! It's fun for me know that my amp generated such surprise and astonishment - actually I could hardly believe it myself! Thanks, and thanks for writing, Bob Carver
Q: Dear Mr. Carver, I found the last question and your answer about bi-amping with a combination of tube [high end] and solid state [low end] amplification to be very illuminating. As a solid state devotee for the past two decades--mainly Carver you will be pleased to learn but Bryston too!-- I feel re-assured by your statement that tube amplification does not necessarily deliver a superior audio experience. Am I going too far with this statement? I always warmed to the idea, in a tube-like way, that Carver "TFM" was a real technology, that solid state amps could deliver the warmth of tubes and then some. Don't get me wrong, I would dearly love to collect a pair of Reference Silver Seven Tube amps (as you will likely be aware, a pair recently sold on eBay for a shade under $19k). It is refreshing to hear, however, that solid state amps should not be discounted. I agree that tube amps are super cool -- I mean warm! Best, Marc + Maria + beagles Vancouver, BC Jun-18-10
A: Hi 'oose, Absolutely! A great tube amp will sound wonderful, and a great solid state amp can sound wonderful as well. But they WILL sound different. A tube amp generally will yield a more enveloping soundstage and a greater front-to-back depth of field with tight imaging within that soundstage - a very romantic presentation. A well designed solid state amplifier will usually deliver a nice tight focus together with a greater up-front presentation. With these tube amps, a range of possibilities are possible, as the feedback switch and the bias adjustments allow the sound to be changed at will from very tube-like to almost solid state. This emerges naturally as a by-product of the DC restorer and the fact that the bias is "in the green" over a wide range of idling currents. Solid state amps are indeed not to be discounted - and thanks for your thoughtful and on the mark comments - they mean a lot to me. Warmest and best, Bob Carver.
Q: Bob. You sure got that "mad scientist" look on your face while winding that transformer! Thanks for sharing the pictures and your passion for audio excellence with us! John Jun-16-10
A: Hi John, You think? Now that I look at it again, I see the only things missing are bugs in my teeth from the winding machine. The camera "stopped" the spokes - they are actually a blur. Bob Carver
Q: Hi Bob, hugh fan! In a bi-amping configuration, would you use these mono blocks the the upper or lower end? What are the pros and cons for this approach? Jun-15-10
A: Hi '111, I would use these mono blocks for the high end and a solid state amp for the low end, unless you had two sets of these amplifiers. A vacuum tube amp by its intrinsic nature will yeild better bass because its output characteristic allows the signal to follow the impedance curve of the speaker system, delivering more voltage to the system within about an octive of its resonance frequency. This usually delivers a more satisfying low-end response. However, what normally happens in the real world is that vacuum tube amplifiers lack the raw power to effectively accomplish this; typically a solid state amp is more able to deliver the power needed and therefore works better. But NOT if we have four of these very powerful tube amps. Good question, Bob Carver
Q: Are the 180 watts rms pentode or triode? Jun-14-10
A: Hi '4t, This is one of those simple questions with a very complex and extended answer.The answer here is pentode, but that's only the beginning of the story. Long, long ago, in the '30s and '40s the only way to build an amplifier without notch distortion was to build it class A. Many talented amplifier designers worked and worked on the this problem until at last a genius by the name of Williamson arrived and taught the world how to build a class AB output stage that was completely devoid of of notch distortion. This was late '40s - a breakthrough and the hi-fidelity industry took off. However, to work right, triodes were required which limited power efficiency - still, the leap in efficiency from class A to class AB was huge, completely overshadowing the fact that troides were not as power efficient as pentodes. Triodes were still needed to make notch distortion go away as the the art of output transformers had not yet been developed to their fullest. This was was because triodes had a characteristic known as "low output impedance" and could easily overcome the problems of leakage inductance in the output transformer. It took the genius Gordon Gow,a founder of McIntosh to teach us how to build a high efficiency class AB output stage WITHOUT notch distortion. Others followed suit at Marantz, Citation, Scott, Fisher and on and on. Today it is not difficult to build a class AB amplifier without notch distortion, thanks to the amazing pioneering work of those early guys. So - we see we went from triode class A to triode Class AB, and finally to pentode Class AB as the years trolled by. Often old ideas die hard, and to this day a false belief sometimes exists that triodes are still preferred in class A. It IS easier to design with triodes, but a superbly designed pentode stage will easily out-perform even a well designed triode stage. Any difference in sound is associated with the circuit itself, not the choice of pentode or triode. Thanks for the question, Bob Carver
Q: Hi Bob. The Carver Carver KT88 are gorgeous mono-blocks. If only we all could have one : ). Do you plan to sell more items on ebay? Thank you for the imagination, honesty, and fun you put into audio. Best regards, John Jun-13-10
A: Hi 'head, Well, as I've said before, Bob's my name, and amps are my game. I could not stop building amps even if I wanted to.I hope YOU are having as much fun as I am in this arena after all these years. Thank you John for your kind words - they really do mean a lot to me. And yes, If only everyone did have one there would certainly be no more wars, sickness or sadness. Of that I am certain! Warmest and best, Bob Carver
Q: I seem to remember reading this story in 2008! What are your comments to this? http://newsgroups.derkei...es/2008-07/msg00075.html Jun-13-10
A: Hi 'infs, I could not open this. What does it say? Bob Carver
Q: Hello Bob.I am Karlheinz from Germany.Yes same all , i say you are fantastic electronic inventor.I have a part and no find discription: Carver PG/2 Dual Zone Music /Paging System.If you have the time for sends informations, i say mny thanks to you from Germany Black forrest.Karlheinz Jun-13-10
A: Hi Karlheinz from the black forest, I used to live in Germany and I remember the park at the end of my block with BIG swings and a teeter-totter. My young German friends and I used to pretend we were in the black forest. As for the Carver system, I have the time , and I would be glad to; I'll look for the information next week when I return home, but please e-mail me late next week and remind me so I won't forget. Warmest and best, Bob Carver
Q: Mr.Carver, Wow,super nice eye candy.Can you please tell me what caps you used?Thanks, Dave Jun-13-10
A: Hi '62, I like eye candy too! As for capacitors they are far less interesting than fine eye candy, but here goes. I use metalized film for the interstage coupling capacitors, each sized such that low frequency loop gain and phase shift is just right for perfect sub-sonic stability. The power supply caps are HUGE - way over-kill for energy storage. They can hold so much more energy than vintage designers could ever even dream about - thanks to new capacitor science. Great question, Bob Carver.
Q: For some reason, the proper Ohm symbol is being changed to a "?" when I send my message. Sorry! Marc Jun-13-10
A: I got it, no worries, Bob Carver.
Q: Oops -- "Ω"!! Dear Mr. Carver: In addition to being a big (Bob) Carver fan, I am a big vintage KEF fan. Am I being "unwise" using a TFM-75 to drive my (immaculate) 104/2's [4Ω/200W] or 107/2's [4Ω/400W]? Do note that I am very sensible with the volume, tone and input controls (I use a Carver C- 11 or C-19 Pre-amp). Final comment, I have "less powerful" amps that I can use (e.g. Silver Seven t's, M-4.0t's) but really love the mighty "75"! Thanks for your advice and time. Sure hope I am not unwittingly cooking or otherwise abusing my beloved vintage KEF speakers. Best, Marc + Maria + beagles Vancouver, BC Jun-13-10
A: Hi Marc and family, Oops, it's good to see you again. Bob Carver
Q: Dear Mr. Carver: In addition to being a big (Bob) Carver fan, I am a big vintage KEF fan. Am I being "unwise" using a TFM-75 to drive my (immaculate) 104/2's [4Ω/200W] or 107/2's [4Ω/400W]? Do note that I am very sensible with the volume, tone and input controls (I use a Carver C- 11 or C-19 Pre-amp). Final comment, I have "less powerful" amps that I can use (e.g. Silver Seven t's, M-4.0t's) but really love the mighty "75"! Thanks for your advice and time. Sure hope I am not unwittingly cooking or otherwise abusing my beloved vintage KEF speakers. Best, Marc + Maria + beagles Vancouver, BC Jun-13-10
A: Hi Marc, Maria, and puppies, You are absolutely not being unwise with the TFM-75 provided of course that you use reasonable caution which you clearly are doing. The KEF speakers will let you know in no uncertain audible terms if you abuse them. Especially if you break them. Enjoy the music, play it loud, play it soft, Bob Carver
Q: Hello Bob Carver, I have enjoyed following you auctions this past year. I was wondering if you had ever measured the total watts being consumed by each amp, out of the wall socket, at idle? I was just curious what one of those Kill O Watt meters might read. I only have a 20 amp circuit coming into my listening room, and several things in there that I fire up when I use it. I have read where you list each KT88 tube at 42 watts at idle, and the DC restorer lowers that to 9.5 watts, but I don't know enough to know if that translates into 42 x 6, or 9.5 x 6 for each amp, or some other number. Sorry for the silly question, but old, inquiring minds are wondering? Thanks if you get time to answer, and best of luck with your "beautiful," both operational, and cosmetic, amp auctions. Jun-13-10
A: Hi 'igy, Not a silly question at all. And your math is correct, it is indeed 9.5 x 6 plus the power for the tube heaters for a grand total of about 120 watts plus or minus. Thanks for wishing me luck; you won't need luck though as your 20 amp circuit can easily deliver over 2000 watts. Hope this helps, Bob Carver
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From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

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(pair of) SILVER-7 TUBE AMPs

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Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:52 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Here's the latest Q&A from Bob's sixth set of tube monoblocks with meters. This set sold 5/12/10 for $7500, a full 25% less than the previous identical pair. There's not much new information revealed this time but this pair Bob designated at 240 watts compared to all the others listed as 180 watts. Again, due to the nature of the way eBay builds it's web pages you should start at the bottom of the post and read upwards to follow chronological order.

Q: not a question but a comment on your amplifier. they are certainly built with quality parts but the photographs of you manufacturing your transformers indicate,to me, that you are just having fun doing this. unfortunally i am not in a financial position to bid. i hope you are doing this for a while longer. i certainly would like to bid on a pair of these when my ship comes in. May-03-10
A: Hey 'mon (70's expression), there is no doubt in my mind that you will someday soon be able to bid high and win. In the meantime, keep on thinking about amplifiers as there scant few dreams that are as much fun or sustaining. I do enjoy winding my own transformers, and painting the chassis in my upstairs paint-booth bathroom. I intend to keep on doing this for a long, long time. Bob's my name, and amps are my game; I could not stop if I wanted to. Bob Carver
Q: Hi Bob, Let me state for all would-be bidders that this auction is truly from the real Bob Carver. I have the pair from Carverfest so I should know. But now I have to ask how you manage another 60 watts RMS without adding another pair of KT88's. I read below about the 1 ohm spec of 370 watts and how it takes advantage of your DC restorer circuit, but is your new 240 watt spec at 8 ohms? It makes we want to upgrade! Best of luck on this auction to you, Bob. cheers weitrhino May-03-10
A: Hi 'rama, Yes, the 240 watt specification is an eight ohm spec. And at eight ohms, the amplifier output tubes are loafing, operating at about 62% of maximum capacity (110 + 20) x 3 = 390 watts, and 240 is 62% of 390. An upgrade would give you more power, but not any change at all in the sound. Thanks for writing in with a cool question, one I should have addressed in the auction. Hope this helps, Bob Carver Hope this helps
Q: As there seems to be some question of Authenticity, will you please verify this auction by answering this question for me. - Aside from a pair of these beautiful amplifiers, what other item did you give away in a raffle 2 years ago at CarverFest in North Carolina? Thank you for your response. Ed May-02-10
A: Ha! Thought you had me, didn't you? It was a pair of my Sunfire Cinema Ribbon loudspeakers, the ones that got a mind-blowing review by Robert Harley in The Absolute Sound. Wow! I sound like a pitch-man, don't I? Oh well, I can't help it. Bob Carver.
Q: Hello Bob. Is it possible to have both you and Tubular Joe sign these amplifiers should I win? Hope to hear from you, Kevin May-02-10
A: Hi 'tvr-1, no problem. However you should know that Tubular Joe has poor penmanship. Just kidding! We will inscribe anything you desire, in gold, on the shiny black output transformers. Bob Carver
Q: Hello Mr. Carver. I live from Italy. Please tell me it is possible to ship to Italy, and cost. Andrea Croci May-02-10
A: Hi Andrea, yes I can ship to Italy, and the cost would be about U.S. $350 dollars. Good luck! Thanks for your interest. Bob Carver
Q: Would you mind telling me your dogs name? There have been quite a few bogus auctions on eBay lately, and I like to make sure you are really Bob Carver. Thanks. Bill May-02-10
A: Hi 'olt, It's Zeus. He is a small, black British water spaniel with more love than all the amps in the world. Even 240 watt red ones. He has a BIG name though. Thanks for writing, Bob Carver
Q: Greetings Bob, I am very curious to know how you get so much power from this amplifier at 1-Ohm? Thank you for your time, Thomas in Texas. May-02-10
A: Hi Thomas, Great question! Easy. Well, maybe not so easy; we have to realize that the mighty KT88 is rated for 110 watts rms audio per pair. Additionally, each tube is rated for 42 watts of plate dissipation(at idle), and most vintage amplifiers operate with the idle dissipation at about three fourths max, or 32 watts per tube. Now thanks to the DC restorer, this amp idles at only 9.75 watts per tube, and about 60% of the remainder becomes available as output power. So we have 110 + 0.6 x 22 watts = 123 watts per pair. Finally, three times 123 = 370 watts total. Thanks for asking a great question, Bob Carver
Q: Q) Who was the Australian importer when the AL111 was in prodution? Nun_ _ . from Pr_ _ _ . Just looking to verify authenticity. (Hope you knew) Regards, Steven. May-02-10
A: Hi '87, I can't remember, remember I was old when Atlantis sank, and it was twenty years ago. Besides, you're supposed to ask me something I know the answer to, like my dog's name. I remember that! Thanks for the fun moments, Bob Carver

Q: Hi Bob, I have a quick question. I have a Carver M 4.0t Silver Seven Vacuum Transfer Function Amplifier with a Carver C 16 preamp and hi-end Audioquest interconnecion cables. I'm also using your Loudspeaker Control System I usually play classical and jazz music. What kind of speakers do you recomend for my Carver system? What are my options. I have a pair of Bose 502 and it sounds rather dull. Thanks For Your Time Jorge Hernandez Pismo Beach, Ca. May-11-10
A: Hi '123,Check out my Cinema Ribbon loudspeakers. They were reviewed by Robert Harley in the Absolute Sound and received an incredible review that manufactures normally would die for. Even me. I designed them to have a big soundstage with pin-point imaging within that big enveloping acoustic. Google Absolute Sound and search, or go to the Sunfire web site. I promise as my name is Bob Carver, these speakers are just the ticket for your classical and jazz. Thanks for writing and for the question, Bob Carver.
Q: -Hello Bob, I have been a fan and happy listener of your incredible insanity from the moment I purchased a new M400 cube amp years ago. Today I have a pair of A760x amps, a C-19 preamp, and a SD/A 490t CD powering a pair of KEF 207/2 reference speakers. My question is this - being unable to muster the mojo to purchase the recently offered pair of Silver-7 tube amps, I am wondering what the audible difference would be if I purchased these tube amps for auction and used them in place of the a760x's.... less power for sure, but honestly I have never owned a tube amp so it is a mystery to me ... any thoughts you could share? Thanks for your time and many years of happy musical experiences. -Gary May-11-10
A: Hi '6b, Ummm ....your eBay handle sounds like a tube amp. If you have never owned one (a tube amp) before, you are in for a real treat. Once we have experienced a tube amp , we can never go back. As for the power, tube amplifiers sound as if they are about half again as powerful as their power rating would infer. There are a variety of technical reasons for this, but just beyond beyond the scope of my short answer here. Still, it sounds as though you are getting some great sound. Thanks for writing, hope this helps. Bob Carver
Q: Hi Bob, Unfortunately, I am over loaded with amps at the moment (9 or 10 I think)or I would give these a whirl. I would like to ask you: who you would recommend to service my vintage tube ARC D-79 amp in the Seattle area? I live on Bainbridge Island. I thank you in advance for your reply. Kind regards, Bill Roberts May-10-10
A: Hi Bill, No sweat, bring it into Rita's Vintage Audio Shop in the old Sunfire factory right here in Snohomish. Bill Flannery is the vacuum tube technician and we work side-by-side on the vintage tube amps and pre-amps on weekends. Bainbribridge is about 35 minutes plus a fun ferry boat ride from Snohomish. Thanks for writing, Bob Carver
Q: Hi Bob, It is so cool to see you building tube amplifiers! My name is James. I used to work for Carver from 1989 until 1998. I worked for Sunfire from 1998 until 2007. If you ever decide to go into production again building amplifiers or audio equipment, I would love to work for you. I am very good at all kinds of mechanical assembly and soldering work. In fact, in the final days at Sunfire I built the last of the true American built Sunfire amplifiers from start to finish. I am a very hard working and efficient assembler, with great attention to detail and a true commitment to quality. Those tube amps with all that point to point work look like they would be very fun to build! Please give me a call if you are interested in my help. Best Regards, James Keener (425) 346-4856 May-10-10
A: Hi James, I just answered this. Hi again! Boo! A friendly ghost. Bob Carver
Q: Hi Bob, It is so cool to see you building tube amplifiers! My name is James. I used to work for Carver from 1989 until 1998. I worked for Sunfire from 1998 until 2007. If you ever decide to go into production again building amplifiers or audio equipment, I would love to work for you. I am very good at all kinds of mechanical assembly and soldering work. In fact, in the final days at Sunfire I built the last of the true American built Sunfire amplifiers from start to finish. I am a very hard working and efficient assembler, with great attention to detail and a true commitment to quality. Those tube amps with all that point to point work look like they would be very fun to build! Please give me a call if you are interested in my help. Best Regards, James Keener (425) 346-4856 May-10-10
A: Hi James, Sure is fun to hear from you - a nice blast from the past. I have a day job at Sunfire, so I work on these amps in the evening and on weekends, and Tubular Joe builds them when he has time. About eight amps per year. A complete labor of love for us both. Still, perhaps we could build some more if you pitched in - I remember your build quality was extraordinary! Even remarkable and amazing - you were a perfectionist's perfectionist. Let's talk ; call me after the auction is over if you come up for air and if you can. I'm looking forward to talking. All my best, Bob Carver
Q: HI BOB ¡¡ I HOOCK THEM UP ¡¡ They sound GREAT... ever so sweet " Maravilloso" , Im so Happy , great packing to¡¡ they arrived in perfect shape.. sending pics check your mail THANKS FOR ALL May-09-10
A: Hi '816, You won my earlier auction! They arrived safe and sound - a long journey, and they work. GREAT, ever so SWEET. I'm happy when you are happy. Happy Birthday, even if the earthquake delayed their arrival. All's well that end well. Thanks for letting us know, Bob Carver
Q: Bob---I just found a fraudulent amp auction and put a huge bid on it. Thought you'd want to know. May-09-10
A: Yes I saw it too. And I outbid you. I put a bid of $100,100 dollars. I cannot believe that eBay cannot take this down, but so far they have not done so. They are trying, but said it takes up to 24 hours. It is a one day auction, so that will not help. The real damage is that persons who send them $2000 dollars will certainly lose it all. The good news is you can tell it's fraudulent by my huge outrageous bid! Thanks for letting us know; It help us all. Bob Carver
Q: Hi Bob, Your favorite fraudster is at it again. lol he doesn't give up. 320529753027 May-09-10
A: Hey Man, you gotta be kidding! Guess not. Okay, I'll contact eBay, inform them of the fraud, and ask them take it down. Thanks, Bob Carver.
Q: Hi Bob , Steve here in Washington...I have a question about you sunfire pre amp . the Theater Grand Processor II .....I also have a Sunfire 300~2 amp....On the back of the amp , it has Lab and regular inputs...In the manual , you said to use the Lab if there is no DC output from the Pre....Would it be safe to hook up the Sunfire Pre to the Lab input of the Sunfire amp...And thanks for your time Bob... Steve May-09-10
A: Hi 'op, Yes it it is safe. The Sunfire has a giant, and I mean a truly huge film output coupling capacitor just to make sure! Hope this helps, Bob Carver
Q: one last thing i just bought 2 pair of your CRS-3 speakers and want to use one or both pm-900's to design some variable subwoffers to compliment them, so if oyu have any spare ideas or thoughts i could use a few good part names to use in the build. randyhart420 May-09-10
A: Hi again, Any high quality modern part set will work beautifully. There are many to choose from; you can't go wrong with any of them. Honest. Good luck! Bob Carver
Q: hi Bob: it is me your problem child again. during the last auction you said you would ( after getting back from being out of town) you would hook my old disabled rear end up with the schematics, parts list and the places to get those impossible to find parts for the amps. i also wanted any recomendations for upgreding the a760X and pm900 as i have two of each. and now i am on disability retirement because of exposure to some bad chemicals at work i would like to tear down the amps and upgrade the resistors and capacitors(your recommendations) of course (not every single little res. or cap but the most affecting ones then try to build on of these because at 10 grand a pair it will be the only way i can own them. i would be graetly appreciativeam going with this one again my email is randyhart429@hotmail.com phone 909-213-4920 i know i am reaching but you are my hero and have been since a m1.0 drove a set of klipsch korners to the brink in 1999. randyhart420 that is ephesians 4:20 May-09-10
A: Hi '420, I'm glad you wrote in; I have a character flaw - I procrastinate too much. However, I'm working on the updated schematic and a parts list for you. I'll have it done next weekend. Do you have schematics for your Carver amps? Stand by my new friend, Bob Carver
Q: HI BOB Finally got my hands in your amps¡¡¡ Boy are they beautifull ¡¡ Im shure they will sound " maravilloso" Great. Thanks a lot I going to plug them sunday nigth One simple question are they 220 volts as we requested ?? Best regards from an "honor full " fan May-07-10
A: Hi '816, They made it! All the way to Chile. One ship, four planes, three trucks, one taxi! Not to mention an earthquake. Yea! Bob Carver PS: They are 220 volts.
Q: Bob, Sorry to use this format but this is what is available. 37 years ago I met you at a stereo store at Northgate when you told me how to add caps to minimize distortion on an Ortofon cartridge. I asked the owners who you were and when I found out, asked if you had any jobs. You sent me to see the VP (Steve?) at Phase Linear and I was hired to be a tech, specifically QC on the amp line. It was the best company that I have worked for. You know how to treat people/employees and taught me a great deal. I have followed your career and tried to see you a couple of times in other time zones but was out of town or unavailable. So thank you for taking a chance on a fairly disoriented Nam Vet and for giving me a life opportunity. I wish I had the coin for these puppies you are selling. I wish you all the best. Joseph Westphal May-07-10
A: Hi joseph, I remember that day - it was North west Audio and they carried Ortofon. It was long ago - we were young kids back then and here we are today still in the arena with the music playing on. If you ever make it to my time zone, look me up at Sunfire and let's have breakfast. I wish YOU the best, thanks for taking the time to write and for remembering, it has meant a lot to me. Warmest and best regards, Bob Carver
Q: Bob, I purchased the set of amps at the end of January and promptly became consumed with business travel and work, trying to keep my business interests alive in this awful economy, so sorry for lack of communications since. However, I wanted to tell you that I've finally had the chance to audition the Chery amps with Infinity RS1's, Gama's, Beta's, Sigma's and Epsilons; Sourced by both vinyl and CD's. As you may recall, my comparison amps include McIntosh 1201's, Onkyo M-508's, Silver 7-t's, TFM-45's & 55's and some other fine amps that I enjoy including some tube units. So the bottom line is simply that the Cheery's, as I like to call them, are truly astonishing. I was wrong to have doubted their ability to drive such power hungry speakers and the result is incredible. We've experimented with the feedback and like 'Classic' best. So thanks much for bringing these to life and keep up the good work! Hope many others can enjoy the beauty of your fine work. May-07-10
A: Yea! Me too! Bob Carver
Q: Bob. I don't get along to well with computers and email I can never figure out if a message goes throgh using this ebay route. Did you get a message concerning dc restorer in two stages the secong beginning with OOPS? neal May-06-10
A: Hi 541', Nope. I did get it the second time you tried. Don't feel funny though - I too can barely turn my computer on - at least that's what my daughter thinks of my computer skills. I deny that of course, and tell her I'm a computer expert. Bob Carver
Q: Not a question Bob but I want to let you know I how have the second amp finished am am listening to two now instead of one, that I built from the schematics that you sent me, It' up and performing and I must say I think I might have gone to Heaven!!! I have been running the first one while I was building the second one and yes two are twice the sound as one. I have been playing a CD of The US Navy Band and The Sea Chanters and I am hearing sounds that was never there before. Bob I thank you for your encouragement. I don't have words to describe what I am hearing when I listen to my amps. Investing in a pair of your amps is a better investment than the Stock Market, stocks go down the value of your amps go up. Thanks again Bob. Your Friend, "jay" May-06-10
A: Hi 'music, I love it that you don't have the words to describe what you are hearing when you listen to these amps. But you do - you said you went to Heaven!!! Just don't die first. Thanks for taking the time to write 'music (Man) - means a lot to me, Bob Carver
Q: Hi Neal again. Maybe my question on the restorer didn't go thru. I will try again. If I recall the idle per tube as about 12 ma, right? Now if the amp is ramped up to full out put with still no waveform distortion, and the signal induced current could be magically stripped away leaving just bias current, what would this current be per tube at this level, with the dc restorer operating? cordially neal May-06-10
A: Hi Neal, I can tell you have been thinking a lot about the DC restorer. Your question is deep and very sophisticated - here is the answer, but first a thought experiment. Imagine a standard class AB tube amp with each tube biased such that each tube is dissipating 43 watts at idle, idling along at 70 mA. Now we drive the amplifier to full output, say 75 watts and measure the DC value of the cathode current with an ammeter. We write it down. Back to idle. Now we turn the bias control all the way down (max negative bias voltage) to say five mA. We again drive the amplifier to maximum output, 75 watts. We once again measure the DC value of the cathode current. What do you think the cathode current will be? We find that it is almost identical to the current that existed when we operated the amplifier at maximum quiescent dissipation! In other words, the large drive level acts as if it strips away the high idle current. This is an astonishing result, is hard to believe, is non intuitive, AND it is the TRUE nature of a class AB output stage. The DC restorer mimics that nature, except of course on the low end of the output tube dissipation. It works because the crossover distortion (eliminated by idle current) occurs at the zero axis crossing, NOT at the peak of the output waveform or anywhere in between. During the crossover period, a well designed output stage is operating in pure class A and with AB symmetry, hence zero distortion. The DC restorer allows the output stage to operate instantaneously in class A during crossover, but not at large outputs where it would only make things get hot at idle. Remember, at small output levels, class A does not require much current at all. So, as you can see, the answer to your question is 12 mA. This is such a difficult concept to understand and get our arms and mind around, I can see why nobody ever did it before. I got lucky, but only after banging my head against several sliding bias schemes, which are easily understood. Bob
Q: Hi...I have been looking up information on "pie winding". Now that i have wrapped my brain around the principle, tell me, how many primary and secondary sections are in those transformer? Neal May-06-10
A: Hi Neal, I'm not saying, it's my secret. However, "The Radiotron Designer's Handbook" published by RCA has an extensive chapter on winding geometry. pages 1205 and 1206, as well as the chapter beginning on page 210. Inspect fig 5.13E on page 213; you will see a pie winding chart showing thirteen sections for a very expensive output transformer. The chart also shows inexpensive transformers with fewer sections, all the way down to only two. There is a great DVD available on eBay called "Audio Transformer, Design and Construction". It contains 24 (!) complete books written by all the great transformer designers from the very beginning through the almost present time. I don't remember the item number but you can find it. Hope this helps. You are going to have lots of fun on your transformer adventure - I just know it - I sure did! Hope this helps, Bob Carver
Q: Hi Bob My question is not about this auction,although I would Love to own these amps,bob I have a collection of your amps,and the last one I purchsed was a lightstar reference,I always thought it was the last amp you designed before leaving carver corp.can you tell me how of your design is in this amplifier? thanks David May-05-10
A: Hi David, It was indeed the last amp I designed before I left. I had designed and finished the first prototype, and it was my colleague Vic Richardson who completed that work by putting in the finishing touches and preparing it for factory production. A major undertaking. Vic and I have worked side by side forever since Carver was started, and he currently works in the engineering department with me at Sunfire. The Lightstar circuit with its tracking power supply became the tracking down converter and my first Sunfire amplifier. Bob Carver
Q: Hey Bob I'm a big fan currently use Slver9T with a carver sonic H C-3 , and a great pair of your ALS111 ribbon speakers. Had it all for about 14 years works flawless,Crystal clear sound and affordable,Thank you May-04-10
A: Hi '3765, I love it! Man, you are making my day, I enjoy hearing that my designs have been a powerful force for good in peoples lives, and that the music plays on after all these years. Fourteen! Thanks for taking the time to write, it means a lot to me. Bob Carver
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
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TNRabbit

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(pair of) SILVER-7 TUBE AMPs

Posts: 13301

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Mon May 16, 2011 5:54 am

Re: Tuberific Q&A from one of Bob's eBay auctions

Here's the Q & A from the tube amp auction that closed 4/11/10. These amps would appear to be identical to the previous pair sporting a built-in meter and featuring Bob's self-wound transformers. Incredibly these amps sold for $10,099! The auction price jumped from $7100 in the final 5 seconds!

Q: Greetings Mr. Carver, I just wanted to verify the shipping amount. The automatic pricing through eBay is telling me shipping the shipping cost is only $13.00. Can you please tell me if this amount is correct. I would expect the shipping for these beauties to be much higher. Thank you, Tom Apr-09-10
A: Hi Tom, Oops! I goofed and did not catch it. That's a recent shipping amount for my vacuum tubes I sold about a week ago. The return is wrong too - (See below). Good catch! Thanks, Bob Carver
Q: Hi Bob, Our fraudster is at it again. Takes some kahunas to post your ad when you have one currently ongoing. Item 220586768202 Larry Apr-09-10
A: You gotta be kidding! Guess not. Thanks, Bob Carver
Q: Hi Bob, any thoughts on how this new tube amp compares with your earlier Silver 7/9 in terms of fidelity, sound quality, current etc..How would compare its current/sound capabilities with the Lightstar Reference? Apr-08-10
A: Hi '914, Boy that's a hard question - it's sort of like asking how would you compare your first born with his or her siblings. My answer is - I think they are all wonderful and I love them all the same. Though I will say that this amplifier represents my latest thinking year 2010. Good question, hard question. I wish I had a "better" answer, but I don't! Bob Carver
Q: Bob, will you be putting up another quad of the KT88 Eagles, or possibly, I might be able to buy a set directly from you. Put a question in on the last set but apparently too late. Thanks, Timothy. Apr-06-10
A: Hi Timothy, I'll put up another set in about a week - I'd do it sooner but I have to go out of town for a week, so I'll do it as soon as I get back. Of course I would like to sell direct to you, but it makes me feel funny, so the answer is no. I apologise from the bottom of my heart, and hope you bid and win next time - I've got my fingers crossed. Thanks for joining my auction, Best, Bob Carver
Q: hello there! first i have to say that i just love the color you have paint to this quality amps, and wonderful design.. and my question are, is it important to have the same ratet outputs level Vrms from preamp to amplifier?, 2Vrms,1Vrms,or more. and will it be less distortion if i use the same type brand? Kindly regards Tone Apr-06-10
A: Hi Tone, I like the color too: we tried several different hues and shades of red until we hit on this red. It has a nice sheen and carries just a touch of strawberry with a subtle bit of metallic embedded in that strawberry. As for the preamp, ANY high quality preamp will work great and give great sound - that's because preamps have been essentially standard since the very beginning. Good question, hope this helps, Bob Carver.
Q: Hi Bob, I bet you didn't waist much time posing and taking that picture of you holding that fantastic amp!! Most every one knows your qualiy amps. It will be interresting to see what the final bid brings! Al G. Apr-06-10
A: Hi Al, Thanks for your encouraging words - it means a lot to me. We will see when all's well that ends well! Warmest and best, Bob Carver
Q: Hello- I want to make sure it is really you and not a fake- what is my dogs name? Apr-06-10
A: Zeus, now for the $64,000 dollar question - is he big or is he small? Thanks for the humor. Bob Carver
Q: I just wish these were mass produced. Beautiful amps!!!!!!! Well worth the money and then some. Just can't do it working at a group home with juvenile delinquent low functioning sex offenders. Apr-05-10
A: Hi 'stone1, Even though you can't buy them now, the future definitely lies ahead, and who knows? Maybe someday - even in the very near future! In the meantime your work is absolutely a powerful force for good, and then some. Enjoy window shopping - I do it all the time. Thanks for writing, Bob Carver
Q: Would you sell a pair of your output transformers and a schematic??? Apr-05-10
A: Hello 'intell, I'm happy and flattered that you asked for my transformer and schematic. The schematic is free, but it takes me a full day to wind two output transformers; I don't have any extras, so the answer is no regarding them. However, there are some commercial units that will work great - let me think about which ones and where to buy them; let's get in touch after the auction is over and I get back from an out-of-town trip in a week and a half. Hope this helps, thanks for writing, Bob Carver.
Q: I would be most interested to see what you could create in a state of the art amp, either integrated or power, based on the lowly little 6BQ5 power tube and the 12ax7 signal tube. One that could actually be used with something besides only extremely efficient speakers would be exciting. Has this ever been brought up in any of your discussions. Impossible doesn't seem to be included in the scope of your creations. Come on let's upset the apple cart. Apr-03-10
A: Hi 'near7, Okay, here goes, I would use the 12AX7 as the voltage amp driving a Stu Hegeman style phase inverter. I would use auto-bias but with a difference - it would have a DC restorer circuit and a voltage clamp for that bias circuit. The 6BQ5's would run cool and the high distortion that ALWAYS accompanies cathode bias systems when driven hard would go away. This would give new meaning to the six barbeque five circuit (6BQ5) - now cool as a cucumber. I calculate about 28 watts rms per pair of tubes. Or 56 watts useing four 6BQ5's. Thanks '7, that was fun! Dream on, Bob Carver
Q: Hi Bob...Have a pair of your excellent early "Citation brown" mono 180 amps /w original trannys. Sound is gorgeous! So glad to see you've finally rolled a new 'big output iron' of your very own (just like the old Silver Seven days, right!) And looks like even a lack of vintage parts can't slow you down! BRAVO! The vintage tranny's deliver, I think, about 26 A output swing and the wave response capability was very, very high (forget exact V/us) before core saturation set in. How does your new tranny design comnpare w.r.t. the characteristics/specs you observed from the 'vintage-original' trannies you obtained from your college days (installed on the earlier release 'Citation-brown' 180 monos). Thanks, and BTW nice cosemetic improvements on the newer design! - straylight Apr-03-10
A: Hi 'light, Necessity is the mother of invention; when I ran out of the vintage trannys, I had to figure out how to "roll my own",as it were. I took the vintage ones apart, peered inside and copied them. The winding geometry was vintage, a geometry not used today because it is way too expensive. (And not necessary anyway.) New modern steel and a simple layer wound coil yields great sound. I was not able to find any vintage "iron"(steel actually), so I used the hardest modern steel known to man. I copied the pie winding and put the vintage winding geometry and modern steel together and got the surprise of my life. The output power went up as well as the bandwidth - a few Hertz better. The best part is the two units sound the same, exactly the same! I feel lucky, I got lucky. Thanks for a great question, and I am overjoyed to hear that your "180 brown" amps are still yielding gorgeous sound. Stay in touch, Bob Carver
Q: Good to see another auction and hope to win this time! I really wish you can manufacture these transformers and offer this as Buy It Now! What is the shipping to London and is this available in 230v? Thanks!! Apr-02-10
A: Hi ', oops! This is a double - I answered already! Anyway, warmest and best regards, Bob Carver
Q: Good to see another auction and hope to win this time! I really wish you can manufacture these transformers and offer this as Buy It Now! What is the shipping to London and is this available in 230v? Thanks!! Apr-02-10
A: Hi again '871, I'm happy to have another go also. Maybe someday I'll manufacture these transformers, but for now this is all I have time for. As for London, the cost will be about U.S. $ 265 each, and yes it's ready to go for either 230 or 240 as the transformer has a split primary winding; it's easy to hook up either way. Hope this helps, Bob Carver
Q: Bob, AWESOME to see another Pair of GEMS from you again! My bid is in... Palm Springs CF is on Hold at this time, Very sorry but working on it still for down the road. Let me know if your ever this way I could show you my friends Audio store & my set up and buy you a Diet Pepsi. Cheers Apr-01-10
A: Hi '500, Man you are making my day! Irony has it I was down your way last summer but did not have much time to spend. Maybe this coming summer - I like Diet Coke but a cold Cheers will do as well. Thanks for your bid, warmest and best, Bob Carver
TNRabbit
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From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
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