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

Q&A from the latest Carver tube amp auction which ended Saturday 1/30/10. Of particular note is these are the first amps sold to have Bob's self-wound transformers. It would appear these new transformers, wound to copy his original vintage military spec transformers, are actually capable of delivering more current but would require another pair of KT88 output tubes to take advantage of this.

Q: I think what you did in producing this amplifier surpasses anything that has ever been done before. Please think twice, or more, about not doing another. After all the advances with digital. I feel that there is a slow changing of the tide back to analog reproduction of music. There is no reason why we can't have both. Please, continue to produce a high end piece of audio equipment for those of us who appreciate it. Look at it in a different way. What if the Dead Sea Scrolls were written on digital media? Would we still be able to read it and with what program and hard ware? Hard copy is best and analog is the next best thing. Create a demand for it. Jan-29-10
A: Hi 'earl, ".....surpasses anything that has ever been done before." Earl, your comment has brought me to my knees and it leaves me breathless. I am completely at a loss for words. Thank you. Bob Carver
Q: Unbelievable you're personally replying to all these questions!!! Will you ever design a tube pre-amp? Especially one affordable to the common man? THANKS! Don Jan-29-10
A: Hi Don, I don't think that for me to design a tube preamp - at least in the near future - is in the cards. But you never know. It turns out that my earlier vintage Sunfire tube preamp is now available from time to time here on eBay. It's used but it might as well be new as far as performance goes, and even if it isn't, I can fix it. There is nothing like a good preamp for sheer joy! Keep on listening and enjoy the music. Bob Carver.
Q: Hello Bob, Well this ones almost over and I just wanted to wish you Good Luck and hope this one brakes a new sales record on the price!!! Its worth it I hope to see you at the new West Coast Carverfest near Palm Springs Please come if you can! Still working on details though. No need to post this one public & I will watch this to the end - Again (GOOD LUCK)... Jan-29-10
A: Hi '500gt, West Coast Carverfest! Of course I'll be there! Why am I always the last to find out about cool and important stuff? Never mind - don't answer that - it's a rhetorical question. When is it? Where is it in Palm Springs? I love Palm Springs - sounds like lots of fun. See you then and there. I'm posting this in case anyone else wants to come. Several hours to go, so I can post more information if you wish. Warmest and best, Bob Carver
Q: as a young soldier in the military 1986,i spent every hard earned dollar on carver equipment.matched input/output voltages with gains and rocked everyone in the theatre.only u.s. pieces and all of them mismatched and pushed to the limit of stock,mildly hot roddeed and all the way stuff we could get.an era of carver few who knew and yet wonder existed everyday. rock on! Jan-28-10
A: Hi 'errs2, 1986 was a good time to be in the military, and it sounds like you enjoyed it immensely. If you were stationed at Fort Ord, near Carmel, California you were awakened each morn with a beautiful recording of reveille played through a Carver amp and piped to all those overhead speakers on top of high towers. Bet you didn't know that! Since I don't have a second thought on that, I'm stuck with the first. Just the same, I'm glad you wrote, and if you rock on, I'll rock on too. Warmest and best, Bob Carver
Q: Hello Bob, I'll bet by now you are more than ready for this auction to end as surely that lovely amplifier is getting mighty heavy! It has been very enjoyable reading your gracious responses to such a long list of questions and for that reason I and many others will be sad for it coming to an end. I can not believe how approachable you seem to be and for that reason intend on keeping track of your contact information. I have recently sold the audio business I started 30 years ago and the cash flow benefits that went with it. Fortunately my tube and tube unit collection will keep me good company in my retirement. Your comments regarding your first glimpse of an mc275 are what I would have said to you given the opportunity. Sincere best wishes, Jody Varey, Ontario, Canada. Jan-28-10
A: Hi Jody, Yes, I've been standing in the same spot for nine days holding that amplifier, but since it has magic it just gets lighter and lighter until it's going to float away with me holding on for dear life. I know what you mean about the auction coming to an end - it's sort of like closing the last page of a book and saying goodbye to all the wonderful characters. No goodbyes from me tonight though - I know how to wind great output transformers! Thanks for your thoughts, and I hope your retirement is as fruitful as you can imagine it. Bob Carver
Q: For years I proudly showed off my Nikko Alpha 450 amp. After seeing this listing I am officially apologizing to anyone I mislead into believing that I knew what I was talking about. This unit is simply amazing! Now if I could just win the Lotto in the next 33 hours … Jan-28-10
A: Hi 'leon3, I wish you good and hearty luck - lots of it. With my fingers crossed tight! Bob Carver
Q: Hello, Thinking about bidding on the amps, but what preamp would you recommend with these units. Thanks, Brenda Jan-28-10
A: Hi Brenda, My favorite preamp of all time is the Harmon Kardon Citation 1 preamp designed by an audio hero of mine, Stu Hegeman. If you can get one on eBay you will absolutely love it. If it does not work, I can fix it. Good luck Brenda, happy bidding. Bob Carver
Q: Bob, You ssay that you have a switch for 2 feedback settings. How many db of feedback each and do you feel that feedback is truly sonically and, stability, wise necessary with these amps or is it simply to satisfy the measurements crowd. Having built and experimented extensively with tube amps I have heard the loss of space and hardening of sound that accompanies increasing feedback. It is not necessary to the sound performance of a well executed amplifier only to validate specication measurements. The comment from EE's that it's OK applied in moderation defies the reality that even that has a significant detrimental effect on music reproduction. Of course some of these guys think that 20db of feedback is "moderate" also while they try to band-aid the performance of their transformers and circuitry. Also, when you say "current source" does that mean that you are using a depletion mode mosfet at the end of a long tail? Thanks! Dan Devin PS. Tim is quite a character isn't he! Jan-28-10
A: Hi Dan, The loss of space and hardening of sound you are experiencing is NOT the result of feedback or its lack thereof, rather it is a direct result of the way the feedback changes the amplifier characteristics. These characteristics may be designed into the amp and optimized through any number of ways, not just with feedback. If we remove all feedback, the internal resistance of the amplifier will be about twelve ohms or greater - that's too high. If the internal impedance is too low, the amp will short circuit the back-emf voltage from the speaker-room interaction and the system will sound dry and more or less like a flat curtain of sound strung, clothes-line style, between the speakers. If it is too high, the sound will be bloomy, swimmy, extra lush but with very poor focus and imaging. Listening this way can be fun for awhile but soon will make us want to get the "watery" feeling out of our ears. There is no absolute optimum internal resistance - it depends on our speaker, our room, and what's in our heads. Feedback is ONE way to modify these very audible characteristics. As for the long-tail, it's a 12AX7 with a resistor to minus voltage. And you are right - specifications are only part of a great sounding amplifier. AND no band-aids allowed! Bob Carver
Q: Actually, this is not a question about this item; I apologize. I am a huge fan of yours and I have an all Carver 2 channel system at home which consists of the Sunfire Classic Preamp, Sunfire Amplifier (300w) and a pair of Carver Amazing Silver Edition Speakers. The only non Carver pieces are the sources (until you decide to make a turntable ). I cannot tell you how much I love this system, with the right recording it sends chills down my spine. There is only one problem; I am one of the unlucky few to have bought a used Classic Tube Preamp WITHOUT the phono stage. I have seen that you are selling these amplifiers here on ebay and I am wondering if there is a possibility that you might have one of those phono stage boards laying around that you would consider selling to me? If not I will just continue my search. Regardless, thank you for everything that you do for us music lovers! Anthony Jan-27-10
A: Hi Anthony, Thanks for letting me know how much you are enjoying my designs, some long ago and some not so long ago - at least when measured in geologic time. As for the phono stage, I have three of them somewhere, but I need to look for them. In the meantime, please e-mail me, bob.sunfire@gmail.com and tell me if you use a moving magnet or moving coil cartridge. I'm looking forward to hearing from you, Bob Carver
Q: HI Mr Carver..looks like the biding its going to be strong Do you have the info on value to ship to santiago chile ?? I need a figure to see how high will I go again thanks. Jan-26-10
A: Hi '816, Yes, I just got it - expensive. US $262.00 for each amp, or US $524.00 for the pair. For that money, if you win and still live in Santiago, I'll ship four extra output tubes just in case. Warmest and best, Bob Carver
Q: Hi Bob! I grew up sanding boxes in the back room of Speakerlab, and now am a student of Electronic Engineering in Tacoma. I love glass audio, and have always been a fan of your creations, but these amps of yours really are my favorite! The amps themselves are beautiful in design, but hand winding your own transformers puts you and them in a league of your own. To own a pair would be to own a work of great art. As a student, I can't currently afford these amps, but I want to know if you intend to continue to produce them. I would simply LOVE to own a pair, and would not hesitate to allocate a months wages...I saw the first pair go, and am watching the second pair go; Bob are you going to make more? How could I convince you that I'm worthy of a Schematic? Jan-25-10
A: Hi 'dwell, If you grew up sanding cabinets at Speakerlab, you are definitely worthy of a schematic. As for winding the output transformers, I have to say it was originally David Hafler, the owner of Dynaco who taught me how to wind. I called him one late night in frustration because I could not get my prototype output transformer for the Silver Seven to work the way I wanted. He walked and talked me through it over the phone and when I finally - more or less - understood the science and the art, I asked how do I repay you for your time and graciousness? He said,"Bob, buy me a beer at the next CES show." I'm passing his generosity along; the schematic is yours. Go to the end of the auction and you will find a link to it. Thanks for writing, Bob Carver
Q: Hi, Beautiful amps. Maybe I missed it but what are the dimensions? Also, I have a McIntosh MC275. Could you tell me what you think the differences in sound might be. Thanks, Boris Jan-25-10
A: Hi Boris, 12 1/4" X 14 1/2" X 7 1/2" plus about an inch for the back panel connections. The McIntosh MC275 is an awesome amplifier, and is what started me in audio when one day long ago I rounded a corner and there in a store window was the most beautiful thing I had ever seen. Chrome, shiny black with form following function - a Mac 275. I was smitten! As for the sound - I designed this amp to deliver a large and lush soundstage with lots of power and headroom. Thanks for writing, Bob Carver
Q: Hello Bob, Would you mind giving a brief explanation as to why solid state amplifiers tend to double their watts, as the impedance drops by half, as where tube amps are not rated in the same way? i.e.. A solid state amp that can put out 100watts at 8ohms, is usually rated 200watts 4ohms, and 400watts @ 2ohms. Why don't these tube amps to follow the same rule? This was taken from your last auction ((Power is an easy 180 watts rms with a power bandwidth from 23 Hz to 45 kHz, frequency response 2 Hz to 85 kHz, and distortion less than 0.15 % at 220 watts out. --- One Ohm Drive Capability: This amplifier has been designed with big Apogees in mind, the one ohm kind. It delivers 305 watts into my Apogee Scintilla – I included a one ohm tap on the output transformer.)) So why arn't we looking at 1440watts @ 1ohm? Thank you for any help you can offer in explaining this. Bill King / PA. Jan-25-10
A: Hi Bill, Good question - here's my answer and I hope I don't put you and everyone to sleep. First, only the largest solid state amplifiers double their output power with every halving of load impedance. Most do increase, but not all that much. Solid state amps are very voltage limited, but normally possess an abundance of current. Tube amps are just the opposite - they have voltage that reaches for the sky, but are normally quite current limited. To get around that problem, tube amps have output taps for several load impedances, allowing full power to be delivered into any number of impedances. My solution is to use so many output tubes that lots of current and voltage can be be delivered at the same time. Each pair of KT88's is rated for 110 watts. So no matter how we slice or dice the power delivery, it cannot safely be more than 330 watts. No matter what the load impedance is. Having said all that, I arranged this design to allow the current to increase quite a bit with progressively increasing loads; the power increases even without changing taps, thanks to the mighty KT88's. However, at one ohm, the limit is reached and that's where the one ohm tap comes in. Wow! Whadda a question. Hope this helps, Bob Carver
Q: Hi Mr Carver, from Santiago Chile I am the proud owner of tfm 35, mt 1/5 , hr 895 5.1) Months ago I listened my first tube amp ( audio research ) and decided I wanted one....I remember seen you on E-bay selling an amp...It caugth my atention because Im a fan of your work but was not ready to buy, yet.... Days ago, Martin Riesco a friend and Tim de Paravicini costumer let me heard a custom amp that Tim did for him, great.. Loved and did a google search of tim de paravicini and some how I found your ebay listing, unbelived no?? Its Like they are mind to me, very interested on your amps but have some question... Chile as 220v grid...a problem?? a 220v to 110 volt transformer Will do it ?? will you ship air freigth to Santiago Chile airport?? I guess I could send them to Miami but will be much easier to me if you could ship them to Chile..can you get a quotation?. I consider an Honor just to get in contact with you, Sir. Excuse my English best regards from down Jan-24-10
A: Hi '816, What a small world it is. This amplifier has a split primary that may be easily wired for 240 or 120 volts. I designed it that way on purpose. And yes, I can ship to Chile or anywhere ships sail or Boeing or Airbus airplanes fly. After I post this I'll go to the Post Office site and get a quote. Look for it at the end of my answer to a following question. Warmest and best regards, Bob Carver
Q: Hi Bob, You have a better track record with your transformer than Ben did with his bulb filament. Like the looks of that winder and the transformer that you made with it is amazing. Keep 'em coming. Best Regards, Jay Jan-24-10
A: Hi 'music, Thanks, but I got rope (wire) burns until I put on the leather gloves. All was well after that, and I'm super happy that it turned out as well as it did. I have to admit I was worried for awhile. Thanks for your missive, Bob Carver
Q: You mentioned in an answer to a previous question that "this amp is a tube amp; with speech and music it will sound more than half again as powerful as its rms rating." How can that be? Aren't Watts -> Watts, Volts -> Volts, etc.? Thanks. joe Jan-24-10
A: Hi 'sram, Well, yes and no - it depends. A solid state amp cannot deliver more output voltage than its B+ and B- power supply. No matter what. But a vacuum tube amp can! A loudspeaker is a variable voltage source when it moves back and force; an engineer would say back-emf. A vacuum tube amplifier can easily track this back emf and deliver substantially more voltage to the loudspeaker voice coil whenever its back emf is relatively high. As an example, tonight Dave and I had a big eight ohm woofer on my laboratory bench and drove it with my eBay tube amp. The amp delivered 52.4 volts rms, whereas my solid state amp could only deliver 42 volts rms, yet the tube amp is rated for 180 watts and the solid state amp for 200 watts. Tube amp @52.4 volts = 343 watts, solid state amp @ 42 volts = 220 watts. That's why we often hear that tube amps are substantially more powerful than their rms rating - often one and a half times more powerful. In this example it was actually 1.9 times more! hope this helps. Great and interesting question, Bob Carver
Q: Since these amplifiers are (obviously) a stereo pair of monoblocks, they each have their own dedicated power supply (and power cord). How much current does it take to drive them at full output? Will it overtax my power line mains? Should I have two separate (dedicated) circuits to run these? Beautiful looking amps, by the way, especially the retro-looking meters on the front panel. Thanks. Dave Jan-24-10
A: Hi Dave, Wow! three at a time! Here goes: It won't overtax your power line mains one bit; the average input power is modest, and whenever a huge power transient comes along, the energy required is supplied from storage in the amp's power supply capacitor bank. They use less than four amps on average, a walk in the park for any normal wall outlet. No need to use separate circuits for all the above reasons. I'm glad you like the retro-meters - I found a nice stash of vintage meters on eBay and snagged them all. Thanks for writing, Bob Carver
Q: Now that you have duplicated (and improved, it seems) the output transformer used in these amplifiers, are you planning on continuing with them? Thanks. Jan-24-10
A: Hi 'amd, It's true I've "duplicated" the output transformers, but in reality I have not really improved them; they sound the same, exactly the same, as the vintage units I used in the earlier amplifiers. I used vintage wire, though that was not really important since elementary copper has not changed in the last 50 years, but I WAS forced to use modern steel. The new super-steel DID result in more power capability from the transformer, but in order to put that extra power use it I would have to add an extra pair of output tubes to the amplifier. The new transformer is everything I dreamed about or could possibly want, but without the extra tubes, it cannot deliver more power. Still, it's great to know I now have a totally over-designed output transformer, one that cannot possibly ever be a limiting factor. And yes, I absolutely plan on continuing with them. Great question, Bob Carver
Q: Hi Mr. Carver! (Bob, if I may.) I mentioned in previous correspondence that I struggle with the technical language, concepts (etc.) that audio engineers must use to do what they do. Can you recommend a book that will help a layperson, such as myself, understand the technical side of audio design/engineering? Does such a book exist? I note that you have a real knack for parsing extremely complicated technical issues and making them accessible for non-technical audiophiles. A second, unrelated question. . . Can you remember how many Silver Seven Vacuum Tube Mono Power Amplifiers were built by Carver Corporation? Is it possible to buy a pre-owned Silver Seven? Do any new Silver Seven amps still exist? Is Carver still in business?? Any help you can provide would be greatly appreciated! I realize that even a pre-owned Silver Seven would be very expensive. Sincerely, Marc + Maria + beagles Vancouver, BC Email: fuzzymoose@telus.net Jan-23-10
A: Hi Marc+Maria+puppies, Here goes one at a time: Thank you. We built about a hundred Silver Seven amps. Yes vintage Silver Sevens do appear on the market from time-to-time, and I know of a pair right now. They ARE expensive. New ones don't exist, that I know of, but that doesn't matter really, as these amps are so well cared for that they might as well be brand new. As for a book about audio, that depends. What technical level? Approximately. Let me know and I'll get back to you soon. Warmest and best, Bob Carver
Q: A Marantz Model 9 amplifier (tube) was measured in a Boston Audio Society Amplifier Test Clinic. The results were spectacular. It outperformed most of the modern transistor amplifiers in the clinic. It was among the lowest in distortion and its frequency response into a simulated speaker load was flat. It ranked with the best in the clinic. Will your amplifier perform similarly? Jan-23-10
A: Hello amf' again, Yes, but just to make certain I'll call Marantz and get back to you next week. Just kidding - read on. Excellent questions. Warmest and best regards, Bob Carver
Q: Given the low power of the tube amplifier you are selling, what minimum speaker efficiency do you recommend? Jan-22-10
A: Hi 'ail, low power?! This amp is a tube amp; with speech and music it will sound more than half again as powerful as its rms rating. That means it's almost 300 watts! The minimum speaker efficiency I would recommend depends on your listening taste. For reproducing wind chimes at realistic levels, I would say 72 dB SPL/one watt. For a full symphony orchestra, 86 dB. Hope this helps, Bob Carver.
Q: I heard that good audio tubes were hard to find. What source do you suggest for replacement? Alvin Jan-22-10
A: Hi Alvin, "Good tubes for audio are hard to find" is a false believe these days. There are many, many manufactures of excellent and wonderful tubes in existence. In addition, we can obtain great vintage tubes right here on eBay with a bit of looking. Bob Carver
Q: Bob, Why do you prefer tube designs? Alvin Jan-22-10
A: Hi Alvin, A deep and challenging question. It’s when we listen to them, some magic happens. Let me use as an example the soundstage as delivered by a tube amp, which generates a substantially larger acoustic space than a typical transistor amp. It does so by including the room in the musical presentation - the listening room becomes a significant part of the enveloping acoustic. First, we need to understand that our human hearing mechanism "likes" to hear ambiance; we like arrivals that are different in arrival times that can tell us something about the musical "space", where the music was made. Now, all amplifiers have two inputs, one for the musical signal, and one for the feedback signal. These two inputs are called "potentiometric" and "non-potentiometric”. As the amplifier makes the speaker speak, the sound leaves the speaker, travels to our ears, AND bounces off the walls of our listening room. In a tube amp, the bouncing sound arrives back at the speaker after a short round-trip delay and causes the speaker cone to move in response. It acts like a microphone, converting this energy into an electrical signal. The speaker is connected to the amplifier, and since the feedback loop is also connected to the amplifier, that "room signal" is fed back to the non-potentiometric input, is amplified once again, and appears as a voltage that drives the speaker once again as well. In other words, the amplifier has "listened" for and "heard" the room, and the room's character is added to the amplifier output. By doing so, the amplifier and room become an important part of the total acoustic. Solid state amps can't do that at all because their essentially zero output impedance shorts out the microphone/room signal, preventing the room character from playing its part. There are other reasons, but they are beyond the scope of my missive here. By the way, ALL amplifiers have feedback or its equivalent, no matter what the advertising says! Bob Carver
Q: Hi Bob, I'm in Calgary, Alberta. I have two active home theatre Audio systems in my home that you designed (Sunfire amp/pre-amp and receiver). Very happy with both, now looking to upgrade my 2 channel system. I'm wondering if pickup is possible? I have a good friend in Mukilteo, close to you, and he might be willing to pickup and store until I can drive down to Washington. Thanks, Greg Jan-22-10
A: Hi Greg, a pickup is indeed possible, and I would be delighted to load these amplifiers into your car. Or better yet, I'll deliver them to you, take you out to dinner, talk late into the night about audio, then troll around my old school, the UBC and relive wonderful old memories. Bob Carver
Q: Hello Mr. Carver. I was currious to know what is the most difficult part of designing such a high powered tube amplifier? Thanks for your time. Chris Thomas - NY Jan-22-10
A: Hi Chris, Oh Man! In 2000 characters or less, right? As Edison said, it's 1% inspiration and 99% perspiration. Designing the the first rough cut was pretty easy - all we did was draw the proposed circuit on a napkin, then we built it, and when it did not work, the real work started. There are several thousand refinements between that moment and the present amplifier, but the most (there are three) difficult design parameters to get right were the low and high frequancy compensation components. The last, and the part I spent by far the most time and effort on was getting the soundstage, the acoustic envelopement, and the imaging within that enveloping soundstage the way I wanted it. It was a man named Harry Pearson who first wrote about that long ago, and I remember being quite influenced by his teachings back then. Getting the soundstage right was the hardest. Hope I answered you question. Warmest and best, Bob Carver
Q: Hello Bob, It's great ro see you still coming out with great new products. Do you have any plans for any other new (home brew) products any time soon? If so, what might they be? It's great to see a legends mind still hard at work. Kudos to you sir! Jan-22-10
A: Hi 'o, Thank you for the kudos - that helps make my day. As far as more home brew - I don't know about right now, however I have always wanted to build a mind altering vacuum tube moving coil / moving magnet phono stage. Maybe later this year if Tubular Joe has the time to build one. I actually finished one 98% during my Carver days, but we never took it to market. All I would need to do is find the design and put in the finishing touches. Great question, thanks for asking, Bob Carver
Q: Hi Bob! Preamble then question. Big fan in Canada (Vancouver). Consider this exchange to be a real honor. Like so many, have always admired the sheer ingenuity of your ideas & products. Now 100% B&O (I know, "Boo! Hiss!"; wife!), but I sure get nostalgic for the "good old days" when (your) Carver brand was, for me, the equivalent of the indelible yellow hot rod in "American Graffiti." Always vowed that I would get a proper pair of tube amps. . . one day. Remember positively drooling over a pair of Silver Seven tube monoblocks that came through Edmonton as part of a Carver marketing blitz (I was a student at U. of Alberta working part-time at National Music; early 90's). Question: Do you plan to manufacture/craft any more of these unique amps? Not sure what they should command; I am guessing a lot. Perhaps I should just monitor this auction. Best, Marc "Moose" Baragar + beagles PS Your passion for great audio design still puts me under a spell. Jan-21-10
A: Hi Marc, Boy, do I remember that Vancouver trip well! It's as if it were yesterday, showing the Silver Seven to an audience of vacuum tube amplifier lovers, and with the University of British Columbia in the background. Speaking of which, I went to the U.B.C. when I started graduate school, and have great memories of Vancouver - a 90 minute drive from my own Snohomish, WA. As for building more amps, of course - Bob is my name and amps are my game. I couldn't stop buiding amplifiers even if I wanted to. Thanks Marc for a nice blast from the past. Warmest and best, Bob Carver
Q: Hi Bob, "Hockey Jersey Tom" from Pittsburgh PA here. Great set of amps. I am the current high bidder and will try to score them. I have a off topic question for you. What should the bias be set at for a M-1.0t amp. I have one side running a bit hot. What test points do I use? GREAT job on Brian Turners amps!!! Thanks, Tom Zurcher Jan-20-10
A: Hey Tom! High bidder! You are certainly passionate! Regarding the test points and the correct bias current, I don't know, but Rita does, plus I'll look it up tomorrow when I get to work. I need you to e-mail me with your e-mail adress so I won't forget, and I'm beyond glad to hear your M-1.0t is still working after all these years. I'm rooting for you. Warmest and best, Bob Carver
Q: Any chance you'd share a schematic of your new creation? Strictly for a hobby project. It's very encouraging and motivating to see what you're doing!! Thanks, Pete Jan-20-10
A: Hi Pete, I would love to share a schematic with you. Many have asked for a copy, so I'm going to post it on the Carver forum before this auction is over. If you want to go to the head of the line, send me a request at bob.sunfire@gmail.com along with your e-mail address and I'll send one. Hope this helps. Thanks for writing, Bob Carver
Q: No question here, Bob; just wanted to tell you I admire what you've done & continue to do in furtherance of audio nirvana! Congratulations on your latest power transformer epiphany~ --TNRabbit from the Carver Forum Jan-20-10
A: Thanks 'Rabbit, I'll tell you, I was a bit scared at first. Four unsuccessful tries before it finally worked had me thinking for a nano-second "What if I can't figure it out?". All's well that ends well. Bob Carver
Q: Is the bidding for both of these FINE tube amps? Thanks, Best, Michael Jan-20-10
A: Hi '1956, Absolutely yes. For both. I need to modify the auction to avoid confusion - I did not catch that when I listed it. Glad you asked and gave me the chance to clarify. Bob Carver

Q&A from the third pair of Bob's metered tube amps sold on 1/3/10 for $6600 on eBay. Of note, these amps used a different transformer than did the previous amps, in this case Partridge transformers that were a gift from Julian Hirsch, and as such had a slightly lower output but are still able to drive a 1 ohm load. I was amazed to see this sale jump from $4125 to the final price of $6600 in the last 90 seconds or so as I monitored the auction close.

Q: The CARVER CHALLENGE took place some time ago, before you designed the Sunfire amps, which I considered an improvement, but evidently, from what I understand here, even the best Sunfire amps don't have the sound of this tube amp, would that be a fair assessment? These two amps sure are sweet and juicy like these nutz. looking. And running the amps at low wattage dissipation, not pushing them, resulting in anywhere near a 50 year life span is an important advantage. Seems you have covered everything to make this superb ampliifer very desirable! Jan-03-10
A: Yes.
Q: Hi Bob, with a hour to go I am the highest bidder As for payment if I am the winner I do not think PayPal works at that high Dollar amount - What other payment would work for you? Fingers crossed I even get so far...THANKS!!! Dreams can come true! Jan-03-10
A: Hi '500, No problem, no worries. I have my fingers crossed too. Any rational way you want to pay works fine for me. Keep on dreaming! It's good for our dreams. Bob Carver
Q: That is a very interesting phenomenon regarding the speakers acting as microphones picking up ambiance! A real virtue for tube amps. I wonder if that signal could be accessed and fed to a solid state amp? Also, I recall that, in a demonstration years ago, that you were able to make a solid state amp sound so close to a tube amp that the listeners couldn't determine the difference. How did you manage to accomplish that feat? Jan-03-10
A: Hi 100', I did come close! Read all about it! Google THE CARVER CHALLENGE or go to the Stereophile website or the Carverfest forum - the article has been reprinted a lot over the years. Bob Carver
Q: Hello Bob, If you don't mind me asking, how do tube amplifiers make such a large sounding sound stage, that solid state amplifiers can't. Hope to hear back from you, Chris Jan-03-10
A: Hi 'bdn, They do it by including the room in the musical presentation - the listening room becomes a significant part of the enveloping acoustic. Here's how it work: First, we need to understand that our human hearing mechanism "likes" to hear ambiance, echo, multiple arrivals arising from even a single sonic event. We like arrivals that are multiple, different in arrival times, and can tell us something about the musical "space", the place where the music was made. Now, all amplifiers have two inputs, one for the musical signal, and one for the feedback signal. These two inputs are called "potentiometric" and "inverting". When an amplifier makes a speaker speak, the sound leaves the speaker, travels to our ears, AND bounces off the walls of our listening room. In a tube amp, the bouncing sound arrives back at the speaker after a short round-trip delay and causes the speaker cone to move in response. It acts like a microphone, converting this energy into an electrical signal. Since the speaker is connected to the amplifier output, and the feedback loop is connected to the amplifier output, that "room signal" is fed back to the non-potentiometric input of the amplifier, is amplified once again (both signals are always essentially equal to one another), and appears as a voltage that drives the speaker again. In other words, the amplifier has "listened" for and "heard" the room, and the room's character is added to the amplifier output. By doing so, the amplifier and room become an important part of the total acoustic. Solid state amps can't do that at all because they short out the microphone/room signal. They are intrinsically voltage mode devices, not current mode devices like tubes; their low output impedance literally short circuits the microphone signal, preventing the room character from playing its part. There are other reasons, but they are beyond the scope of my missive here. By the way, ALL amplifiers have feedback, no matter what the advertising says! Bob
Q: Hello! Ask this project, with what model Pre-amplifier optimum matching? Thanks! Jan-03-10
A: hi'inshi, a nice vacuum tube preamp would be a great choice but not absolutely necessary. This amp is easy to drive, so almost any modern or vintage unit will work nicely. My all time favorite vintage preamp is Stewart Hegeman's Citation I, with a close second the Audio Research SP-3a. My own Sunfire tube preamp is not yet old enough to be vintage, and my Carver tube preamp designed for the Silver Seven tube amp is impossible to find today. Too rare. Thanks for writing and for asking, Bob Carver
Q: Greetings Mr. Carver, How do you get so much power from a transformer that was designed to put out only 20 watts. Thanks for your time. Tim Jan-03-10
A: Hi Tim, I just knew someone would ask that. Here is how it works: In the old days(The Partridge was designed around 1947), output transformer design was almost pure art until D.T.N.(Also known as A.N.) Williamson designed the Williamson amplifier and the output transformer for it. The winding geometry was new and unheard of for the time, resulting in almost magical(It wasn't really magic of course)performance not to be believed. What he did was specify that EACH section of the output winding be brought out of the core, accessible on the outside. Each transformer has 10 secondary windings that may be connected in parallel, series parallel, or in any combination that we desire. This allows a wide range of impedance matching configurations; all I had to do was hook them up to match the impedance of six KT88's. Williamson made my job easy - the impedance is related to the square of the turns ratio - so it was a simple matter to match eight ohms to six output tubes. And Viola', 130 watts. This transformer is massive, huge, and when I first held it in my hands I thought "All this for 20 watts?". Now I know why. He must have known I was coming in the future. Since this transformer used an amplifier with an unusually high voltage supply, the volt-time product as designed for the primary is about 38 volt-seconds, or perfect for this amp and 16 Hz! That's how. Hope I didn't put you to sleep! Bob Carver
Q: Hi Bob. I have 1 question before placed bids: Those Golden Lion output tubes come with amps, are Reissued ? They don't look like NOS as mine, physically ! regards. Jan-02-10
A: Hi'du, These Gold Lions are Mike Mathews's (Genelex's owner) masterpiece! They are that good. As far as I can tell, he has been trying for the last decade to build a great KT88/6550, and I for one must say he has succeeded in spades with this tube. I begin: Before I got some of these tubes to try, I did not know what to expect, and in truth was slightly suspicious of them. I have lots of the worlds great output tubes in my collection including Sylvania, GE, RCA, Genelex, Tung-Sol, as well as several of modern and recent manufacture. There are several important tests that show ultimate performance quality: Pull-down voltage(the ability to turn-on perfectly at maximum drive), maximum voltage swing into varying loads(the ability to drive difficult speakers and a measure of its power output vs load response), maximum possible output current, distortion (a measure of linearity), I could go on and on, but against ALL the parameters that I hold dear, Mike's masterpiece performed as follows: Pull-down, 48 volts (the lower the better), max current,0.68 amperes, linearity, 1.2%. Most of the other NOS tubes performed close to, if not quite equal to these. The most interesting comparison was the original British Genelex against these: Pull-down,48 volts, max current,0.68 amps, distortion, 1.3%. The sound? Well, that has as much to do with the circuit the tubes are used in - probably more - than the tube itself. Bottom line, these are great tubes equal in EVERY way to the original British versions. The only thing I can't know about is will they last 50 years? Here's hoping! Thanks for asking a super question, Bob Carver
Q: Hi Bob, Beautiful amp, fine construction, great parts! Glad to hear you will build custom amps! No real hurry, but I've been thinking I would like a stereo tube amplifier with a bit more power, maybe using 8 KT88s (maybe 6550s would work, what do you think?) per channel, a good sized power supply sufficient to more than handle the draw without sagging. Probably have to be on three chassis. I would like it to be able to handle 2 ohm speaker impedance (for, as you mentioned, those speakers with difficult loads). Not having to replace tubes for anywhere near 50 years would be great, too! Jan-01-10
A: Hi 'center, Bob's my name, and amps are my game!If you're looking for power, you've come to the right place! How much power are you thinking? Warmest, best and happy new year. Bob Carver Bob Carver
Q: Hello again, I will be happy to e-mail some pictures to those that would like to see the finished product. Bob I will ever be grateful to you for your patience, understanding, your much needed expertise in building a pair of amps that are second to none and a dream come true. You have shown me that you are a man of your word and there is no doubt in my mind that what you say about your amps would be true and more. Best of Regards, "jay" Jan-01-10
A: Hi Jay, Thanks again for the accolades. Bob Carver
Q: Hello Bob, a year ago you promised to send me a schematic of the amps you were selling on E-bay you not only kept your promise to do that but you had upgraded it especially for me so I could use my Acrosound TO-330 output transformers and Genelex KT-88 Gold Lions tubes, you also spent one of your Sunday afternoons designing a special power section so I could use the big power transformers that I already had. Phone calls and many e-mails you guided me through the process of building the amps, and the results of this is a pair of amps that sounds stunning! Wow!!! The mid-range is like liquid honey, crystal highs that Memorex would love, lows you can feel deep in the soul, and the power output seems almost unlimited a sound that I can't stop listening to. I will be happy to e-mail some pictures to those that would like to see the finished product. to be continued in next question and answer, see below. Jan-01-10
A: Hi Jay, It stirs my soul that you built it from my schematic and got it to work so well! glad you like the results, and I'm sure that building it was an awesome adventure. Warmest and best, Bob Carver.
Q: Bob, One more question.... my preamp has balanced XLR output. Can the corresponding input be added to this amp ? Jan-01-10
A: Hi '52 again, Others have asked about adding an XLR, and unfortunately the answer is no. Vintage gear has always used standard RCA inputs, and besides, I get great sound from these input configurations. I use it exclusively throughout my own system at home; There is ABSOLUTELY no advantage to XLR unless your system is picking up hum from a long cable run. Hope this helps '52ever, Bob Carver
Q: Bob, You stated these amps have different tubes than the last set... Are they better , worse ? What is the difference? Also could you explain "Scintilla drive capable". Thanks One more ... would you consider making a pair on order rather than putting them up on eBay ? Sometimes the bidding can get out of hand. ( I know that is good for you) Thanks Again and Happy New Year Jan-01-10
A: Hi 'ever, This amplifier pair has Gold Lion KT88's, whereas the the last amplifier had Silver Eagle KT88's. One set is not better than the other. Historically the Gold Lions were designed to go with the Partridge output transformers, and I optimized the Silver Eagles for my original output transformers. That's the main difference. Scintilla drive capable simply means the amps can drive one ohm, the impedance of the Scintilla loudspeaker. Since it was designed to drive one ohm with about 20% current to spare, it can also drive other difficult to operate speakers. As for making an amp to order - I need to ask Tubular Joe if he would consider building a set -I don't see why not, but for the moment these amps are e-Bay amps. Thanks for the two very interesting questions, Bob Carver
Q: good morning Bob,just a short note,i spent a good part of iast night listening to my new amps,there a dream come true,didn't know what i was missing all these years.a slap on the back is due whoever packed them,traveled 3000 miles without a hitch,great job.your new amps sound promiseing,maybe i can make them mine also,maybe not we'll see,thanks again,Robin Dec-31-09
A: Hi Robin, Wow! Thanks for letting me know how much you like them and for making my day. I bet when you won them last auction you never thought you might bid for these new ones this auction too. Thanks again, Bob Carver
Q: Hello Bob, I know its you because you gave us your Dogs last name - And I know your Dog well! Question now: If I am the winner (I will try) Will you get a Picture of you signing them (Digital) and email it too me? Best Wishes & THANKS!!! Dec-30-09
A: Yea '500gt! Bob Carver,
Q: Hello Bob, I just wanted to state that I believe you should put your last name in the main heading of this listing. Not that I could afford these right now, but I did a search on Carver Amplifier and this was not in the listing. With your name in the listing I think you will get alot more views and maybe more bidding. I have one of your older amps that I love and I wish I could afford these beauties! Anyways good luck. tom Dec-30-09
A: Hi '420, Thanks for your passion and thanks for writing. I know...... it's hard for me to figure out what to put in the main heading. Not enough room. Oh well, perhaps I'll try next time. Good idea, thanks again, Bob Carver
Q: Hi Bob, Would these 130W amps make my Plats sound as good as the 180W amps you brought to the fest year before last, or do you think they would be a little light on power? Thanks, Skip Dec-30-09
A: Hi '52 again, Well, for a variety of technical reasons, 130 watts of tube power is about the same as 200 watts of transistor amp power, so unless we are bugs-in-our-teeth crazy for SPL, I think these will play loud enough for normal, rational listening. It will be close though, as the Plats are only 96 db SPL per watt. Thanks, Bob Carver
Q: The amps ending Dec. 13 also states that "the last pair" of Partridge transormers were used. Did you find more? I am local and would love to listen to them with the Scintillas. Any chance of an audition? Thanks. Dec-30-09
A: Hi 'er, Not yet, and the ones that were Scintilla drive capable are no more. I'm trying to copy them, but so far without success.I would be delighted for you to come over for an audition with the Scintillas as soon I find a new transformer. Hope this helps, thanks for writing, Bob Carver
Q: Hi Bob, Its me, Frank from Manahawkin NJ. Another nice beauty, Remember I had asked if you could send me a schematic of your new amp design, my email is ferdin@verizon.net I was also interested if you had given anymore thought to making your own OPT's. I thought your last amp was THE LAST, but I see you have another one. Or were you able to source opt from a manufactuer that will work with your design? I have been tweaking my newly built KT66 PP with 6cg7's and have improved it so much since its first trial that it will now out performs the McIntosh MC30's in power output and quality of sound performance. Especilly in the bass department. I have MC30's here at my house for the A/B test. Its the best Kt66 I have made so far. Now I want to do a stereo version on one single chassis. Well I dont want to take up anymore of your time. If you dont want me see the schematic, just tell me and I will stop bothering you, although I will still send you nice comments on your beautiful amps. Thanx Dec-30-09
A: Hi 'frank, Thanks for sharing your Kt66 story. I'll trade you schematics. So far no luck in copying my earlier output transformers,but the future lies ahead and my effort is not over yet. Just kidding about the schematic trade, you don't need to send me yours, though I WOULD love to see it. I would be happy to e-mail you a copy, but you need to e-mail me after the auction so I will not forget. bob.sunfire@gmail.com
Q: How would you characterize the frequency extension of these amps, bass impact and control, and treble? Also, I don't see a lot of capacitance compared to some other amps, can you comment on that? Thanks, Pete Dec-30-09
A: Hi Pete, The impact, control, and extension stand side by side with the greats.Superb. As far as capacitance goes, this amp has about ten times more than any vintage amp I know of, with 700 joules of energy storage. Perhaps you meant driver capacitance, in which case the exact values are chosen for low-frequency loop-gain stability, and are related to the maximum volt-amp signal delivered to the primary of the output transformer. There is an optimum value for this,rather than "more is better"; the exact value is steeped in loop-gain and feedback theory. Hope I did not put you to sleep - great question, Bob Carver
Q: Hi Bob, do you agree with Julian Hirsh that the Partridge transformers (in your new amplifiers), are arguably the best in the World? Thanks, Alain. Dec-29-09
A: Hi Alain, They are absolutely ONE of the best in the world. No doubt about it! Their sound is ledgendary,they are wound like no other, and possess a power bandwidth that was,and still is to this day, a minor miracle. Thanks for writing, Bob Carve

Question & Answer Answered On
Q: Hi Bob, do you agree with Julian Hirsh that the Partridge transformers (in your new amplifiers), are arguably the best in the World? Thanks, Alain. Dec-29-09
A: Hi Alain, They are absolutely ONE of the best in the world. No doubt about it! Their sound is ledgendary,they are wound like no other, and possess a power bandwidth that was,and still is to this day, a minor miracle. Thanks for writing, Bob Carver
Q: Sorry not about this item. Do you ever build 10 - 20 watt 300b sets? Dec-28-09
A: Hi 'james, That's really a great question; it leads me to talk a bit about what I think is important in amplifier design. long ago, when amplifier design was in its infancy, designers were trying with all their might to eliminate both crossover and notch distortion in push-pull output stages. Success was almost impossible back then without resorting to impractical, heroic efforts. Single ended output stages were the only way that a practical output stage could be designed that was free of notch distortion. The problem was with the output transformer; something called leakage inductance caused a fly-back voltage to appear at its output,resulting in an aweful "snapping" sound for frequencies above about 3kHz. And so the class A,single ended output stage was born for everyman's amplifier. As time and history marched on, designers were able to eliminate the problem. Advanced winding methods and geometry, along with new steel for the magnetic circuit allowed a complete elimination of the problem to the point that today, push-pull circuits have far less distortion of all types than single ended ones can ever hope to have. That's not to say that single ended circuits can't sound wonderful and romantic with their sweet and juicy like these nutz. even order distortions - they do. But so can powerful push-pull designs. So.....I really don't like single ended amps, they just don't have enough power for me, and I have tried them over and over again. My amp has a switch that allows a reduction of feedback and an increase in the romantic distortion components for any of us who like it that way. The notch problem has somehow remained in our minds from the past, even though in reality modern transformer design has eliminated it. Good designs are totally free of it, and are smooth and linear with no trace at all of the old notch distortion! Thanks for writing, Bob Carver
Q: Is this the same item that ended on Dec. 13th ? Dec-27-09
A: Hi '52, Read on for the answer - but in a nutshell - no. Hope this helps - I probably should change the way I take the pictures, but I already have a little place I made for taking them. Someone once told me "If it's not broken, don't fix it." Thanks for writing, Bob Carver
Q: Is this the same item that ended on Dec. 13th ? Dec-27-09
A: Hi '52, Read on for the answer - but in a nutshell - no. Hope this helps - I probably should change the way I take the pictures, but I already have a little place I made for taking them. Someone once told me "If it's not broken, don't fix it." Thanks for writing, Bob Carver
Q: Hello Bob! More of a statement than a question. I just wanted to thank you for your help in getting my Sunfire back to spec. I am happy to share with everyone here that when you promise to be there for someone if they ever need your assistance in fixing one of these amps that you are indeed a man of your word... Any plans of offering a matching preamp to go with these amps? How would you compare them to the legendary Carver Silver Seven Tube Monoblocks? Dec-27-09
A: Hi 'ohn1, Thanks for your kind thoughts, and yes, I'll fix them free,even the tubes,as long as I'm alive. As for these amplifiers vs my Silver Sevens, that's like asking a parent which child he/ she loves the best. I love them both. Each amp has its own personality - each true, but each unique. So we see that children and tube amps have something in common. Thanks for writing, Bob Carver
Q: Did I see this auction awhile back? Thanks! Dec-27-09
A: Hi 'triump, Thise is the first time this auction has run - you probably saw one of our earlier auctions for amps that looked almost like these. The earlier amps all had Silver Eagle output tubes where these have Gold Lions, as well as Partridge output transformers.Hope this helps clarify, Bob Carver
Q: Hi, How would I know this is real and not a scam ??? Do you have a buy it now price ? Dec-27-09
A: hi '52ever, I know it can be hard sometimes to know a scam, even looking it in the face. Oh well, you can ask me a question for which only I would know the answer - like my dog's last name. Or a complex tube amplifier question. See, it's really me, Bob Carver
Q: Beautiful amplifiers! Merry Christmas Bob Dec-26-09
A: Hi 'soundz, Thank you. And merry Christmas tooo yoooo! And a happy,happy new year too. I'll answer all the other questions sent in after today. Warmest and best regards, Bob Carver
Q: Hi Bob - I own some of your classic gear - Phase Linear 400 amp and SD/A-490t CD player. The PL carried a DJ biz I had while in college during the late '70s to early '80s. Question about these monoblocks: I notice similar (if not identical) components, yet this current set has a lower output specification from the prior example you auctioned. Will you please explain these apparent output differences? Thanks! --Scott. Dec-24-09
A: Hi Scott, It makes me feel nice and warm inside that you remember, and actually own some of my classic gear after all these years. Yea! As for the power specification - it's related to the Partridge output transformer, which has a slightly different turns ratio (primary to secondary) than the output transformer I used on the other amps. Designing and winding output transformers is at least 40% art, with only the rest science. However back when the Partridge was invented by one A.N. Williamson(a true genius),it was probably 90% art. But even back then, the laws of compromises and trade-offs were the same as they are today. He traded maximum output power for a wider power response. A good trade? Perhaps. You decide. His results were superb, and he has gone down in history. Hope this helps, Bob Carver.

What follows below is the Q&A section of Bob's tube amp auction that ended 12/13/09. One of the questions contains a web address that Firefox flags as possibly hosting malware or is a forged site. I suggest exercising caution should you wish to access that address.

The final sale price was $6975

Q: hi I am very interested in bidding on the amplifiers. How ever I wanted to check to make sure to would be okay to submit payment on wednesday......Pending I win the auction please let me know Thanks Robin Dec-13-09
A: Hi Robin, No problem, no worries. Wednesday or even Thursday would be just fine. Hope this helps, Bob Carver
Q: Hi Bob, I am currently am running B&W 800Ds with Audio Research REF5 and LAMM M1.2s REFs... How would this work in my setup (in place of the LAMMs)? Dec-13-09
A: Hi '3xud, I'm assuming you're running your Lamm M1.2 on the bottom and your AR on top. If that's the case, then you have 120 solid state watts for the bass frequencies. More power would almost certainly give you better bass. Here's what I would try as an experiment (to find out). Temporarily reverse your amps with tubes on bottom and transistors on top. This will allow you to hear the characteristics of a tube amp with its impedance tracking ability for the low end. You won't be able to play it very loud, but that's okay for this experiment. Pay attention to the CHARACTER of the bass, and read my other answer below for a scientific discussion regarding the advantages of tube amps for bass PROVIDING (!) they possess high current drive capability. Bottom line - no pun intended - is that these amps would be better for your low end than the Lamm. And I could be wrong. Hope this helps, Bob Carver.
Q: I was ready to bid on your auction, when a friend showed me this forum: http://ws1.chitose.melsa...community/eBayShowBlog/ People say bad things about you. Are you an honest seller? Dec-13-09
A: Hi '1987, I tried to get to that forum, but could not - probably because I pushed a wrong button somewhere. Anyway, I'm sort of used to people saying bad things about me, even though I try to be a powerful force for good in our audio world. Oh well, at least there are lots who say good things about me; way more than the bad stuff, fortunately balancing the bad stuff all out. If I took it in, I'd drive myself crazy. So I just remember the good stuff and stay sane. And yes, I'm an honest seller; I'll even fix my amp free as long as I'm alive, even if it means replacing all the tubes. An easy promise - the chances of that are almost zero - everything would have to break all at once! If you want to test if it's really me here, ask me a question that only I would know the answer to. Like my dog's last name. See, it's really me! Warmest and best regards, Bob Carver
Q: Dear Bob, sorry for asking question which is not regarding the current amp you are selling. I have your solid state Carver Research Lightstar Reference power amp from 1994. As there are several probs with the device, I want to ask if you could kindly send me a service manual. I could pay via paypal or any other option you would prefer. Many thanks in advance! Kind regards, Max (+7 495) 518-1870 Dec-13-09
A: Hi Max, I would be happy to send you a schematic. I tried calling your number but could not reach you. Call Rita's at 425 530 9557, ask for Rita or Lisa, and I'll ask her to send you one. Also please send them your e-mail address. No charge, the schematic is free. Hope this helps, Bob Carver
Q: Hi Bob, Ed again, I currently run a pair of Thiel CS5is through a pair of Krell KAS 2 class A mono blocks and am just wonder if your amps would be able give it the tube soundstage without sacrificing the bottom end? Thanks. Dec-13-09
A: Hi Ed, For a variety of technical reasons, tube amps are able to deliver a beautiful and enveloping soundstage like no other. They also will have a bottom end that's more powerful than a solid state amp IF - and here's the caveat - they ALSO have a lot of current drive capability. Now, all cone based loudspeakers (including your Thiel's), have an impedance rise in the bottom end, and a tube amplifier can easily follow this rise because of its internal generator none-zero output impedance. A transistor amp usually has an internal generator impedance that approaches zero, so its drive can't follow that impedance rise. So far so good. But what goes wrong with all this in the real world is that tube amps almost always becomes current starved when trying to deliver intense low bass. That's where solid-state amps have an advantage, usually outweighing the intrinsic bass superiority of tube amps. The only way I know of to have my cake and eat it too ( besides forgetting some of the lessons my mother taught me), is to design a tube amp that has enormous current reserves. I did it on purpose with this amp by using twelve mighty KT88's in the output section, by operating their screen (grid #2) connections from a separate high voltage power source, and finally, by use of a DC restorer. This amp can deliver over 24 amperes and 300 watts into one ohm. With speech and music waveforms, that number becomes a whopping 450 watts into FOUR ohms with all the current we could rationally want. Better than all but the biggest solid state amps. Have your cake and eat it too - tube amp soundstage with low frequency bottom end impact and slam. Great question, Bob Carver
Q: Hi Bob –Its straylight, I bought the 4th pair amps in Dec 2008, item #180315426456 including Citation I preamp that you rewired to create a moving coil input for me! -one of a kind! Bob, shortly after our last call I was diagnosed with a life threatening disease and although my prospects for surgery in January look good there are no guaranties in this life. It also makes having listened to your 180 mono amps over the past year all the more special. Your amps have been a true inspiration to me and your auctions are the best educational tool on ebay! After you and I leave the ‘stage of life’ your amps will go on to inspire a whole new generation to say "what a wonderful soundstage", "what was Bob thinking when he designed these?" Since we may never know exactly it only depends the mystery & charm of these wonderous audio creations -the best I've ever heard in a lifetime! Thnks for bringing these amps into the world...it has helped me focus on what's important in the remainder of my life Dec-12-09
A: Hi Straylight - Your focus on the important things is going to last a long, long time to come; there are no early outs for you or for me. Not yet. You'll see. I'm calling you after January so I can watch over you and thank you from the bottom of my heart for your inspiring message! Bob
Q: Mr. Carver...I am listening at this very moment to a Carver 390t tube CD player, and an M400a 'cube' running a pair of Maggie MG1c's....and LOVING THE SOUND! I've been a fan since acquiring the M400's a few years ago. I need though to get enough juice for a pair of MG3a's and I previously used a pair of the M400a's bridged to mono but soundstage collapsed beyond my tastes when bridged. ***Will your new amps have similar characteristics?*** The Maggies reveal everything and need plenty of power. 500wpc is not TOO much if it's clean. Dec-11-09
A: Hi 'st, Oh man, you are making my day! It's fun to hear about your M400 still making music after all these years! As for these 180's, since they are tube amps and have an output transformer with taps that will step up their output voltage, bridging them would be redundant and unnecessary. Regarding their soundstage presentation - that's one of the things big tube amps do best, building a soundstage, and with beautiful imaging inside that big soundstage. Great comments, thanks for writing. Bob Carver
Q: Hello Bob Could you email me the dimensions of the amps please as i have two amp stands and would like to know if your amps would fit them. Could these amps be picked in person as i live in Vancouver B.C. Thank-you Ken Dec-10-09
A: Hi Ken, 12 1/4" wide X 14" deep X 7" high. Plus the height of the feet = 0.5". Plus the terminals on the back stick out ~ 0.8". I spent my first year in grad school at the UBC right there in Vancouver, and have many fond memories of my time there. I'll go you one better - I would love to drive around my old campus from so long ago, so if you win our auction, I'll deliver them myself, help set them up, take you to dinner and talk into the night about tube amps. Thanks for writing, Bob Carver
Q: Hi Mr. Carver, It's both a pleasure and an honor. I wish I had a disposable income at this point that enabled me to snap up this last pair of amps, but I do not - short of winning the lottery Have you made any progress in cloning those unique transformers, or is this the last pair of amps that will feature these wonderful characteristics? Of course, I ask because I am also an Apogee owner that wants a tube amp that can "deliver the goods" with whatever Apogee model I choose. I have owned Scintillas, but sold them due to economic considerations, and now own a pair of hybrid Centaurs. Thanks for your time. rube Dec-10-09
A: Hi Rube, Oh well, maybe you WILL win the lottery, or the Irish Sweepstakes - I'll be keeping my fingers crossed. As for output transformer progress, I've been too busy of late to start the project as clonemaster for these transformers, but I will start soon. The biggest Apogees were the most difficult to drive, and I must commend Jason Bloom for designing them HIS way for the best possible sound, allowing the impedance to fall wherever it needed to be to get the perfection he wanted. That takes a great deal of courage in the face of practical issues, such as getting the speaker to work with normal amplifiers. I too am an Apogee lover - that's exactly why I had to make this tube amp operate into one ohm. Thanks for writing, Bob Carver
Q: Hello Mr Carver! Beautiful amps! And I have three different pairs of Apogees, among thme the Scintillas; that that I’m sure would love to be powered by these babies. I am however a european resident. Can they be rewired for 220V? Can you ship to Europe? Best regards, J Dec-10-09
A: These amps do LOVE Scintillas, and they can easily be wired for 220V, as they have a split primary designed just for that purpose. And yes, I can ship to Europe by using technology from the Cross Oceanic Shipping company, Boeing, or Airbus. Bob Carver.
Q: Hi Bob, Are these only wired for 110v only? Does the transformer allow for a 220/240v tap? Thanks Regards Ed Dec-10-09
A: Hi Ed, The power transformer has a split primary, allowing it to be wired for 110/120 or 220/240. The changeover is easily done by you, me, or a qualified technician. Thanks for asking, Bob Carver
Q: Hello Mr. Carver, it's a pleasure to see another one of your beautiful amps. Would you be so kind as to email me a pic of the rear and a schematic? I don't want to assume all the large brown caps are coupling caps. Viewing the minimalistic design, I feel like a curious kitten. I'd also like to know the dimensions. In regards to specs, I've had input impedance issues with a Cary product that resulted in poor input sensitivity. What would you recommend for these amps? My tube preamp specs are Gain= 18.5db, Output Impedance= 40 ohms, and Max output= 40vrms. Hopefully my preamp will like these amps, and I'll be warming up my music room and spinning my vinyl with these. Looking forward to your answers. Best Regards, Werner. Dec-09-09
A: Hi 'samx, I would be happy to send you a picture and a schematic. I need your e-mail address; please send it to me bob.sunfire@gmail.com On another note, the input impedance of this amp is 100K ,and its gain is 30dB. That means it is perfect for your preamp, as the loss would be 0.0035 dB - nothing! And with 18.5 dB gain from your preamp, you will have all the drive you could ever hope to have. Thanks for the questions, Bob Carver
Q: Are you using a negative feedback to stabilize the DC? I notice you have this in some nice wood chassis or maybe it is metal. I found this stuff called MuMetal. It is expensive, but I use it in high end guitars and amps for use on the stage where lighting and other stuff wreaks havoc with EMF and 60 Hz hum. I would really like to know how you have balanced the DC on this. What did you use as output transformers? Are they old vintage or custom wound? I find some of the older stuff is not consistent. Key word is SOME. 1 ohm tap!?!?! I see that very rarely, and not usually on tube amps. The sound through a 1 ohm speaker(s) is very detailed and sweet and juicy like these nutz.. I wound guitar pickups custom on both a couple home made hand machines, lead screw guided machines, and the famous Leesona (POS). I am looking into financing a CNC cutter for core laminates and a Chinese made CNC lead screw machine that supposedly will handle up to #6 AWG. I am super curious. Contact me. God bless you 2! Dec-09-09
A: Hi 'moeddie again, Since this tube amp has an output transformer, and all its feedback is taken from the secondary winding, there can be no DC feedback. That's because a DC signal cannot be supported at all by a transformer. It would have to be infinite in size - that's bigger than the universe is large - 15 billion light years to its visible edge. Though this output transformer is massive, it's not quite that massive! The output transformers are very vintage, not custom wound, and each possesses a split bifilar wound secondary. Hence the one ohm tap, which emerges quite naturally by wiring the secondary half up, half down. Viola' - one ohm and 305 watts, thanks to the DC restorer and six KT88's. As for Mu-Metal, it's great stuff, expensive as you said, and normally restricted to very small amounts where low level signals need to be well shielded - as in guitar and vinyl phono pickups. Hope this helps, Bob Carver
Q: I do work for a man who owns a used car dealership that deals in high end cars. They are status symbols but they go down in value faster that they can go down the road. He has a small museum of old guitars and amps in an old courthouse in upstate NY. I do lots of repairs and try like anything to use Astron caps, or whatever was original, or just use good stuff and keep the old parts (always keep the old parts in a bag). I would like more information on how you stabilize the DC from drift and shift as I call it. Either it is drifting around, or sometimes it will just shift from a reference point suddenly. My utility power quality is perhaps the worst in any large urban setting. We had 62 MPH top wind gust at 23:07 Mon night. The top recorded was 74 MPH. 250,000 people lost power. I have had 83 interruptions since 21:30 Mon. There are spikes, sag, noise, and even freq drift of >10%. I run through a UPS and iso trans just so I can work. I'd love more info on this. Dec-09-09
A: Hi Satchmo, Well, I hope these amps don't go down in value as they get older. I hope they become classics down the road and GROW in value because they sound great, as well as becoming (in time) vintage. Now that I think about it, they already are vintage because of all the vintage parts inside. The DC shift is eliminated through the use of several things: one, about ten times more energy storage than vintage classics used, two, balanced long-tailed voltage amplifiers from the input stage through the output stage, and three, the use of a 6AL5 DC restorer to restore the lost DC value of the signal as it propagates from input to output. These three things combine to reduce idle power dissipation, harmonic and IM distortion, and best of all, "drift and shift". With this amp you won't need a UPS and an isolation transformer at all! Bob Carver
Q: Any pictures of the rear panel of the unit??? Regards, Warren Galliano Dec-09-09
A: Hi 'ianno, I DO have a nice picture of the rear panel, but I don't know how to post it here without starting my auction over. That's because I already have the picture limit posted, according to the eBay help line. Looks as if I goofed up at the start of this auction. What's your e-mail address and I'll e-mail the picture to you. Bob Carver
Q: Hi Bob, I spoke with you last year about your new amp design. You had offered to shoot me some information on the design schematics. I never had a chance to follow up with you and I lost track of your ebay name. I have built a couple of amps this year based on the Williamson design using KT66's with 6CG7 drivers and Heathkit iron. Not a bad sound at all to them! I would love to get a look at your new amp circuits if it is still Ok with you. Thank you for helping me out if you can! Frank Erdin New Jersey Dec-09-09
A: Hi Frank, There is nothing more fun than building tube amps, and the Williamson circuit is a true classic that would bring lots of pride in a personal home built unit. I'd be glad to e-mail you a schematic, just give me your e-mail address and I'll send it off to you this evening. Bob Carver
Q: Hi Bob, can you tell us a little about your Scintilla speakers? Original ribbons? Modifications? Did you own other Apogees as well? Thanks from a former Carver amp/preamp owner from the past as well as a current Scintilla owner. Dec-09-09
A: Hi 'ale, I bought them many years ago from a Carver dealer here in Seattle. They are the original ribbons, with no modifications, and yes, I owned several other smaller Apogees around the same time as I owned these. I can clearly remember thinking - "I am truly in the presence of a great loudspeaker, maybe even the greatest." - when I first listened to the Scintilla. On another note, I hope your Carver amp found a happy home, even if it's no longer driving Apogees. Bob Carver
Q: There's always more transformers somewhere and fabulous things to design! Dec-09-09
A: Absolutely! But sometimes with a hitch. I bought these output transformers long ago when I was a freshman in college from a surplus place in Los Angeles. I've finally gotten around to looking inside one of them - my last one - and it is built way to expensively and beautifully to be a commercial transformer; it is clearly a military spec transformer, probably built in a time when output transformer design was far more artful than it is today. There is none that can compare, as far as I know, and I'm not exaggerating. As I see it, my job now is to figure out how it was built in every detail. Then I can clone it. Bob Carver
Q: Hello Bob Thought I would use this way to say g'day to an unlikely Ap' owner as I don't have an email address for you! That valve amp looks FANTASTIC!! Bet it could solve a few of my clients "problems" Take care - Graz info@apogeeacoustics.com Dec-09-09
A: Hello Graz, Thanks for the accolades. I think they look great too, but then again I designed 'em so I was prejudiced to start with. Still, I must say they operate my Apogees beautifully; it's that one ohm tap and the six mighty KT88's. My e-mail is bob.sunfire@gmail.com Bob Carver
Q: how many pairs have you made and how many more can you make like these , these look so nice BOB , good job ,very classy thanks kevin Dec-09-09
A: Hi '739, I have not kept track all that well, however I think five pairs to date and auctioned on eBay. I'm out of these great output transformers now(except for one lone unit), so I cannot build any more amplifiers like these unless I clone the transformers. However I do have my old transformer winding machine left over from my Silver Seven days, and if I get lucky enough I'll be able to use it and make a close facsimile. Thanks for the appreciation Kevin, it took me some time to find just the right color - it came from an old '56 Chevy I had as a teenager. Metallic strawberry burgundy. Bob Carver

Q: Hi Bob, How would these compare with silver 7's? Dec-07-09
A: Hi 'rc, That's like asking "Who do you love the most?" I love them all - each has a distinct and different personality, unique and beautiful, but different. Children and amplifiers share SOME things in common. My Silver 7's are not to be believed, they are so good. - I didn't say it - many others did though, and these new mono- block amps are designed with Tim's and my latest thinking. I love them both!
Q: Good Morning Bob, I'll change my name to Skip if you want to send those "Babies" to Oklahoma, serously tho, the new color scheme and the meters make me want to stand up and take notice, you have another winning pair there. "jay" Dec-07-09
A: Hi 'music, If you changed your name to Skip, the amps might just skip right past Oklahoma on their way to audio Nirvana somewhere beyond Beethoven's 9th. But then again, perhaps not. Bob Carver
Q: Wow! Sounds like some real schmoes out there just using your photos and such. Knowing Ebay I bet they do little about it. Dang! Dec-04-09
A: Hi 'tube meister, It's extremely frustrating - I have tried repeatedly to put an end to it but found it impossible so far. In all fairness to eBay, I don't think they can do much either. So I'm left with posting WARNINGS wherever I can. If any reader knows of anyone being cheated by this fraudulent offer, please let me know right here on the eBay forum. If it occurs in this country, I have a good chance of stopping it and probably even getting the victim's money back. Bob Carver

From Bob's tube amps sold on 10/30/09:

Q: What about the picture of the rear panel? Oct-27-09
A: Well, I tried my best to get it up, but the help lady for eBay said that since I already had twelve pictures, I was stuck. So.....I'll use words. The back panel has a gold RCA input jack, two fuses, one for AC and one for the tube cathodes, a beefy line cord (see photo), a power switch, a flush mounted bias adjustment, four big terminal binding posts for the speaker, one black, three red, one ohm, four ohms, eight ohms. The back panel color is red, same as the rest of the chassis. Hope this helps, Bob Carver
Q: Hi Bob, Lasareath here from the Polk Audio Forum. The Amps look so nice! Do you have any pictures of the rear panel? Thanks!!! Oct-27-09
A: Hi Lasareath, yes I do; I just forgot to put it up with the other pictures. I'll see if I can add it at this late date - give me a couple of hours from now and check again. It's a great shot. Thanks for the reminder, and keep your fingers crossed that I can add it. Bob Carver
Q: Bob, what preamplifier would you suggest for your amp? Oct-27-09
A: Hi '871, I have several favorite vacuum tube preamplifiers, including the ones I designed. Just the same, for this discussion never mind those. Ahh, but for classic vintage tube units, my favorites are the Stu Hegeman designed Citation I, and the Tim de Paravicini designed EAR. Tim's has a beautiful as well as the quietest MC phono stage in the world, and Stu's masterpiece has wonderful tone controls and a spectacular sounding MM phono stage. If you have a moving coil cartridge and one of Tim's MC transformers, I would mate it with the Citation I and live forever in audio Heaven. Otherwise I would choose the EAR. When I was in hi-school, I had a job at a local Hi-Fidelity store called Seattle Radio Supply. We carried McIntosh, Marantz, Fisher, Scott, Citation, JBL and several others as well. I was allowed to take home as many as I wished, try them out and report my findings back to my boss. It was during that summer that I developed my preferences, and since EAR did not yet exist, my favorites became, in order, Citation, JBL, Marantz, Fisher, McIntosh. I was very young of course, but with all those superb units, I was truly able to stand on the shoulders of giants. Hope this helps, Bob Carver
Q: Hello Mr. Carver. Is it possible to have these amplifiers converted over to 240v? If so, what would the cost be? Thank you for your time, Fritz Oct-25-09
A: Hi Fritz, The cost is free, and yes it is possible. No problem at all, and the best part is that it can be done here in my laboratory or by you (assuming you know how to solder with a soldering iron). Or by a qualified technician. Good question, thanks for asking - ummm, I think I already answered this question. Oh well, twice never hurts. Warmest and best, Bob Carver
Q: Hi Bob this is Eddie from Carverfest! I have to say you outdid yourself on this pair Bob they look sweet and juicy like these nutz. and I know they will sound as great too! Best wishes Eddie! Oct-25-09
A: Hi Eddie! Thanks for the thumbs up - I found some vintage meters on eBay and a new paint color extremely close to the metallic burgundy cherry red I have had in my head for all these years. Thank all you guys for doing Carverfest - I sure had a ball. Bob Carver
Q: Hi,,Do you ship t6o Thailand? Oct-23-09
A: Hi '97. Yes I have the technology to ship these to Thailand. However I get help from Boeing, Airbus, and Overseas shipping inc. And of course the customs folks. Cost would be $516 dollars for both amplifiers. Hope this helps, Bob Carver
Q: Hi, Bob. Do you build single end class A integrated amp with EL156/KT88/6550 (240VAC) compatible? How much would it cost with shipping to Singapore? Best regards John Oct-22-09
A: Hi John. I don't specifically build a single ended unit, however this amplifier may easily be configured for single ended class A operation if desired. And with six KT88's, it would be the most majestic of all SE amplifiers! If you join the bidding and win my auction, I would be happy to make the conversion for you special. Of course you would still need a separate preamp. As for shipping and to Singapore, it would be $256 dollars for each amp. Hope this helps. Best wishes and warmest regards, Bob Carver.
Q: Hello Bob, I just had to write and say "your amps just keep looking better", cool meters!!!, I like them. The best to you, "jay" Oct-21-09
A: Hi Jay. Thanks for the accolade - helps make my day. I like the meters too - I found a stash of these vintage meters on eBay and thought WOW!would they ever look cool on a cherry red amplifier. Glad you agree. Bob
Q: 1st off I would like to say hello, and that it is really great seeing you getting back into tube amplifiers again. My first question: Is it possible to have these amplifiers wired for 240v if I were to win them? Second: would you mind explaining how your DC Restorer works please? Thank you for your time, and I look forward to hearing back from you. Warmest regards, Fritz Oct-21-09
A: Hi Fritz. Yes, the unit can be wired for 240 volts - it has a dual winding power transformer for that purpose. It's a standard and easily made changeover. As for the DC restorer, first a bit of history: A class AB amplifier works by having the positive part of the waveform amplified by the top output tube, and the negative part by the bottom tube. In the case of a sine wave, the positive part is half a sine wave, or HAVERSINE, and similarly for the negative half. During the hand-off from positive HAVERSINE to negative HAVERSINE, that is, during the crossover period, the amplifier operates in class A. For the rest of the time it operates in class B - hence AB. Now the top tubes deliver a half sine wave signal to the output transformer, and this half sine wave possesses a DC value which depends on its amplitude. For lowest distortion, the drive signal on its grid should be a mirror image of the transformer drive signal and possess a corresponding DC value. It should be an identical haversine, differing only by the gain of the tube. And the two signals should be in perfect synchronism. Normal practise is to drive the grid with a standard sine wave that is symmetrical about the zero axis, so its DC value is zero. The DC restorer clamps the bottom half of the grid drive signal, thereby imparting a DC value to the grid and simultaneously providing a mirror image of the plate signal. The result is that both plate and grid have corresponding DC values. The best part is that idle power is cut to about one third, distortion to about one third, and finally, NO DC shift! The old way required enormous (by my standards) idle power in order to overcome or minimize these problems, never properly fixed the problems anyway, and has vexed designers since the very beginning. Often the output tubes were idled right at their maximum possible power rating, or even slightly beyond, often glowing cherry red. They got too hot, and didn't last long. WHEW! I hope you're still awake! Bob.
Q: How in the world do you get over 300 watts out of such a small tube amp ??? Oct-20-09
A: Hi 'i-o, Small? Small! It's big! I just knew someone would ask that, and here is the answer. This amplifier uses the mighty Silver Eagle KT88, and each pair is rated for 110 watts of audio output. Since the output stage is comprised of six tubes, we have 3 X 110 = 330 watts! Beyond possessing the raw power, the output transformer must have the correct turns ratio to deliver it all. The equal windings on this transformer allow a perfect match to either one or two ohms. And the mighty Silver Eagles do the rest. Great question, thanks for asking. Bob Carver
Q: Can you ship to Italy? How much cost? Thanks Carlo Oct-20-09
A: Hi Carlo, Yes indeed I can ship to Italy - I have the technology to do it - actually Boeing and Airbus do, and the cost is approximately $280.00. Thanks for asking and good luck.
Q: Hello! For what sum are ready to sell at once? Best Regards Oct-20-09
A:
Hello Nem'08, No amount, as we want this auction to run its clock down. Thanks for asking though, and if you join the bidding, I'll honestly root for you. Warmest and best regards, Bob Carver.

Not certain where these came from & possibly some repeats, but here they are:

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."

Q: Dear Sir, I am the guy everyone asks to fix things for them. I have tweeked my SS amp as far as it can go and would love to challenge myself with a new construct project like your amps. Living in detroit I find Vintage equipment at hand. So the problem of finding output transformers would be less for me. And I would like to think that they would make a nice match to the pair of Electro Voice Regency speakers I cherish so much. The full upgrade vesion with the T350's, T25's, and SP15's. All 8 Ohm with a crossover made by BEC. Who sells here and can be found on a few of the forums.If I can be included in the Schematics send off I would be honared. repair-tech@charter.net Nov-19-08
A: Hi 'mp, Wow! I'm finding it difficult to believe how many souls want to build this amp. I almost built a Patrician for a friend last summer- T350, T25, SP12 and two 315's per cabinet, but decided to wait 'till next year. Anyway, your answer is yes, just be certain to contact me after this auction is over. I would be delighted to send you the schematic. Good luck! Bob Carver
Q: Can the transformer be tapped for 240volts ac use? Would you consider shipping overseas? I have a FedEx a/c to facilitate this. Nov-19-08
A: Hi 'le8, I CAN make it operate overseas, and yes I have the technology to ship to any place in the world. I'm sure your Fed-Ex account will make things nice and easy, thanks for asking and joining. Warmest and best regards, Bob Carver
Q: Hello- I have a question regarding negative feedback that turns into positive feedback with some circuits. The question was sent to your gmail address along with a diagram of the squealing circuit. Did you get a chance to look at it yet? I am curious as to what I'm doing wrong. Thank you in advance. Blair Nov-19-08
A: Hi Blair, I've been out of town, but I'll find that e-mail and contact you this weekend, or Tuesday at the latest. We will fix it for sure! Bob Carver
Q: Hi, Bob, I am from Hong Kong. Just curious but I am serious, will you and Tim together design and build a power amp best for driving Peter Walker's early QUAD electrostatic speakers, i.e. ESL57 and ESL63. I'll be in the waiting queue. Nov-19-08
A: Hi 'yyu, I'll ask Tim next week when I return home - the main problem is the time it takes to design it AND get it right. Tim and I both have a love for the old Quads - for me it was the first time in my life I heard an amazing speaker. Perhaps we can tap into that old love of QUADS. Keep your fingers crossed.
Q: Hi Mr. Carver, If I won the bid is it possible that you could convert the amp to 220V. I intend to use them in Thailand. Thanks. Nov-19-08
A: I will adapt these amps to operate on 220 volts. No problem. Happy bidding and lots of luck! Thanks for asking, Bob Carver
Q: Hello Mr. Carver, as a vacuum tube amplifier scratch builder and honoured student of Lance Cochrane, I can really appreciate these two massive units you and Tim have created! Very nice to see you enjoying tube technology. To me, it's just so much more fun in every way than transistors could ever be! Also nice to see that Lance had a hand in getting you involved in the ebay experience. You are a very well respected man in audio, and to own something with your name on it is truly an honour! P.S. Just so you know who I am, you recently saw my work on my new web site. Steve- Peterborough Ontario Canada Nov-18-08
A: Hi '748, Steve, I saw, admired your work and completely identified with your passion and creative drive to build something better and out of the ordinary. What better place than in the world of vacuum tubes? Your amplifiers are beautiful; each so unique - seems we were both inspired in important ways by Lance. Thanks for your comments, keep up your good works, Bob Carver.
Q: Hello Mr. Carver, I can't tell you how inspiring it is to see these beautiful amps! I used to design and build tube amps as a hobby in the 60's, and now after 35 years I am back at it again. I am so excited because now we can make them sound even better, and your DC Restorer circuit appears to be a solution to an age old problem. Have you published the details or schematic of your DC Restorer anywhere, or would I be able to get a copy from you? Thanks, John (access_guru) Nov-18-08
A: Hi 'ru, John, I'll send you a copy about a week after the auction closes. I'm out of town right now (on the road) and I'm following our auction from my hotel room. If you contact me later in about a week or so, I'll send the schematic and a parts list. I have to say, there is nothing more fun than building vacuum tube amps. Thanks for writing, Bob Carver
Q: Hi, Bob! I have read in your replies that you can share schematic of this amp after auction end. May I ask you the same favor? Nov-18-08
A: Absolutely! My pleasure. Just don't forget to call after the auction. Thanks for asking, Bob Carver
Q: Dear Mr. Carver, I am very excited to see a pair of amplifiers designed by yourself and Tim De Paravicini. Unfortunately, I am unlikely to be able to afford to purchase them and was wondering if you would be willing to make the schematic available. i would like to try to build a copy for my self if you don't mind , i was allwayes want a amp from you , so i want to ask if teh scematitic is all i need to get help and do a copy regards yehuda Nov-18-08
A: Hi '972, Vacuum tube amplifiers are fun to build and listen to; I'm happy to make the plans available, along with some good tube amp counseling along the way as you enjoy the adventures of buiding a pair. My head is swelling - thanks for the accolades - makes my day! Just contact me about a week after the auction is over to help me remember this promise to you. Thanks for writing, Bob Carver.
Q: Bob, You asked me to ask Ed Dell about publishing the schematic for this beast. [BTW, I changed my EBay ID from "nation_sauna_wholesalers" to this new moniker, "technicalaudio", in case you're wondering]. Here is Ed's reply, verbatim: "Hi Brian Thanks very much for thinking of ax as a path for those interested in Bob Carver's new amp (what a marketing genius he is.) I would be happy to publish the schematic. I would also request permission to use one of the photos he has posted on e-bay (not the one with him eating the apple(or hotdog, however) and also a parts list. He may question adding the parts list since with it people may construct the amp themselves. The smart ones will figure this out without the list, however. This is a great opportunity for us, since every bit of news about ax helps spread the word about DIY. It is nice to have long-term readers who do the creative thinking for you. Thanks Best Ed" (ed@audioxpress.com) I'll let you contact him directly. Thanks! Brian Nov-18-08
A: Hi 'dio, I e-mailed Ed this morning and said I would be delighted to share these amps with his readers, including schematics, parts list , and helpful hints. If he wishes of course, but I have not heard back from him yet. Many years ago he ran the complete plans for my big Silver Seven tube amp, and I actually met several builders who had built them. I couldn't believe it! But it was true! Thanks for the important idea Brian. Best wishes and warmest regards, Bob Carver.
Q: Hi:I'm hoping youall can helpme with my telefunkn fome Belg. Everything is in German.Its a Conceritino#7The 110 side of the power supply burned out. Can you be of some help.Is There an out of the unit(radio) power supply THE 220 WORKS THE TUBES COME ON. .Thank you for time Michael D.Ross (760)672-7515 Nov-16-08
A: Hi birdman, Of course I will help. Contact me about a week after the auction for a scientific discussion about burned out power supplies, and we will almost certainly get your amp up and running. Looking forward to our amplifier science talk, Bob Carver
Q: hello mr carver-- beautiful pieces! wondered if you have considered making affordable tube gear for those lacking funds to own things of this caliber. i bought one of your 400 amps in the 80's and loved it, bought a 400t a couple years ago from ebay and it was awesome as well. currently using a tube amp from a wonderful fellow that sells his amps on ebay from california you may know. i think that you could sell them as fast as you could make them if you had a similar piece with your name on the front. just a thought. again, beautiful!!-- Nov-16-08
A: Hi '914, You are making my head swell a bit. Thanks for the kind thoughts - and if the fellow from California happens to be Lance, know that it was he who gave me the idea of doing an eBay amp - it seemed to be lots of fun meeting so many tube amp lovers. Thanks for writing, Bob Carver.
Q: Mr. Carver: I'm a poor student. Actually, I'm a very good student, but am poor of means. I have always thought highly of many of your products, including the Amazings. I would like to beg a copy of your schematic as well, if you would be so kind. Please put me on your list. Thank you very much. Indeed grateful. --Robbbie Nov-16-08
A: Hi'piv - Robbie, You are on the list! Please contact me after the auction is over to get your copy. I was a broke student too, so I hope the schematic helps you as much as tube amp schematics helped me when I was a student. Best wishes and warmest regards, Bob Carver.
Q: Mr. Carver: I'm a poor student. Actually, I'm a very good student, but am poor of means. I have always thought highly of many of your products, including the Amazings. I would like to beg a copy of your schematic as well, if you would be so kind. Please put me on your list. Thank you very much. Indeed grateful. --Robbbie Nov-16-08
A: Hi'piv - Robbie, You are on the list! Please contact me after the auction is over to get your copy. I was a broke student too, so I hope the schematic helps you as much as tube amp schematics helped me when I was a student. Best wishes and warmest regards, Bob Carver.
Q: Hi, Bob! I have read in your replies that you can share schematic of this amp after auction end. May I ask you the same favor? Nov-16-08
A: Hi'_ba, Yes, I would be delighted. Just make sure you contact me about a week after the auction is over and I'll send it to you. I'm out of town for the next ten days and will be answering questions from afar from my hotel room, but I won't have a schematic until I return home. Thanks for writing, Bob Carver
Q: Dear Bob Carver: I sad to say am in the group that most likely willnot be able to afford the final price of these amps, but must say they are indeed beastiful! (Probably the most beautiful item on EBAY except perhaps the K model Beechcraft Bonanza! Thanks for all thec info I appreciate it Tom Nov-15-08
A: Hi 3550, Tom, Thank you for the accolades, even thought the Beechcraft IS prettier. Perhaps the last sentiment depends on whether we are pilots or tubaphiles that glow in the dark. I'm glad you liked the techno information - I often think I'm putting all of us to sleep when I go on and on with so much technical stuff. Thanks again for writing and for your comments, Bob Carver
Q: Hello Mr. Carver, Im down in Seattle and would gladly come pickup the amps and pay cash to avoid all the PayPal Fee's. Is that acceptable? I did read where you said you would come set it up etc. if the buyer was close. If I win these, They will be put away for awhile until my new home is finished and a large listening room is designed around them. About 9 months out right now. Thank You for your consideration. Nov-14-08
A: Hi '217, So you live in the rain-forest too! Well, if you win, come on over to my place and we can listen here before they begin their long hibernation, to be awakened like Sleeping Beauty with a kiss nine months from now. Best wishes and good luck! Bob Carver
Q: Hi Bob I'm not an audio engineer type,but I love great sound,BTW your amps look great! How come no American Co. has marketed/made affordable great sounding, self bias (for the wider market)tube integrated? China's doing this, I have bought some Eastern Electric goods and they are fantastic, among others, I think there's a market for it here. Still lots of two channel freaks. Any thoughts? Regards,Eric Nov-14-08
A: Hi 'rick, I really don't know why American guys don't build integrated tube amps. Personally I think it's a great idea, and I know that in the vintage days it seems that everybody did. Lafayette, Citation, McIntosh, Fisher, Scott Boulevard and on and on endlessly to name a few. I also know there are lots of us two channel folks. HUMMMM? Bob Carver
Q: Hello Bob I guess you were "just blowing smoke" when you responded to my e-mail promising me that you woulod send me a schematic and pictorial drawing of the last pair of Mono Blocks that you and Tim de Paraficini designed and you and Tubular Joe built) that you sold on e-bay, to use my pair of output transformers Regrds, "jay" Nov-13-08
A: Hi Jay, Man, am I glad you have e-mailed me! I lost you when I had my computer scrubbed clean of viruses by a computer guy. I goofed up. Anyway, now I have found you again and will send you the schematic just as soon as this auction is over. I promise! Please contact me then via my regular e-mail just to make sure I don't forget. You're back! Yea! Warmest and best regards, Bob Carver.
Q: Aren't you the same Mr. Carver that proved that a modestly-priced solid-state amp could be made to sound EXACTLY like any other amp, tube-types included? What has changed? Nov-13-08
A: Hi '618, Yes, it is I, the real Bob Carver. Nothing has changed. What I did at Stereophile so long ago was to show that I could get very, very close. Within one part in better than four ten thousandths, but not EXACTLY. You can read all about it by Googling Carver Audio.com and clicking on "Carver Challenge", or just Google "The Carver Amplifier Challenge" It's surprising to me that after all these years, the article is still being posted in so many places around the world! Thanks for writing, Bob Carver.
Q: NO question, but, as a hi-fi enthusiast who will probably never actually MEET Bob Carver, I wanted to send my kudos to a gentleman who efforts, persistence, and never-ending search for perfection has meant so much to a hobby that so many, of all backgrounds, enjoy. Kudos, Bob. Neil in Kansas. Dec-30-08
A: Hi Neil '43. Who knows what life holds; you have made my day with your kind cheers and nice smile. Happy new year, Bob Carver
Q: any chance of getting, buying or otherwise obtaining a circuit diagram for this fine amp? I am not quite in a position to compete for this amp now. thanks, bob m Dec-30-08
A: Hi sly bob69,I would be happy to send you a circuit diagram. Send me you e-mail and I'll send it within a week of the auction closing. bob.sunfire@gmail.com.
Q: Mr. Carver, I was diagnosed a few years ago at 28 with a tumor on my acoustical nerve. I started to revisit audio shortly after. Being out of work do to my illness I had to sell off my gear. A great friend of mine has been by my side since day one. He put some funds together and got me a new setup. He couldn't afford this but made it happen. Well I had a fire and lost that gear too. so there he and I were with a passion for audio and no gear. "Life goes on".... A short time ago I found out my dear friend is terminally ill. He is bed ridden until his illness takes its toll. Backing up a bit I have spoken to him about who you are and what you mean to the audio world. He called me frantic last night..."get over here man I have to show you something" So I quickly got some shoes on and headed over. When I got there he was literally jumping up and down.. He couldn't show me this auction fast enough. Sure we cant afford these but it didnt stop us from dreaming...Thank you for that. AMAZING! Dec-30-08
A: I am silent, and I'm weeping. What a beautiful story; thank you for sharing it with all of us. Bob
Q: Amps are awsome. I myself also love to design and build tube amplifiers. I would love to meet Bob Carver. Could this be aranged? I would love for him to see my designs and projects. Ron Becker Dec-29-08
A: Hi '32 Ron, I would love to meet and have a scientific discussion about tube amps; there are few meetings that could possibly be more fun! Come on over to my place or to the Sunfire building if you live close by. Or even if you live far away. Bring your designs, I'll bring mine. If you live too far away, we can even do it by e-mail. Many Cheers, Bob Carver
Q: Bob and friends, your design here appears well thought out and executed. May I ask, is your .15% THD at 180 watts output a midband measurement only? How do things hold together at your rated 23HZ and say 20KHZ where things usually get hairy? =:-o And in your experience, how audibly important are the ends of the humanly perceived spectrum? :>) JAY Dec-29-08
A: Hi '4298 Jay, This question is deep and complex, even deeper than you probably think; I love questions like this! Here goes. My (full power) 0.15% THD spec is at one kHz, whereas at 23 Hz it's just below 0.5%, and at 20 kHz it's about 0.35%. My THD analyzer has a 50 kHz measurement filter that helps my measured 20kHz number a bit. My transformer core begins to saturate at 707 volts rms (end-to-end) and 0.043 seconds. Nothing like those old vintage transformers! As far as frequency response goes, I like flat response to the ends, but power response at those ends is far less important, and in fact not important at all in the extreme. As an example of this, consider the RIAA curve, whose POWER response is down approximately -20 dB relative to 1kHz. This means the tweeter of a 200 watt system will never see more than about two watts! We can easily see this in our designs; a woofer voice coil weighs around a 1/4 lb (like a good hamburger), and a tweeter voice coil weighs about half a gram. Less than the tracking force of a cartridge on vinyl, and clearly unable to dissipate more than a few watts. This implies that full power from an amplifier at 20 kHz is not needed at all, and all who have seriously designed and listened to amps have come to realize this sooner or later. And of course the folks who designed our RIAA and vinyl system did so long ago. Still, power response is different from frequency response; since our human hearing mechanism normally extends from 23 Hz to 22kHz, and our threshold of feeling curve crosses the threshold of hearing curve at 23 Hz (in a normal human being of average physical dimensions capable of lifting big tube amps), we do need to go that low. Beyond that, 22 kHz is the normal upper limit for an eighteen year-old who has not been in a rock band. For the rest of us, we must have the music a few dB louder in order to get above our hearing threshold at 22 kHz. Thanks for asking a great question! Bob Carver
Q: Do you have any other amplifiers for sale? Thanks Dec-29-08
A: Hi Mark '98, I don't have any more tube amps that I built, but I DO have lots of vintage tube amps designed by the Masters of time long ago. I may put some up for auction in the near future; I wish I had some ready to go right now for you, but I do not. Keep in touch. bob.sunfire@gmail.com Thanks for writing, Bob Carver
Q: All I can say is "Holy-Wa"! Someday my fortunes will change..... Beautiful! Thanks for showing these! Rod KB8DNS Dec-28-08
A: Hi Rod 'DNS, I assume "Holy-Wa" is almost the same as HOLY MOLY ROLLERS! Like Captain Marvel (Billy Batson) used to say. Did you know DNS means "do not stuff" when appended to a schematic; it means the designer doesn't know if she or he wants the part installed or not. Happy new year! There is no doubt in my mind at all that your fortunes will change; they always do every day. Thanks for writing, Bob Carver
Q: Good Evening Bob, I Just wanted to tell you that I enjoy and am getting an education just reading the "Question and Answer" part of your e-bay auction, I enjoy it very much. The best of luck on this sale and I will say "Happy New Year" and prosperous 2009 Bob Carver. Best Regards, Jay Fletcher Dec-28-08
A: Hi Jay, Thanks for taking the time to write, for I've enjoyed being a teacher once again, and I'm glad you are enjoying the Q&A part as well. Thanks again for wishing the best of luck. Happy new year, best wishes and a great year! Bob Carver
Q: HI AGAIN YOU LOOK GREAT .THE MOST TRUSTED MAN ON EBAY. ...AGAIN THE BEST TO YOU ,HAPPY NEW YEAR FROM BRUCE AND CARLA FOREVERMUSIC414 BALTO MD Dec-28-08
A: Hi again 'music 414 Carla and Bruce, It's my big straw hat that makes me look good(?). Must be..... Happy New Year and all my best, Bob Carver
Q: Can you send it to Beijing? Thanks Kobemin Dec-28-08
A: Hi 'min, We do possess the technology to send it to Beijing. Actually it's not me, rather it's Boeing, Airbus, United Shipping, Far East landing Co. and many others including UPS or Fed Ex. Not to mention at least two governments. So the answer is yes, we can send it to Beijing. Bob Carver
Q: Can we get " Tubular Joe" to sign off too??? I have so much Carver stuff it's embarrassing!! Will you help me with set up if I win??? Thank you so much for your everything!!!! Dec-27-08
A: Hi 'king, You bet, all three of us! If you live close by, I'll come over to your home and help. If you are far away, I'll still help, but we'll do it by phone, e-mail and lots of talking. I sort of understand embarrassment, as I have too have lots of Citation amps, preamps and tuners. Best wishes and lots of luck, Bob Carver
Q: Does this work in 220v or do I need an adapter? If I need an adapter, would something like this work? http://www.110220volts.com/ATVR-1000.html Thanks a lot. Dec-25-08
A: Hi '871, This amp can be wired for 220 volts or you can use an adaptor,either way. The ATVR-1000 will work great;one unit will power both amps. Good question, thanks for asking. Bob Carver
Q: Hello Bob, Good to see you. I am still listening to your Phase linear Model 2000 series II, and Model 200 series II amp and preamp. Since parts are hard to get and they are 30 years old, any chance for you to come up with new circuit for their chassis to keep these fine vintage equipment going? Thanks, Joe Dec-25-08
A: Hi '123, No problem and no worries. Rita helm, the best fix-it true lady in all the land, has recently started a service shop to do just that. She has worked for me for over 20(!) years repairing and updating vintage Phase, Carver, and Sunfire equipment. She's famous! Send it to: Rita's Vintage Audio Service, 1920 Bickford Ave, Snohomish, WA 98290. Or call her at 425 530 9557 good luck and thanks for writing, Bob Carver.
Q: Hello Bob Carver, Mr. Carver I did not know at the time that I started writing to you that man you are a LEGEND and I am not "Blowing Smoke" </:-) Merry Christmas Bob!!! Jay Fletcher Dec-24-08
A: Thanks Jay, Merry Christmas to you as well! WOW! Your icon really does look like Santa. I'm going to try it. </:-) Oh well, for some reason my letters spaced themselves out too far. I tried. Pehaps the letters will space correctly when I push the "send" button. Cheers, Bob Carver
Q: I'm interested in learning more. I have built a state of the art sound room in NYC it's first class/ better than any dealers and I am moving this hobby towards becoming a business. I am currently a dealer for Wadia digital, ATC speakers, Analysis speakers, sme tone arms, ortofon products. I had a very bad experience with a Japanese solid state amp builder (technical brain). I've come running back to tubes. I've been into rolling tubes in other equipment I own and am stunned by the magic I'm hearing. I really liked the story behind your products and would like to explore more. Can you build a similar more powerful Amp? The sound room speakers the largest and best of speaker companies. Please advise... Bill Dec-24-08
A: Hi Bill '005, I for one cannot imagine a business more rewarding than audio. Lots of hard work of course and bumps along the way, just the same, NOTHING is more fun. There is no doubt in my mind but that your efforts will be super successful. And yes, I can build a similar and more powerful tube amp. An easy walk in the park, only problem is I would have to rob my museum to get all the vintage parts, or search the world for new ones, or make them myself (output transformers). If you have some pics, I'd love to see them. bob.sunfire@gmail.com Thanks writing, Bob Carver
Q: Hi there Bob - I saw your posting for the new amp - good to know you are still around and doing TUBES - in my collection I have 2 Citation I's and 2's - Do you contribute any forums, websites, discussion groups ? I would love to find out more about the DC fix you mention - Gary Boyd Dec-24-08
A: Hi Gary 'lues, I don't, but it's never too late, right? I had lunch with Stu Hegeman (the designer of the Citation equipment) around the time he came out with his HAPPY 1 preamp, and left that long and extended lunch meeting with many of his ideas and thoughts burned into my brain. What a genius he was! He showed me several important up-dates for Citation 2's, and I will be happy to share them with you if you contact me after the auction. That goes for my own DC restorer as well; I've put it into every Citation tube amp I own, along with Stu's up-dates. Anybody else want the information, just contact me as well after the auction. bob.sunfire@gmail.com Thanks for writing, Bob Carver
Q: My gosh, that's great! Keep up the good work. Hope you make plenty money and keep making amps. Best regards, Ray Harvey Dec-23-08
A: Hi Ray '1919, Thanks for the nice thought and for the enthusiastic cheer. I'll always make amps; couldn't stop even if I wanted to. As I've often said - Bob's my name and amps are my game. Hey Ray, you can be my friend forever! Bob Carver
Q: Hello, Bob. It has to have been close to 35 years since I attended one of your gatherings (in NYC, though for the life of me, I can't think where . . . Harvey, Lyric or Liberty, perhaps?) It is great to see what you've been up to and you have certainly piqued my curiosity. Is there a third amp available (the Citation has a center channel out, I believe)? And, as a side issue, can the ceramic input on the Citation be modified to a moving coil section? I had the I and II back in the day mated to Altec A-7s,then to some speakers of my own design. I always admired the Citations. The pre-amp was a particular favourite. Currently, these would drive EV TRX-15s in restored Karlson cabinets . . . if I decide to do it, of course. Everyone's business, including mine, is tapering off. Great to see your enthusiasm is still so strong! Dec-22-08
A: Hi '46 Bob, I can't remember either - probably Lyric with Mike Kay. Oh well, at least I do remember the gathering, and yes the ceramic input can be modified for MC. A walk in the park! And I've done it already. And it retains the Hegeman phono-stage magic. If you bid and win, and would like this update, no problem at all. Happy to do it. I have wonderful memories of working in Seattle Stereo Center where we carried TRX-15's, but not in Karlson cabinets. Hey, we are in the arena with no early out. One last thing, these are mono blocks, so an odd one (three)is easy. Thanks for writing, Bob Carver
Q: HI Bob, I'll throw in my two cents since I have first hand knowledge. Sorry I havent gotten back to you on the amp points we discussed but Ive been running different pre-amps and Speaker combo's hoping to settle on one and then get back to you but I gotta tell you, These things are like a Ritz Cracker, Everything tastes great on them. I ran one of your old C19's into it as well as a Marantz C45 and a really sweet and juicy like these nutz. Linn. Ive been looking for some tube pre's to audition and now you decide to offer a Citation also! Well, to let everyone know, all I can say is these are truly amazing and worth every penny I paid, and then some. I think I might stop by the repair shop next time Im in that neighborhood. Arent you in Cahoots with a repair shop there? However, I'll get back to you. Have a Great Holiday and Thanks Again!! Dec-21-08
A: Hi again '217, Good to hear from you, and glad you like the amp and think it's truly amazing! - you made my day! Really have. Ritz Cracker huh? I always thought more like a chocolate covered peanut butter cookie. You have a great holiday too, thanks for writing. Bob Carver
Q: Choosing Iron and Winding Transformers. Cont...? Dec-21-08
A: Hi 'blondies, Since these massive and expensive transformers were wound during the Golden Era for tube amplifiers, they were wound on the best core that money could buy at the time. However it was tough for designers of the time to get both low frequency core saturation and high frequency leakage inductance to vanishingly small values simultaneously, as these properties are almost mutually exclusive. Back then even the best transformer steel("iron")was not nearly as good as it is today, and in order to obtain the best performance, various artful winding methods were used to get it right. The way they did it was to wind many, many sections, interdigitated, interleaved and cross-wound while all the time insuring minimum leakage through the use of bifilar nesting of the wires inside the transformer. It became a true art form mastered only by a few. Today we can count all the great vintage output transformers on one hand alone. And they are and were EXPENSIVE! Today we have much better steel (though copper wire has not changed much),and different winding methods have evolved to take advantage of the new steel. A simple two or four interleave is the normal way it's done today. Dirt cheap by comparison. I think I loved my transformers more than my girlfriend when I was in college, and I don't know what I'm going to do when I run out. I have my old transformer winding machine; perhaps I'll just copy these using the vintage winding methods but with modern steel. I'm not out yet, if I can only find them. Fascinating question, thanks for asking.

This thread is meant to document the existence and sale of Bob Carver's New Silver Seven 900 Watt tube monoblock amplifiers which sold on 5/20/11 at 12:49am EST for a whopping $32,400. There was no last minute snipe bid.


Q: Hi Bob Simple question. Why dont you build a 300b type tube amp with lots of power? In my opinion and many audiophiles the 300b's sound the best compared to el34, kt88/ 6550. I suspect there will and always be debate on this but the KT120's are a new tube that manufacturers are not even using. basically its just a higher output tube and the same as a KT88. Im more concerned why not a 300b tube amp?, more power does not always sound better. May-19-11
A: Hi 'hadriump, That is a great question (I assume you mean an amplifier with a 300b single ended output stage). The answer is that I wanted to build the best amplifier of all time. If I thought for even one femtosecond that a powerful 300b type amplifier would sound better, I would build it. It's true when we say more power does not always make better sound, but in my long experience (I was old when Atlantis sank) more power almost always makes better sound if all else is equal, or if we only want to listen to wind-chimes at realistic levels. It just does! I have explored many, many amplifier topologies over my career, each exploration taking the form of a large series of converging experiments. The results of those experiments have taught me that a WELL DESIGNED push-pull output stage is the best sounding, and as a bonus, very practical as well as being quite energy efficient. Some history: Way back in the beginning of tube amplifiers,(in the 1930's) designers were forced to use class A single ended output stages in order to prevent a severe problem called "notch" distortion. Notch distortion resulted whenever a push-pull output stage was used. Push-pull amplifiers sounded terrible because of that nasty notch, exhibiting a harsh sound whenever the audio signal transitioned from positive to negative. As the years trolled by, many talented designers worked long hours to eliminate that notch (the reward would be huge). It took three men many long years of work to figure it out and get rid of the notch. One, a man named A.N. Williamson (of Williamson amplifier fame), and two others, Gordon Gow and Frank McIntosh. The last two guys started an amplifier company centered on the new technology. The problem was the output transformer, and these guys taught the world how to build output transformers that did not have a notch. And the high-fidelity industry took off. False beliefs often die hard, and the belief that somehow a single ended output ...Oops, I'm out of characters!
Q: I'm a fan dispite not having any of your equipment to speak of. (still hoping to be gifted a TFM-35,45,55 or 75... ok, dream ) I follow this forum and thought you would find this interesting or at the most, jump in the fray. Whoever wins these units will be blessed. Glad to see you are alive and well. http://www.audioasylum.c.../messages/16/165382.html May-18-11
A: Hi 'man, I am glad to be alive and well! Thank you for taking the time and for your audio passion. Bob Carver
Q: HELLO BOB, FIRST OF ALL I WOULD LIKE TO SAY THANK YOU FOR ALL YOU HAVE GIVEN TO THE AUDIO WORLD! YOU HAVE AN INTENSE AND LOYAL GROUP OF AUDIOPHILES THAT HAVE BEEN "BLESSED" WITH YOUR WISDOM AND INTELLIGENCE AND GREAT DESIGNS FOR ALL THESE YEARS. YOUR PICS SHOW YOU LOOKING HAPPY HEALTHY AND GRAND!!! KEEP UP THE GREAT WORK STAY HEALTHY AND GOD BLESS. MY BEST WISHES TO YOU AND YOUR FAMILY.............. May-18-11
A: Hi 'Huskys, Thank you - you have truly helped make my day. I hope I can continue doing the same for you forever. Best wishes and warmest regards, Bob Carver
Q: Dear Bob, I see it has 2 x RCA input on each monoblock / channel. Why 2? Are they balanced input (1 for + and the other for -)? Thanks! May-18-11
A: Hi '30 again, Nope, one is for direct (DC coupled) in, the other is an AC coupled input. The AC coupled input has as its low frequency cut-off 5 Hz. Hope this helps, Bob Carver
Q: Hi Bob long time fan here! How often do you put one of these out and do you always sell them on Ebay? May-18-11
A: Hi '3135, It seems about one per month on average. It's not many, but then they are built one at a time on a kitchen table by me and Tubular Joe. Good question, Bob Carver
Q: There is something puzzling me (among many), why are you selling them? If this amp is your magnum opus, why not keep them and enjoy the music for years to come? By definition, you can't have something better than these at home and if you sell them, you are settling for second best at home. I'm confused.... May-18-11
A: It all started when I was in the first grade with my 'Dick and Jane' reader. Dick was selling his toys on the sidewalk. He looked like he was having so much fun selling his toys, one of which was a small amplifier, that I became enamored with selling and still am to this day. While it's true these amps are, as you say, my "magnum opus," I can easily make another pair, so selling these is not a problem for me, but NOT putting them out there would deprive the lucky winner of a sonic experience they could never enjoy otherwise. The satisfaction for me in building amps like these ultimately rests in the knowledge that someone else will enjoy them as well. Hope this helps put together that puzzle. Warmest and best, Bob Carver
Q: Dear Bob, These are certainly amazing, but far beyond what my system requires. Any chance you will have either a pair of +/-200 wpc (rms @ 4ohm) tube monoblock amps (or a single stereo amp of same power) soon? Any chance of an integrated tube amp or tube preamp soon? I just need to drive some maggie 3.7's in a medium size living room. Thank you. May-18-11
A: Hi 'fin, Stay tuned for a 180 watt (clips at over 200 watts) cherry monoblock that I will be listing in the future. Someone once said "Good things are worth waiting for," but I don't remember who. As far as anything beyond that, I'm not saying. Thanks for joining my auction, Bob Carver
Q: I'm interested in this monoblock, however, do you offer 230V version? May-18-11
A: Hi '30, As I mentioned earlier, this amp has every de-lux feature known to man, woman, and all minor gods, so of course it has the feature of being 230 volt ready. All it takes is to select the primary voltage from several available on the split primary winding of the power transformer. An easy task for any technician who works on amplifiers. Or I can do it for your country's voltage if you wish. Hope this helps, Thanks for writing. Bob Carver
Q: Hi Bob. You stated that you "wanted a paint job even better than even the most powerful minor god could apply." It seems that EVERYTHING about this pair of amplifiers could be viewed in the same light. Just when I was beginning to think that amplifier designs, in general, had begun to go stale, you come up with these, blowing both me and my misconceptions away! You've mentioned the DC restorer, the output transformers, and certainly, the gargantuan output power these units produce. Are there any other engineering wonders lurking within the chassis that perhaps you've overlooked (not that they're required to make my ears already lust with desire!). I would love to own these, but frankly, they are too rich for my purse. But the sheer existence of units like these tells me that you are still a beacon of innovation in the world of 2 channel stereo and gives promise of still more to come. Keep it up, Bob! May-17-11
A: Profound silence..........more profound silence....Wow. It's true I wanted this amplifier to be remarkable. Here's what I did, at least at a conceptual level. I used dual KT120 power tubes for the output tube screen regulators, I designed it to be fully balanced from the output of the class A front-end stage with low voltage regulators and huge filter capacitors for enormous energy storage - way more than is absolutely needed. The power supply topology is a classic pie-filter with an inductor for absolutely perfect smoothing. I used the best high-frequency video pentodes that money can buy. The output stage is pure pentode using very high voltage and regulated screens. The regulator error amplifier is comprised of a dual 12BH7 which is capable of holding the screen voltage to within 0.05% of my target design voltage. Believe it or not, it's true! It took me so many tries to get the output transformer right I don't even want to think about it. I had sweat falling from my brow with the effort. The power transformer was easy, as big and as huge as it was, but the output transformer was so hard for me I wanted to give up, certainly when I found I could not make nature yield for me (for a great transformer). And now I'm glad I didn't. Then there is the DC restorer, a really cool circuit that allows some true magic to happen with the output stage. Of course it's not really magic , but we can think of it that way. More fun! I could go on and on, but you get the picture, nes 'pa? I don't want to put you to sleep, still, I may have already - please stay awake and bid! Bob Carver
Q: Hi Bob! Long time Carver/Sunfire owner here from NC! (C-2,C-1,M-400t,M1.0t's(2), A-760x,A-753x,A-200,TX-1-11 (2)Sunfire Sig. Stereo and Cinema Grand Sig. and the list goes on...)And I have a quick question about your (and indirectly, my Sunfires) Silver Seven 900w beauties. First and foremost: I love the sound of my Sunfires and I've always assumed that you voiced them from your original Silver Seven design. Would my SF's compare favorably within their power bandwidths in sound? Also (and most importantly) my Cinema Grand makes a "whirp" sound when the AC is cut from it and I've always thought this meant that there was a minimum of protection from the outputs to the speakers. Do these amps make a similar sound during power down and if so, does it mean anything other than the speakers are seeing the output straight from the taps with no protection gizmos. Thanks and sincerest best regards! Rick May-17-11
A: Hi 'chops, At the time of its (the Sunfire) design, I did not have a Silver Seven to directly compare it to, so I did it by memory. Later, when it was in production, I found my original pre-production version of the 'Seven, and guess what? I got it right even by memory. But I cheated - I also had a Mesa Baron tube amp that I DID use to help me along. The "whip" sound is nothing to worry about - just ignore it if it's not too loud. Has nothing to do with protection, rather it's a timing problem with the mute circuit not muting fast enough on power-down. It is totally benign and innocuous. As for these amps, tube amps designed with thermionic valves have no need for muting circuits, and no, they don't do it. Good questions. Thanks for writing, Bob Carver
Q: Bob, will these Amps drive my Original Quad ESL Speakers ? (Joke ! - they would MELT THEM DOWN !!!) Still, AWESOME AMPS !!! JimD, BAS ... May-16-11
A: Hi '1957, You bet they will drive your original Quads - right to the Pearly Gates after a total meltdown. Actually, with a voltage limiter installed (an easy task) they would give awesome sound. No doubt about it! And with safety too. Bob Carver
Q: Hi Bob, I contacted you a couple of months ago about a good friend of mine by the name of David Derda. He actually bought a pair of your original Silver Seven amps directly from you and has them to this day. His pair includes the stand as well. I shared with him that you had come out with a new version of the amp and he was quite intrigued. Im not sure if you ever contacted him or even remember him from way back when but Im sure he appreciate the opportunity to talk sometime as we was interested in your use of the KT tube. His number is 269.683.6332. Great looking amps by the way. I think youre a very interesting man and I could only dream to work under someone like you. I appreciate all the work youve done over the years for this industry. Regards, Lucas May-15-11
A: Hi Lucas, Wow! That was indeed a long, long, time ago. I wish I could remember, but I cannot. Thanks for the hi-five and for your thoughtful missive. Means a lot to me. After I get myself organized, I'll give David a call next week or so. It will be fun! Thanks again! Bob Carver
Q: I was wondering what the ac voltage and current for each mono block amp is. would I need to contact my power company for a nuclear reactor to run these,just kidding.Will they run on a standard 115vac 15 amp wall socket? May-15-11
A: Hi 'noo, Yes, they will operate just fine from a 15 amp wall socket. A 15 amp wall socket at 120 volts can deliver 1800 watts, and the amplifier draws less than that when operated at maximum output (just at clipping and full-tilt-boogie) using speech or music. Read on down through the Q&A's for a more complete discussion of this issue. I remember answering it several days ago, so I know it is here. Thanks for writing, great question, and an important one! Bob Carver
Q: Hi Bob: I've been a fan of your amplifier designs for almost 30 years and am glad to have a chance to communicate directly with you. Although the amp you have for sale on EBay is clearly beyond my means, I'd just thought I'd let you know that my first amp incorporating one of your designs was a Yamaha A-960 which I acquired in 1981. This amp stood up well for many years until I decided I needed more power and bought a used M 1.01. Compared to other amps I've owned, I was struck at how open and airy it sounded. This led me to my latest purchase - a Sunfire TGR-3, which I purchased a year ago, and which I absolutely love. Since it was being discontinued, I got a bit of break off the $5,000 msrp, although the price is by far the most I've ever spent on an audio component. Could I ask you a question? Is it better for the unit if I leave the Sunfire on constantly, rather than turn it off and then on again, when I want to use it? Thanks. May-15-11
A: Hi'gng, It almost does not matter weather you leave it on or turn it off. My Mother taught me to always turn electrical things off when not in use, and I have pretty much followed her advise. If you leave it on, you won't have to bother with turning it on when you are ready to make music. On the other hand, if you turn it off, you save the idle power which is about the same as a small light bulb. All in all, I say turn it off. Hope this helps - wish I could have been more emphatic. I cannot remember what I wrote about it all in the manual. If you have a manual, see what it says. If you don't, see if you can find one on-line from an after-market manual seller. Bob Carver
Q: Hi bob your amps are a sight to behold. a tru showpiece to all kinds of freinds. if youll allow me to be honest. how much better sounding are these behemoths better than your recently hand made and solid monoblock monsters. with power these are superior. vince May-14-11
A: Hi Vince, Thanks Man, I think they are a sight to behold too. We formed the chassis corners round, then followed with fine "wet or dry" sandpaper followed by lots of beautiful "Killer Paints" paint. As for the difference in sound between these amps and my Black Beauty amps, I'm not saying. They are both great, and like our children, each with a different personality, we love them both. We cannot say which is best. I don't think I answered your question though, but I truly did my best. Bob Carver
Q: Hi, Bob. What a captivating story. I had always wished I could own a set of Silver Sevens from its initial incarnation years ago. Alas, I am your average middle-class person who can only dream of owning something like this or the originals. It would be an absolute delight if you can design a delicious tube amp that someone like me can afford and treasure... May-14-11
A: Hi cice-joe', I'm glad you liked the history - it was FUN for me to remember it all and write it down. As for the delicious tube amp, someday. I'm working on it. Promise. Bob
Q: Bob, I have never listened to a tube type amp. I am currently listening to the original Fleetwood Mac(Peter Green) through a set of Maggie 1.7's driven by one of your Carver 760x amps. What would you say that I would gain. I know that is a very broad question, but they are both your amps so am hoping that you will take a shot at it. By the way , thank you for all the enjoyment that you have brought to our ears. May-13-11
A: Hi again '99, I can imagine that Fleetwood Mac, Maggies, and my amp would give lots of enjoyment - that's for certain. I'm a child of the 70's and Fleetwood Mac was a favorite of all my friends in undergraduate school. As for what you would gain, all I can do is try and describe an experience using mere words. It's hard to do, especially since I'm not a poet - I wish I were. But I'll try - here goes. The sound stage would be larger, with imaging (inside that soundstage) enveloping you with almost a magical acoustic. It will sound more delicious, more real, more realistic, more enchanting, you will be able to play it substantially louder but it won't seem louder, just more visceral, and will be able to give you even bigger goosebumps when you turn the lights out and allow yourself to float away. There is nothing, I mean nothing like a tube amp!
Q: Dear Mr. Carver, As I type, I am admiring the look of our vintage Silver Seven t amps, each sitting quietly at the base of KEF 107 speakers. A design detail (of many!) that allows these bespoke s.s. amps to feel special is the ghost-like "Carver Silver Seven t" (etc.) markings that only really become visible in close proximity. There is something very powerful and indeed tasteful about being understated. My point: I completely agree with your decision to keep things aesthetically "uncomplicated" with the stunning new Sevens. Your signature and nothing else should adorn them. Why clutter perfection! Ahwooga! Marc + Maria + beagles Vancouver Canuckland, BC PS Looking ahead, sure hope the economics support building more Silver Sevens if your busy schedule permits. I suspect that there is/will be considerable demand even if they end up selling for some crazy record amount. May-13-11
A: Hi guys, After more thought, I concur!
Q: Dear Bob, this is awesome, just the thing I need for cold winter nights... It reminds me of Philadelphia Experiment. If I buy it I promise to not treat the tubes in the same barbaric way... even if we cannot close the hyperspace door. So what is the bandwidth and the power consumption on these beauties? I would like to see the schematic also when you post it. Thank you! Cicel May-13-11
A: Hi Cicel, This amp actually runs cool as a cucumber. The tubes idle at only nine watts plate dissipation - we can touch them without getting burned. Though I have to say it would be uncomfortable, and it would not be wise to grab them for an extended time. Here are the most important specifications: Power into one, two, four, or eight ohms is 900 watts. power bandwidth extends from 18 Hz to 24 Hz. Frequency response is from 2 Hz to 100 kHz. The signal-to-noise ratio is minus (-) 120 dB A weighted, referred to 900 watts. Idle power = 882 watts, and the total input power at full output = 3120 watts. Here's the good news: a standard 15 ampere wall-outlet will work just fine because music or voice has maximum power requirements that are about five time more than the average requirements. This means that if we play the amplifier at full-tilt-boogie maximum, right up to the point where it would start to overload, the power from the wall outlet would be be about one fifth the maximum, plus half the total idle power. The grand total is approximately 1,153 divided by five, times two, plus 506 watts plus a fudge factor = 1,100 watts. A walk in the park! Hummm, bench testing would be a different matter though. Still, and just the same, even on the bench we would probably test one amp at a time. Hope I did not put you to sleep. If you're still awake, read on ..... Good question! Bob Carver
Q: Bob, if ever there was an amp worthy of your autograph, certainly it would be this one. No model name, no model number, just your signature,.....'nuff said. BTW, been a fan since 1984 when I bought my first piece of stereo equipment-the original Carver Receiver. I drove an hour and a half to the nearest dealer and fell in love with it the moment I saw it. Is it OK to say that in public? May you live long and prosper! May-13-11
A: Hi '6, "...live long and prosper", I like the sound of that! All is well and all is okay. I feel honored that you drove so far to get a Carver Receiver - I cannot help but wonder if it still works - does it? When I first started building these amps it felt funny not to have a name or a logo embossed on the escutcheon, and it took some effort to resist putting SOMETHING on. But I could not think of a cool name, so I gave up and let 'er rip with just a signature and a happy greeting. Thanks again Man, Bob Carver
Q: Doggone it Mr. Carver everytime we think you're tired of doing great things you do something beautiful. God Bless you. Peace. May-13-11
A: Hi again '1949, Thanks for you wonderful Hi-Five! Now I feel I'm floating on air. If you look closely as I walk, peering under my long black robe, you will see my feet are actually about three inches off the ground and I'm floating along. Very spooky, but fun. Thanks again, Bob Carver
Q: Hi Mr. Carver, I could never afford to own these or probably even rent the set for a week, however I do love vacuum tube audio. I currently use a restored Heathkit AA121 and a CJ PV-3. I work in Everett and would love to drop by and see / hear these masterpieces. Any chance? Thanks! Ethan May-13-11
A: Hi 'ii, Wow! You do live right around the corner. I do have lots of listening sessions with friends and colleagues - send me you e-mail address and you are invited. You will need to bring your AA121 and your CJ. Those are the rules. Best wishes, Bob Carver
Q: Hello Bob!!! Thanks again for signing my Sunfire Classic tube preamp.My question is will older Silver Sevens be able to be up graded into Silver Seven 900's? Thanks again you're MY hero!!!! May-13-11
A: Hi 44', What do you think - Bob's still my name and amps are still my game - of course they can be upgraded to a Silver Seven Nine Hundred. I have to warn you though, it's a big, big deal. New output transformers, two new power transformers, new KT120's, and somehow I would have to find a place to install five more output tubes. In other words, basically a whole new amplifier. That being said, it would be possible and practical to do it all, but refrain from installing the extra tubes (no room on the chassis really). With the additional circuit up-dated, with new tubes and transformers we would get about 750 watts per channel. Almost double the original 'Seven. The biggest problem I see is that it would sound funny - not the amplifier - but uttering its name: Silver Seven Seven Hundred Fifty. Ughh! However, perhaps we could reduce the power and call it the Silver Seven Seven Hundred - nope -too many "sevens". clearly it would need a new name. Silver Seven Hundred? I give up. The circuit's easy, the name's the hard part. See what you have done? Just kidding, warmest and best! Bob Carver
Q: Bi Bob! You seem so proud and passionate about these amplifiers and you obviously went all out to build them - I still can't believe the super paint job you decided to put on them, and if that's just the outside, I can only imagine what you put INSIDE of them! It clearly shows that they're your flagship amplifier! Just knowing that you designed the whole thing and that you actually build part of them with your own two hands, it's amazing! I wish I won the lottery to be able to bid on them, they're an instant classic, a collector's item, heck, they're more like an ultra-high-end-audio museum's main attraction!! I'm sure they will be the pride and joy of the lucky winner of this auction. I'm green with envy already! Since you're so passionate about these amps, I would think you really invest a lot of your time listening to them to make them sound perfect, what's the process you do to fine-tune and "voice" them? May-13-11
A: Hi seses, Thanks for your encouraging comments, and it's true I'm very passionate about my amplifiers - I hope you are right and that they indeed will become classics. That would be nice. As for the process associated with fine tuning - I'm not saying.
Q: Hey Bob. Boy these things are beautiful ! Do they happen to come with OO AWG a Stinger and Grounding Clamp ? LOL. On the serious side, would you consider these babies to be your Magnum Opus or do you have even greater plans for the future ? May-11-11
A: Hi '16dc, Well, these amps have been a lifetime in the making - I'm looking at the original super power tube amp I built while in college long, long ago. It's covered in dust and the paint (Red Burgundy) is chipped and marred - and it has not worked for years - I don't remember why not - probably because I could not stop working on it and wore the poor amp out. It sports vintage Tung-Sol 6550's. Only 12 of them, but what the heck, it was a start long ago. I honestly do not know what the future holds, so these ARE my Magnum Opus. At least for the here and now. As for the future, we will see. Thanks for joining my auction and for making me think, Bob Carver
Q: Are you will to provide the schematics so I could build these on my own? Also, if I was to build these on my own would you be willing to build the transformers I need for the amps? Thank you. May-11-11
A: Hi '318, I would be happy to provide the schematics. Later this week or next I will have updated ones posted on the Carver forum. As for the transformers, that is more difficult as it takes me forever to wind one. I'm soooo slow with a winder and I can't even stack 'em without making at least one error - I catch it of course or it would not work at all. Still, it is a long, long, labor of love to make a transformer. I'm thinking about teaching my laboratory assistant how to wind them, freeing my time up, or finally finding a commercial transformer house to make me some (for less than an arm and a leg). Stay tuned and please contact me later this year - I plan to have a solution for the transformers by then. I don't exactly know how right now, but I will by then. There's almost nothing more fun than building tube amps, so go for it with all the gusto you can find! Bob Carver
Q: hi bob this amp is incredible WOW! awesome keep upping the ante. I was wondering if you could make me an amp using 6973 tubes ..these tubes are very sweet and juicy like these nutz. .mostly find in old juke boxes .But im interested in more power as these only produce 12watts a piece .Looking to get monon blocks with these tubes but 50 - 100 watts a side .Your design seems to work can we do this with the 6973 tubes ..they are very impressive tubes and deserve to be used thank you bill.Ps its been noted that these tubes out perform the el 84 May-11-11
A: Hi '839, I guess I have been "upping the ante" so to speak. Oh well, I'll say it again - Bob's my name, and amps are my game. I can't help it! But honestly, I cannot think of ANY way to up the ante again after this almost unimaginable effort! 6973 tubes represent the last and the zenith of tube development in sensitivity and power response. They are remarkable tubes, and if you have some, they deserve to be used in a lovingly built amp. I don't have the time to build one for you, as fun a project it would be, but you are welcome to use my circuit and build one yourself. It would really work and sound wonderful. A ctually it would sound awesome! Happy building! Bob Carver
Q: Dear Mr. Carver: What a surprising and thrilling turn of events - we didn't see this one coming at all! You wonderful sneak! Well, we ADORE the new look of your all new Silver Seven masterpiece. Fingers, paws, and even wagging tails crossed that this auction is a big success. Kind regards, Marc + Maria + beagles Vancouver, BC CANADA, eh. May-11-11
A: Hi M&M, Bee too, what a treat to get your sweet and juicy like these nutz. missive. It made me smile. Warmest and all my best to all, Bob Carver
Q: Hi Bob, I have always been a fan of high powered tube amps.Im in the music business and use Marshall tube heads for guitar , I have always wanted to know why tubes always go bad or become weak after time, in your description of your silver seven you say the tubes should last 50 years, how come the other manufacturers cant make tubes in their amps last like that?Thanks for your time.. May-11-11
A: Hi '5201, Now THAT is a great question! I knew someone would ask that. Here's the deal - most musical instrument amplifiers put their output tubes through a lot more stress than an audio output amplifier. I am not a musician,still I have watched musicians play and they are HARD on amps, often using the amp as an extension of their musical instrument. Not only that but the amps idle at a large percentage of the tubes' rating. For example, I own a Mesa Boogie amp,and the 6L6 output tubes idle away at 24 watts each, representing an excellent compromise between longevity, musicality and distortion. The maximum rating on a 6L6 tube is 30 watts. So we see that the tube is idling at 24/30 = 80% of it's maximum allowable dissipation (heat stress). Now, longevity is proportional to the third power of the dissipation. If we compare that dissipation level to those in my amp, we find that the KT120 is rated for 50 watts dissipation, and I idle them at about 11 watts (thanks to the DC restorer), or only 22% of maximum. Finally, the ratio of 80 divided by 22 raised to third power is 48. That means (theoretically) the tubes in my amp will last 48 times longer than the Mesa Boogie tubes. Strictly speaking, for a variety of technical reasons the difference is not quite that severe, but you get the picture, nes 'pa? Great query! Thanks for asking, Bob Carver
Q: NICE, HOW ABOUT THE TRANSFORMERS? ARE YOU USING PIE-TYPE COIL WINDING? ANY SILVER WIRE IN THEM? THANKS! Ronald May-10-11
A: Hi Ron, Yes, this is a full transformer that I wound and received some wire burns from in the process. It's pie wound with six pie segments, and the secondaries are wound with pure silver wire. The primaries are wound with soft copper, oxygen free, and silver coated. I wanted to wind the primaries with solid silver as well, but found I could not handle the thin silver wire without breaking it, so I used the silver coated copper. That actually worked better anyway, for a variety of technical reasons - but that's for a different time. Thanks for writing, Bob Carver
Q: Is this a one off amp, or are they now being produced? May-10-11
A: Hi '99, Since Bob is my name, and amps are my game, I MUST continue macking these amps sometime, somehow. Problem is that there is only me and Tubular Joe building these one at a time. Therefore, sadly for the moment this must remain a one-of-a-kind amplifier. Still, and just the same, it's too beautiful to not build some more. We just cannot do it even in the near future. But someday! We spent way too much time on this amplifier not to have more of them peek their way into the sunshine and into our audiophile hearts and minds. So someday. Great question - thanks for asking, Bob Carver
Q: Hi Bob, Peter here again. Curious, have you ever auditioned your new amplifiers on your amazing ribbons? considering the inefficiencies, how would they perform?? I may want to consider such an amp, seeing that I never had any luck aquiring the original silver sevens. I should state that I am bi amping. Your saying that this amplifier is more than twice as powerful as the original...WOW!! Big fan of your products and designs. May-10-11
A: Ho 'O, I have indeed played my Amazings on these amps. Many times in the past and with my original Silver Sevens - more recently with these new amps, and I for one must say they sound stunning to me. And just for clarity, these amps ARE twice as powerful. Thanks for being my fan - you are helping make my day - and thanks for joining my auction. Bob Carver
Q: Bob -- Would that I had the gelt to buy these -- how beautiful and technologically interesting they are. Any chance you'll ever be putting out a schematice, if not for these then for a similar amp, so I can learn more about the DC Restorer? I'd like to better understand how this circuit works. Always learning... May-10-11
A: Hi xoons, I have put out a schematic several times, but now I have to update it so it's the latest, greatest. My plan is to put it on the Carver forum in the next week or so, so keep checking. I would do it now but I'm sooooo busy right now I just don't have time to sit down and draw a new one. I will in the next few weeks though. keep me posted. Thanks for writing, Bob Carver
Q: Hi Bob, is this actually you?? If so, would you mind giving me the oppotunity to contact you by email or phone regarding the platinum series IV?? I just sent you an email, but i"m not sure i sent it correctly. We met once at the LV CES show several years ago. I just need some info. Hope you can and are willing to help me thank you Peter....my email is creativedesigns@bellnet.ca May-10-11
A: Hi 'fast three again, Well, let's see if it is really me - I'll pinch myself hard, and if it hurts it must really be me. Here goes, ouuuuch, that hurt! Yep, it really is me! bob.sunfire@gmail.com I'll help and we will get your speakers working fine again. Bob Carver
Q: Hi Bob, Are we bidding on a PAIR of amps (Both channels) or is the bid price each? Also, will they work on a 240V/50Hz mains supply? May-10-11
A: Hi 'fast three, Oops, sorry about my poor clarity - we are bidding on a pair of SILVER SEVEN NINE HUNDREDS. A pair is required to make stereo. I just read my auction again and the only place I even remotely make it clear is at the top with the word "each". And even that is not particularly clarifying. Good catch 'fast three. As for 120/240 volt conversion, no sweat. If English idiom sounds goofy (or colloquial English is not your first language), the answer is YES. Bob Carver
Q: Mr Carver, First let me say that your contribution to appreciation of honest sound replication has made my life better!... oh yea! and beer. I own a pair of Seven's, had them about 20yrs now. I have never taken them apart to replace the tubes or for any other reason. having a basic knowledge of tube lifespan I'm aware that the tubes may need to be replaced... there is a slight hum in the system, I was wondering if the problem lies in the tubes, capacitors of possibly something else,is the balancing/biasing a critical part of making the amps honest and could I replace them myself? Even with the hum they sound great I'm a guitar builder and a musician, I've replaced a few tubes in my time and mechanical problems are only a solution away so I my question would be... what whould you reccomend? May-10-11
A: Hi Highnoon, This will be easy to fix - just call me and we can almost certainly fix it over the phone just by talking about it and performing a series of converging experiments that will lead us to a perfect fix. Call me at 425 487 4258 and we will fix it together. It is probably one of the 12BY7's. Does it do it on both channels? Does the hum go away when the volume control is turned down? Does the hum go away if a ground "buster" is used on the AC power-line cord? As an outside chance, though unlikely, it may turn out to be a filter capacitor, weak or stating to dry up. Not to worry, we will get it fixed! Of that there is no doubt. Bob Carver
Q: Hi Bob, Long time no talk. As I own a set of your Cherry 180's can you tell me how Sliver Sevens sound different, from the Cherry 180's. As we talked about at CF10, I changed the KT88's to to the TK120's for 260 wpc Hoping to see you in July I am planing a trip to Vancouver, will see you in Sept at CF11 Brian. Ottawa. Canada. May-10-11
A: Hi Brian, well, the KT120's sound the same as the KT88's provided the bias current is adjusted to be the same. They will sound different if the bias voltage is set the same. Usually if we simply change the tubes without doing anything else, the amp will sound more forward with a tighter focus with the KT120's, and will posses a larger acoustic in a big acoustic space with the KT88's or KT100's. Hope this helps, Brian, oops, I mean Bob Carver
Q: Jumpin' Jehoshaphat, Bob! These babies are a sight to behold!! Looking at the pictures and reading your description, however, cause me to wonder about a couple of minor details. First, you state, "Four output terminals; common ground, one, two, four, eight and sixteen ohms," which seems to me that it is six (6) rather than four output terminals. Am I missing something? Second, these are monoblock amplifiers, yet I see a pair of RCA coaxial connectors on each. Is this supposed to be some kind of variation on a balanced input, using isolated coaxial connectors, or is it something else? Let me also just say that these babies are absolutely bee-you-tee-full! If I had these killers at my place, I wouldn't need any form of external heat source as I'd have these mothers hot and rockin' all the time! Keep these great amps of your a-comin'!!! -joe May-10-11
A: Hi 'amd, If you think they are a sight to behold in the pictures, you should see them in real life - the finish is five miles deep and sparkles like diamonds. As for the output terminals, each one does double duty. The power band is so wide that it almost doesn't matter which tap we use to drive a given speaker because the amp can deliver its rated power, for example, into four or eight ohms on the same output transformer tap. This means that the power into an eight ohm resistor will be the same regardless of whether it's hooked to the four or eight ohm tap. Consequently, the taps are, in order, one to two ohms, two to four ohms, four to eight ohms or sixteen ohms. Now my head is spinning. The RCA input jacks accept either a DC "lab direct" signal or an AC "normal" (capacitor coupled) signal just to be on the safe side when a real-world preamp is used. Good eyes Captain! Bob Carver
Q: Wow!! $5,000 dollars just for the paint on this amplifiers? May-10-11
A: Hi'ses, I know, I know! Here's what happened - I knew I wanted a paint job even better than even the most powerful minor god could apply, so I went over to "Killer Paints", looked around their shop, and saw a beautiful motorcycle. I pointed my trigger finger and said' "I want my color just like that!" It reminded me of my first car. I said "Give me the best paint job you have." I new it would be expensive, but not just HOW expensive, and I did not ask how much it would cost. Was I in for a surprise! It took about five weeks, and from time-to-time I would go to the paint shop and view the progress. I gotta say it was gorgeous! Try 18 layers of hand rubbed cellulose acetate nitrate lacquer, followed by six coats of clear-coat, each hand polished between coats. Each chassis took many days to finalize. I was to the point of being afraid to ask how much, and really was starting to get nervous. I kept my silence and when I picked up the chassisum (plural of chassis?)I was amazed and overjoyed! I knew I was in the presence of greatness! Also sticker shock. In the end, I was happy. The pictures here do not do justice to the real, live paint finish. The real amps looks way more stunning than my pictures do - don't know why exactly - they just do. Bob Carver
Q: Hey Bob... The new amps are stunning, and the point-to-point work is nothing short of stellar. These look to have more tubes in them than the original Silver 7's did. It would appear that these have more in common with the incredibly rare Silver 9's (two or three pairs I believe)... Do you have plans on building more of these amps, as you have done with the "Cherry" series, or will these be a one time deal here on Ebay? I would love to have these, but with a move coming up, the finances are not there at the moment. May-10-11
A: Hi John, What sharp eyes you have! These new amps DO have more tubes than the original 'Sevens. And, and otherwise they are substantially different (from the '9's) - about double the power - plus they have a current feedback loop that the originals did not have, allowing them to "listen" to the room more and generate a bigger acoustic space, my DC restorer which allows the output tubes to run cool, deliver lots of power with lower distortion (not that it needed lower distortion), as well as my latest thinking regarding power amp design. As far as building more, it will be a long, long, time. The paint itself was done by "Killer Paints", a shop specializing in exotic motorcycle and car painting;the paint alone for the four chassis cost $5,000! I went nuts. Not only that, but Tubular Joe labored over these amplifiers like like non other and the effort truly exhausted him. Oh well, the future lies ahead - we'll see. Beyond that, I cannot say, so I'm not saying. Hope this helps, Bob Carver
Q: Bob, You gotta stop listing all these beautiful amps. Everytime you list one it takes me hours to clean up the drool. That is sweet and juicy like these nutz.!!!!! May-10-11
A: Hi'6501, No way, Bob's my name, amps are my game. Bob Carver

Found this posted by Bob over on another forum; never seen it before~

FYI regarding "adamantine steel"directly from Bob Carver's mouth:



The first time I ever heard the expression Adamantine steel was as a young child when I watched the classic science fiction movie, “Forbidden Planet”, the screen adaptation of William Shakespeare’s “The Tempest”. William Shakespeare loved Adamantine steel. It appeared in several of his plays, most notably “A Midsummer Night’s Dream” in which a sword of Adamantine steel was crafted. In recent times my use of the expression Adamantine steel derived not from the Fantastic Four comic book, rather the Conan comic book in which the minor wizard Xolotan (sp?) crafted a beautiful sword of Adamantine steel. The most enduring image I have of Adamantine steel is when the Krell monster from the Id of “Forbidden Planet” broke through an impenetrable steel door crafted of Adamantine steel. It seems that more than one audiophile has used the Krell of Shakespeare’s forbidden planet to define something regarding amplifiers.

In truth, Adamantine steel is an actual steel developed early in our century (I think in the 1930’s or 1940’s) to define the hardest steel known to man. And it still is. At least as early as 1952, U.S. Steel had a catalog including Adamantine steel with a hardness rating at the top of the list of all the steels it produced.

I chose the Krell Adamantine steel for my output transformers because to this day it is the hardest steel known to humankind. And the harder the steel, the lower the induced eddy currents and the better the transformer.

As for designing this amplifier without true science, using only the language of audiophiles severely misses the mark. It’s not possible to design an amplifier at this level of performance without extensive use of physics, science, and mathematics. To believe otherwise exposes one’s own knowledge to be of a meager and shallow kind.

A final word. Since I invented these output transformers, I get to call them anything I want.

Bob Carver

Funny. Forbidden Planet stuff. The Krell and all. It's kind of a made up word like unobtanium, adamantane is.

That's one of the reasons I love Bob. He tells it like it is.

Funny. Forbidden Planet stuff. The Krell and all. It's kind of a made up word like unobtanium, adamantane is.

Not really made up just not used like it used to be anymore. The word Adamantine has been used throughout ancient history and refers to anything that was made of a very hard material.

In the Forbidden Planet Movie Moribus refers to structures that the Krell Civilization created that were made of Adamantine Steel (referring more to the strength of the unyielding Krell Metal rather then the actual name)

I thought Stellite was the hardest known steel??? Maybe Adamantine is the hardest known "magnetic" steel...

Bob has had several auctions since last post:


Bob auctioned another pair of the KT120 driven 305 watt monoblocks which sold for $7500 on 10/16/11.

Q: so the idling voltage for this unit is:-??? Oct-10-11
A: Hi 'sies once again. I think you mean idling current. It can range between 0.010 amperes per tube (7.25 watts) to a high of 0.062 amperes per tube (45 watts), depending on the setting of the bias pot and the sound you like. Good question, Bob Carver
Q: Hi Bob I have had the great pleasure of owning your TFM-35 since the early 90s and have just bought an upgraded M1.0t carver amp that was upgraded to the mk2. Have you listen to any of them and if so what do you think of them Thanks and god bless you for all you have done for music lovers like me. Oct-10-11
A: Hi 'slam, You are making my day - I enjoy hearing about my vintage designs still mustering on after so many years - actually not so many in the great scheme of things. As for listening to them, of course I have. So much so that I am blue in the face sometimes. As for what I think of them, they are great amps able to deliver gobs of current at ridiculously high voltages. Very similar to a tube amp at that. Thank you 'slam for tatking the time to write in. Warmest and best, Bob Carver
Q: Dear Mr. Carver... I think the above message title says it all. I am not eloquent enough to say much more than that... If I won the lottery... or decide to rob a bank before the auction is over... They will be MINE! Best Regards, Onchu Oct-10-11
A: Hi 'hu, I gotta say, you are making my day! Thank you a lot. Bob Carver
Q: hi bob: does this beauty can be singing with kt88? Oct-10-11
A: Hi, Man, The answer is absolutely yes! Bob Carver
Q: hi bob: as my shallow experience! plate current really affect the sound in overall, for kt 88 my own taste is about 450v max at idle otherwise the sound would be too tense. for this amplifer with kt120 output tubes what is the factory setting of the plate current at idle? Oct-10-11
A: Hi 'sies, Ahh, simple question, complex answer. Here's the deal: In general, the idle (Quiescent)current in a tube amp substantially effects the sound. Most tube amps idle the tubes on the hot (max) side to give the best sound, and usually the designer says what's best. So we see that we have an optimum idle current define by the designer of the amp AND the manufacture of the output tubes. Too much and the tubes are in danger of run-away, and too little they will not give the best sound. The box is small and designers find themselves boxed in. So a compromise, as in all human endeavors, is called for. In this (my) design, the box is large, there is no optimum idle current, rather there is a RANGE of idle currents, all of which are "in the green", and safe. This is due to the DC restorer circuit, as well as the current feedback loop which allows the amplifier to "listen to the room", as it were. This happens via the loudspeakers acting as microphones and feeding that signal back to the input of the amplifier by way of the current feedback loop. The final result is that the tubes idle cool, will last 50 years (unless a catastrophic failure occurs),the sound can be tailored from a huge beautiful soundstage to an up front presentation, and in general will give a big, sumptuous soundstage with pin-point imaging within. Hope I have not put you to sleep with my long answer - If I have not, then read on. Bob Carver
Q: Hello Mr Carver, you build beautiful things. I got my first Carver amplifier when I was about 15 I believe. I still own your 1090 integrated amp, I fire it up from time to time I love it's control and power. For some time now I've been wanting your opinion on two things. The first is: Do you believe that XLR pre-amp to amp connections offer a better signal transmission to the point that one should go out of their way to match components so that they have that option? My other question is this: In your opinion is upgrading an amplifier or any other audio component's power cord really going to create a noticeable audible difference?? I guess in some ways I feel like many of these "upgrades" are sort of the audio worlds snake oil. I ask this of you because I'v only seen balanced inputs and detachable cables on your Light Star amp, one of which I am currently bidding on. If you have a chance I'd love your opinion. Thank you for all that you have given us, Zachary Kelley Oct-09-11
A: Hi Zachary, I get great sound from vintage RCA input jacks as well as the newer ones that have a longer ground connection. Balanced inputs make sense if there is a lot of hum or noise in the environment, as the minus signal gets canceled by the + signal. But if there is no hum to begin with, it makes not one bit of difference. Not a whit! A good home installation should NEVER have hum, no matter what! Balanced were designed to cope with hum and noise on very long cable runs as in outdoor concerts and other industrial applications. Read on - my other comments on line cords. I think these amps are beautiful amps too, if I may say so myself. Anyway, thanks for writing in, you have made my day. Bob Carver
Q: Hi Bob, My question is not about your fantastic tubed amps here. It has to do (and i respect your answer over almost all others... and thats's no smoke) with whether older pieces of gear, yours included, need to have things like caps and other parts that dont show any damage (and the component is working correctly as heard by ear) changed for new ones? do caps and other stuff go "bad" and need replacing even if the piece still sounds good without any obvious noise abnormalities? thanks for your time, Bob, and best regards! Tony. Oct-09-11
A: Hi Tony, Let's say an amp blows up, comes in the shop for repair, and I find a blown cap in one leg of the power supply. I would then replace both legs just to make sure. I would not replace all the other caps unless they were leaky or bad. My thinking is that if they have lasted 25 years without a problem, they will be good for another 25 years, perhaps even 50! That's the way it works because the capacitors have all survived way past their infantile failure time- period. Hope this helps, excellent question - glad you asked. Thanks Man! Bob Carver
Q: Thanks Bob for making the issue clear on electrostatics. On a more mundane note, I see you favor a captive power cord; can you add an IEC for third party PC's - I bet you have a view on that! Steve Oct-09-11
A: Hi Steve, also 'bs, the previous guy, Yes I can add an IEC cord, but I think a captive cord is better - no contact resistance. I also know that my captive cord makes it more difficult to upgrade the power cord. I cannot add one to this amp because it's already built, and I think it sounds just the way I wanted it to with the HUGE power cord I designed into it. Honest! I remember writing about this issue somewhere in the "Ghost Questions From the Past", but I'm not sure. They are at the bottom of the description. I will convert the amp for 240 volt operation if you wish. The transformer has a split winding so it's easy to change back and forth. Any service guy can easily perform the conversion - takes perhaps 15 minutes per amp. Thanks for writing in again, Bid away! Bob Carver
Q: Hi Bob, I have just purchased some B&W 802D speakers and am interested in your opinion on the match using your monoblocks to drive these speakers. Also as I now reside in the UK for the next couple of years, but will eventually return to Canada, how easy is it to modify the power supplies? Would you be willing to prepare step by step procedure c/w digital photos covering this scope? Also please provide the dimensions and weight for each monoblock amp. Thanks Oct-09-11
A: Hi 'bs, oops, that sounds funny, Back to being serious - I used a pair of B&W 801 speakers that were designed long ago and used them extensively in the development of these amplifiers. Your B&W pair have very similar characteristics throughout the main audio spectrum, and even though I have not had 802's, I know that they would match these monoblocks beautifully. That's because B&W has long built their speakers with more back-electromotive force in the drivers than almost anybody. This is evidenced by simply looking at the drivers - they all have huge magnets! These large magnets, and the attendant back-emf drives the special current feedback loop in these amps such that the system can listen to the room substantially better than most. This helps yield a big, beautiful soundstage with great imaging inside that large acoustic. It did on the 801's anyway, and there is no doubt that the same results would be for the 802's. No doubt at all. My 801's sounded stunning with all 12 output tubes delivering high power and and all that current. Warmest and best, Bob Carver
Q: Hi Bob, I have both Scintillas and Martin Logan CLX's. Can you comment on the ability of the amps to drive the difficult electrostatic loads as conventional wisdom has it that tube amps cannot maintain a grip on the bottom end or deal with the roll off at the highs? Thanks, Steve Oct-07-11
A: Hi Steve, It is an old wives tale and a false belief that tube amps have trouble driving electrostatic loud speakers. A powerful, well designed vacuum tube amplifier actually yields great sound with an electrostat. The impedance curve has a rising response in the low frequencies, typically a dip in the upper midrange, and a tube amp in principle can follow these variations unlike a solid state amplifier yielding a beautiful base line and a sumptuous midrange. This is evidenced by most journalists and reviewers loving the sound of an electrostatic speaker mated with a valve amplifier. Great question. Thanks for writing. Bob Carver
Q: Bob, This probably isn't the right forum, but you said bring on the questions. I recently purchased one of your early 90's C19 reference preamps and it's pretty impressive. My only issue is with the sliding gain switch. Are they always so noisy when switching through the gain positions? I've deoxed it and cleaned it manually but it becomes noisy after another day or so. Any suggestions (other than buying a new board)? Thanks. Oct-07-11
A: Hi 'd, No big deal; an easy fix. The coupling cap that goes to the switch has become leaky. Perhaps even the one that leaves the switch. The switch itself was a nice, hi-quality unit, still, it IS 25 years old or so! No need to replace the board, just get a schematic (available on line)and replace the pair of capacitors. As a good measure, you can also replace the switch if cleaning it one last time does not do the job. Spay de-oxit, then move the switch back and forth one hundred - yes 100 times, to remove the noise. Your arm will get very tired, so it will help to have a friend share the back and forth switching. Spray fresh de-oxit on after the first 50 switchings. Actually the capacitors may be okay. Try the 100 times first, and see if that fixes it without the new caps. That way you won't have to find a schematic. This will fix it, Hope I have helped, Bob Carver
Q: Hello Bob. Wow those are so nice man. I would love to own such beautiful working art. I have owned many pieces of your work over the years and have managed to hold onto a few solid state pieces. Yep I still have a Phase Linear 700B, 700 series II and a beautiful c-4000 preamp which I bought all brand new. So here's a question for ya Bob. What do you think of your old ss monsters? And I would like to here more about you museum. cheers, Mike Oct-07-11
A: Hi Mike, Well, I poured my heart and soul into those amps - my favorites are the TFM series and the early magnetic field amps. I thought they sounded great, and I still do. While I'm thinking about it, an important difference is they are not tube amps; consequently they cannot listen to the room (See the above questions and my answer on this topic). It's facinating to think about. As for my museum, I am afraid my basic character flaw has arisen - procrastination. I have rounded up all the items I want for it, but have not yet begun setting things up. I have the place, the stuff, the history. Your question will definitely go a long way in getting me off my tooosh to get going. Thanks for joining my auction, Bob Carver
Q: Hi Bob .. I'm a long time fan of yours. Love your gear and what you've done for the audio community. Here's something that might interest you (it may seem a bit whacko at first .. stick with it and understand the concepts, they may be of use to you in transformer design): http://www.youtube.com/watch?v=40xq_sJfyWY Regards Oct-07-11
A: Hi '101, Thanks for the tip, I'll tell you - I really like reading about tube amps and output transformers. I'll be visiting the site this weekend and will get back to you regarding what I find. I'll answer by tagging my report onto one of the questions that will be asked, even though the specific question may not anything to do with output transformers. Thanks Man, Bob Carver
Q: Is this auction for both of the monoblock amplifiers please? Just wanted to be clear.....these are amazing! Thank You! Rob Oct-13-11
A: Hi Rob, Good catch! Yep, this is for TWO Monoblock amps. I should have been more clear - next time. If this auction were for only one amplifier, you would be forced to listen to only one speaker, sort of like one hand clapping. Hope this helps and makes things clear. Bob Carver
Q: Hi Bob, I hate to encroach on your valuable time but, I was hoping you could help shed a ray of hope in restoring my Amazing Silvers. I absolutely love these speakers and in the process of refinishing the cabinets, I cut the wires too short from one of the circuit board attached to teh bottom of the ribbon panel and made a mess of the board attempting to resoldier the wires. I have somehow managed to get the replacement boards but, I have no idea how to mount the new circuit board w/o damaging or disassembling the ribbon panel. I have tried to get help from numerous forums but, no one seems to be able to help. I am heart broken as no speakers I've heard even those in the tens of thousands of dollars range (proacs,wilsons, ruarks,thiels,etc)came close to the sound I was able to achieve in my basement with it properly set up. I was wondering if you can offer me some advise or help direct me to someone who can. If not, I just wanted to commend you on your awesome designs over the years Oct-13-11
A: Hi '2012, I know exactly what is wrong with your speaker. It's only the terminal strip circuit board and it is very easy to fix. Not to worry, we will get it fixed together over the phone. Send me your e-mail and phone number to bob dot sunfire at gmail dot com and I'll call you back. You will need to have the speaker away from the wall so you can easily get behind it, a nice bright flashlight, a soldering iron and some rosen core solder. Also a friend who has had soldering experience (if possible) and someone to hold the bright flashlight as well as a small piece of fine sandpaper amd some Vaseline petroleum jelly. If you don't have a friend who can solder, that's okay because we (you and I) will practice over the phone until you can solder a great joint! Then we will proceed on fixing the speaker itself. Not to worry. Bob Carver
Q: Hey man,,, I always wanted a set of tube amps, why not start with the best? That being said; Are you going to produce more of these or are these a 1 time offering? Are these 1 of 1 or 1 of ??? On a technical note; Which speakers do you believe would be best suited to these amps? Which pre amp? I believe the adage, "Garbage in, Garbage out" no matter how great these amps are, if you feed them crap, that's what you'll hear. I am not ashamed to say I don't know and also not above asking the "Creator" for his recommendation. If you don't know, who would? Last and truly not least; It is truly a blessing to see a man enjoying his craft and having a willingness to share it with the rest of us, Thanks Man! I truly hope the one who ends up with these truly appreciates the soul that created them. Oct-13-11
A: Hi Triple zzz, Yep, these are the best! No doubt about it, if I may say so myself. As I have often said, I could not stop building amplifiers even if I wanted too. No doubt a voice would semi-awaken me in the middle of the night and I would build one while sleep walking. Tubular Joe and I are building about one every month, a far cry from my earlier Carver days where I built about 5,000 amps, pre-amps and speakers per month. In the vintage world, go for a Citation I, my own Sunfire tube pre-amp, or a Marantz seven. I love Apogees, DQ-10's, Quads, Amazings, IRS Betas, Soundlabs, the list goes on and on. So many great vintage speakers, and they are an incredible bargain when compared to most contemporary speakers. I gotta say, thanks for your enthusiasm in what is arguably the most fun hobby of all time. Warmest regards and best wishes, Bob Carver
Q: I read every word and then re-read all your comments again. Nice color selection. Some uninformed folks have discounted your designs over the years, but I own a Phase Linear 400 and a bunch of Altec 9444's and a 9446 and a stack of 604's. They all sound great, but I always wanted one of your tube amp setups. I love the low eddy currents in the hard steel cores, that's why you do it. Nice, and so few understand this and the low impedance coupling and back emf. I upgraded one of your C-1 pre-amps for my brother with NE5532 op amps, hope you aren't offended, they have that Neve sound now. They sound really great to him and he won't ever sell them. I like that there are only 2 op amps in each audio path, very nice design, I rebuilt the rotary switch. I fly RC planes and was so excited to find out you did too. Too bad I missed that whole era where you gave away gear. You would have a blast on Zagi combat night. Thank Tim too as I am in awe of these 300 watt gorgeous monsters. Oct-13-11
A: Hi '01, I cannot tell you how much fun, and how satisfying it is for me to hear about your passion for audio and all the experiments you clearly have done over the years. There are few endeavors more interesting and challenging (and just pure fun) than restoring something that did not work and bringing it back to greatness. Whenever I get that chance, I take it to bed with me that night and place it on the foot of the bed. Then just stare at it until I fall asleep. Thanks for taking the time to write as well as your passionate thoughts. Warmest regards and best wishes, Bob Carver
Q: Hi Bob, I have a lot of gear. Even had you Silver Sevens that I purchashed from Lyric back in the day. Still regret selling them. Anyway, would you be interested in exchanging the amps at the closing cost for some equiopemt that you might have an interest in? BTW, I, too am using Apogee Full Range sopeakers with four VTL Wotan amps. I have tuners, reel to reel tape recorders, new, sealed collectible LP's, never played "The Tape Project's" 20 RTR tapes, etc. I promised my wife who has been great over the past 20 years that I wouldn't allow any more gear into the house (I do cheat , but it's on a rare occasion)but your amps are simply stunning. For example, if the bid ends at $10,000. then I would give you $10,000. in credit to pick what you want from my collection (except for the Apogee's). Please let me know what you think. Regards from a long time fan and owner of Phase Linear/Carver/Sunfire (currently 2 amps and 3 preamps). Regards from Bob Cicarell (Same initials!) Oct-13-11
A: Hi BC, You carry a good name - just ask me. Silver Sevens from Lyric - those were the days! I said in this auction that I accept any form of rational payment, and I'm serious about that. So count me in! I would indeed be interested in your idea, even though the Apogees are not included. Bid away my new friend! Bob Carver
Q: Dear Bob, Warm & fuzzy greetings from our igloo in the Great White North, eh. Any developments with the passport? A bit selfishly admittedly, we really look forward to pampering you with a deluxe BBQ (featuring what may be the best potato salad in the Milky Way Galaxy) or maybe even our top secret "Kung Fu" pot roast. Some audio news, we purchased KEF-BBC LS3/5a studio monitors for the Baby Seven Black Beauty; unfortunately, we have yet to experience a bar or even a note. The problem could be the external LS3/5a crossovers but, as documented previously, the amp sustained significant damage during shipment. (Fyi, I have tried powering other speakers with the Baby Seven but to no avail.) Conclusion: Your tube-y expertise is needed! Best, Marc + Maria + hounds Vancouver, BC Email: fuzzymoose@telus.net P.S. Another possibility when schedules permit… We would love to drive down to Snohomish some weekend. Oct-12-11
A: Hi Fuzzy ones, oh second family, LS/35a's are grrrreatt speakers, and just the ticket for some superb listening with a Baby Black Beauty. Have I got a deal for you! I just finished a REAL Baby Black beauty and it has your name on it. It is part of my lifetime warranty -the least I can do. I just got back from Disneyland with my daughter and as soon as I finish tuning it up I'll send it to you or hand deliver it - my preference. Sorry about the freight damage that has apparently broken it. The new one is much more handsome anyway. You can see some pictures on the Carver forum. You have probably already seen one though. I don't have my passport yet, but will soon. Stand by, Bob
Q: hi bob: great idea to have dc restorer! the plate voltage in normal kt88 or kt 120 pp amp is about 420v to 500v/? can u descride in terms of plate voltage in your amp? Oct-12-11
A: Hi 'ies, The plate voltage on normal amps is about 450 volts as you describe, but this amplifier is anything but normal. The plate voltage rating for the Tung-Sol KT120 is 850 volts with a signal power output of 150 watts rms per pair of tubes! This Black Beauty operates with a plate voltage of approximately 700 volts, thereby producing 305 watts total, or about 102 watts rms per pair of tubes. That's 305 watts in all. That is how it does it - very conservative. Bob Carver
Q: hello, two questions ... ok three 1). how is over tempature prevented on your amp. I understand that overtempature can cause meltdown... or distortion increase.. 2) line filter( power spikes) how does your design cope with poor electricity from the local utility... 3) can the amp be used on 50 hz current?? I live in Europe and the voltage is 220 vac, you have not said what percent the total harmonic distortion is. thanks turps. Oct-11-11
A: Hi '88, I love questions like these, I don't know why, I just do. The main way the temperature is kept to a low and safe value is by designing the amp to intrinsically run cool. For example, each output tube idles at about nine watts, compared to most amps which idle the output tubes at about thirty or more watts. The glass envelope of the KT120 is huge and the tube is rated to dissipate 150 watts. That means this amp is operating at one tenth the normal dissipation. It runs cool enough that we can easily touch the tubes without getting burned (though it's uncomfortable and I would not do it on purpose - don't tempt fate), thanks to the DC restorer circuit. Additionally, the warm tubes act as an air pump and pump cooling air from underneath the chassis up and out the vents on top, further removing operating heat. This amplifier runs COOL! Line power spikes are handled by total over-kill in the power supply filter section, using six, yes SIX 390 uf capacitors! Energy storage that would be the envy of any vintage designer! Not only that, but the screen circuits as well as the front-end 12AX7 tubes have their own dedicated supply. In addition, the power supply common mode rejection is about 120 dB even before all that. This is due to the long-tail differential pair at the input, and the circuit remains fully balanced all the way to the output transformer. It is virtually impervious to line spikes, with all but the biggest lighting strike not ruffling the output at all. I'm exagerating here a bit for fun, but you get the picture. The power transformer has been designed such that 240/50 Hz or 120/60 Hz is good. The magnetizing inductance of this transformer is about 20% greater than normal, even for 50 Hz. THD = 0.50% at full output, and diminishes at lower levels. This is the classic distortion profile of vintage tube amps. Oops, out of characters, Bob Carver

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$6850 on 11/10/11 is the price of the latest pair of Bob's creations, KT120 driven "Cherry Berry" 305 watt amps. Short Q&A.

Question & Answer Answered On
Q: THE 6AL5 TWIN ISO DIODE TUBE HAS BEEN USED IN MANY CIRCUIT,S OVER TIME. IN TUBE HISTORY,MOSTLY IN TV TUBE CIRCUITS.PRETTY SHARP ON YOUR PART TO USE THIS THIS TUBE AS A ZERO CROSSING DETECTOR TO SHUNT ANY GROUND OSCILLATIONS FROM THE PRIMARY TRANSFORMER KICK BACK.CUDO TO YOU BOB. Nov-09-11
A: Hi 'noo, Glad you noticed, I first got the idea a long time ago while working at Pierce Arrow TV in Los Angeles. I was in high school and part of my job was to put the Sams' Photofact schematics back on the shelf. I read them all and noticed that hi-end video amps driving the picture tube had D.C. restorers consisting of .. you guessed it .. a 6AL5 vacuum tube. I was building my first little tube amps back then and thought what a great idea it would be to put one in the circuit of my 6AQ5 output tube and make it last forever. That was unnecessary because they lasted a lifetime just the way they were (my lifetime, I was only 15). The big surprise came when I discovered that the distortion went way down as well as the operating temperature. I don't know why it was not thought of before, it's been starring us in the face all these years, and the TV guys have been doing it all along for video. I guess the video guys just thought an audio amp was a video amp that was slow and never bothered to share their design with us. Ha! What did they know? An audio amplifier is non-trivial, and harder to get right than any video amp. But I ramble, Bob Carver
Q: Edit: For those who are a little gun shy about the sound of these amps…I have a pair connected to a pair of Infinity IRS Betas and I think they are THE most outstanding sounding amps around. The bias adjustment Bob has implemented is to die for (because of the DC restorer mainly) and you can dial in the amount of Tubeyness you like with the bias control. I have my bias knob dialed all the way down and get the full tubeyest of tube sound. Granted I take a loss in available output power, but I’m still able to make the difficult to drive Betas sing rather loudly. Again, it’s a dream amp. You may find an amp out there with more power, but an amp that beats this amp in sound quality and flexibility in sound characteristics is next to impossible. Bob is right. This is his best work. Bob as I do not listen to vinyl and I know the Citation (I) was geared mostly for vinyl. Is there another preamp as good as the Citation for us non vinyl folks? Currently I’m running a solid state Mc C500. Nov-08-11
A: Heynow', I have to say......oops, I already answered this question, oh well, twice is better than once. Bob Carver
Q: For those who are a little gun shy about the sound of these amps…I have a pair connected to a pair of Infinity IRS Betas and I think they are THE most outstanding sounding amps around. The bias adjustment Bob has implanted is to die for (because of the DC restorer mainly) and you can dial in the amount of Tubeyness you like with the bias control. I have my bais knob dialed all the way down and get the full tubeyest of tube sound. Granted I take a loss in available output power, but I’m sit able to make the difficult to drive Betas sing rather loudly. Again, it’s a dream amp. You may find an amp out there with more power, but an amp that beats this amp in sound quality and flexibility in sound characteristics is next to impossible. As Bob said, “…this is my best work…” It is. Bob as I do not listen to vinyl at all and I know the Citation (I) was geared mostly for vinyl. Is there another preamp as good as the Citation for us non vinyl folks? Currently I’m running a solid state Mc C500. Nov-08-11
A: Hi '310, Thanks for taking the time to write about your (my) amp with so much passion and enthusiasm. I appreciate it a lot and it means a lot to me. As for a preamp, you love your '500, so stay with it. If you do get a chance to listen to a tube preamp, do so and enjoy the music! Thanks again, Bob Carver
Q: I love your amps! OK....I have a pair of McIntosh MC60s and a pair of MC30s and I'm thinking about selling them to hopefully be able to purchase a pair of these amps....these are ART to me, if they sound half as great as they look, they will please! My question is this, will you be selling another pair of these within the next six months? Last question, I saw a Citation Preamplififer that you'd restored sell on Ebay recently.....I need a preamp....what preamp would you suggest please? Or do you build a preamp? I watch the Marantz 7, Mcintosh c22 go for so much moolaaa....lafeyette 600 is more my price range....what do you think is a great preamp? Cheers. if it matters....My speakers are old JBL studio monitors, 4345, and 4435, L300, etc....and some altecs in there....mostly vinyl.....any advice or info from you will be greatly appreciated......I want my name on two of those placques! Thanks and keep up the awesome work! Rob in KCMO Nov-07-11
A: Hi Rob, Thanks Man, Sometimes I look at them and think they ARE works of art - at other times I look and see a big red strawberry candy. As for the sound, these amps are my best work, and the sound is so good it's not to be believed, if I may say so myself. I do plan on selling some more right here on eBay , definitely in the next six months. Hopefully sooner. I suggest the Citation I. I have several of those, as well as the Lafayette 600 - both were designed by Stu Hegeman, a rare and true genius. They sound almost the same, but the Citation edges it out just a bit. The Lafayette was a "price point" product for Lafayette, whereas the Citation I was a no-holds barred masterpiece for the Citation division of harman kardon. I don't build a preamp, and I don't need to 'cause there are several superb preamps out in the world today. Hope this helps. Warmest and best, Bob Carver
Q: can kt88 stands for such high plate voltage which pre set for kt 120 if im not wrong the amp is designed at 700v plate ? Nov-04-11
A: Hi gassies, Classic, vintage KT88's are rated for 800 volts on the plate, and in actual use can easily stand off three times that, or 2,400 volts. They have to be able to stand off at least twice the plate voltage of 800 volts. That's because in a push-pull circuit, when the plate of one tube is pulled toward ground as it's turned on hard, the other tube's plate is going to be driven to 1,600 volts (twice the B+ voltage). In actual practice it won't be quite double because the opposite tube cannot turn on 100%. But it is close! I have designed my amp to operate with about 700 volts on the plates. Very conservative, and a walk in the park for these mighty KT88's or KT120's. Great question! Warmest and best, Bob Carver
Q: Hi bob! I'm MANNY,I have been a big fan of yours since the 80's when the late julian hirsch used to make so many and wonderful reviews on your designs. Back then I used to only dream of ever getting any of your designs.I was a young airmen,now an old army wounded soldier still in the hobby.I collect your old carver corporation amps for years, all the solid states from the 1.5t to tfm 753 including some of your sunfire products like the TGR 401 used except the crm2. I've always wanted to own your tube amp designs but it's way outside my budget although everything you make should be at least 5x higher in pricing. I was wondering if you plan on developing lower price more affordable tube amps or integrated tube amps that some of us lower income hobbyists can afford below the $2k mark.You're a genius in my opinion. There's this dr.dao who mocks all high end amplifier designers from dakiom and it disturbs me a lot. He's basically saying all the developers you mentioned are wrong? Nov-04-11
A: Hi Manny, What a blast from the past - I love it! Don't stop;I'm glad you have been enjoying my designs for so many years. As for a smaller amp that will be under $2k dollars, I'm thinking about one now, but it will not be soon I am afraid, perhaps late next year or early 2013. Oh well, what's a year and a half compared to the last thirty? Hey man (should I say dude?),thanks for writing,and I have to say that we amplifier designers all are trying to get it right; designing a great amplifier is tough, non trivial, and always (mostly) rewarding in the end. Best wishes and warmest regards Manny, Bob Carver
Q: I have played guitar for 32yrs. owned marshall,orange mesa boogie,fender, wtf...they all sound poorly,old.............needing a re-build. I make the amps for guitar we should of made years ago,I do not wind my own transformers,hammonds are fine from canada.only the best parts EL34 output tubes X2 and all American parts,sprauge,corneil dubler I will blow you away with this design,Ken Fischer was one of my hero,s Nov-03-11
A: Hi 'noon, Wow! 32 years and still in the arena. You remind me of me. I agree, an old vintage amp with some loving rebuild will surprise you with the amazing sound we can get from the genius designs of yesteryear. It's super rewarding to take the time to restore and rebuild an amp, then have it sound great and so much better than when we began. Ken Fisher is a hero no doubt to many - my hero is Stewart Hegeman from the past, and my contemporary hero is Tim De Paravicini. Both are geniuses. Thanks for writing. Keep building, Bob Carver
Q: Hi Bob, You say "Check out a pair of my Cinema Ribbon loudspeakers - you can hold them in the palm of your hand, but they play as loud as the Amazings did and the sound and sound scape are very much like the Amazings" what might the part number be of the ones you are referring to? Regards, Jay Fletcher Nov-02-11
A: Hey Jay, they are called the CRM-2, which stands for Cinema Ribbon and they come two to a box. If you want to read up on them go to the Absolute Sound and do a search for Bob Carver interview and a beautiful story about my CRM-2's written by Robert Harley. I cannot remember the issue number, but it was a year or two ago. I'll find the issue and sneak it in with my answer to a question that will have nothing to do about ribbons. Stand by. Your old friend, Bob Your old friend, Bob
Q: HI BOB you look younger in every photo i see you in. ps MY systen is made up of your equipment and tim"s the best around. forevermusic414 Nov-02-11
A: Hi '414, I'm glad you think I look younger - you can be my friend forever! In truth, I was old when Atlantis sank. Still, those photos were taken a couple summers ago. Yea for Tim, me and you, the best sound around! Warmest and best, Bob Carver
Q: Hi Are you actually Bob Carver, the founder of Carver Corp that used to make some of the best HiFi amps and speakers ever. The one that gave use the Amazing, AL-III, Mt1.5 etc? I wasn't that lucky to own AL-IIIs but I head them once in the 90s and I could not believe how good these speakers sounded. I ended up with Cinema System 5.2 and 5.1 surrounds and have been very pleased with them for the last 10 years. I would only change them for a pair of AL-IIIs . PS If you ever decide to make AL-III again know that you got one buyer already, me All the best and thank you. Nov-01-11
A: Hi 'sdg, It is I, the real Bob Carver. Just to make sure, I'll stand up and pinch myself. OOwwwchhh! Yep, it's me alright so count me in. I'm happy to hear about the Amazings - Man, that was long ago, yet still they stay in your memory. Check out a pair of my Cinema Ribbon loudspeakers - you can hold them in the palm of your hand, but they play as loud as the Amazings did and the sound and sound scape are very much like the Amazings. Thanks for the trip down memory lane, Bob Carver
Q: -Hi Bob, I purchased one pair of your previous incarnations of this amp that run KT88s and produce 240 watts each. The current incarnation is using Kt120s and produce 305 watts each. I am wondering if KT120s could be run in the "older" 240 watt amps? What about the KT100mkIIs? Still enjoying the music - thanks! -Gary Nov-01-11
A: Hi Gary, Long time, well, not so long. Glad to hear from you and that you are still in the arena. And still enjoying the music. As for the KT120's, if you got 'em, use 'em. The power will indeed increase, and will increase substantially with a difficult to drive speaker that exhibits large impedance swings. The power will fall somewhere between 305 watts and 240 watts rms. Adjust the bias for about 20% more idle current than you had with the KT88's. Just plug them in and turn the bias control. That's all you have to do. Any more questions, let me know. Your old friend, Bob.

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Sold 11/29/11 for the stunningly low price of $5655.55 is the latest pair of 305 watt 'Black Beauties' from Bob Carver. Not a lot of activity on this auction perhaps due to the impending Christmas debt most folks will face. Nevertheless, here's the very short Q&A:

Question & Answer Answered On
Q: Hi Bob, Jay here... Happy Thanksgiving... One small question about those two awesome 305's that you are selling there... What might be the little toggle to the right front corner? Is it a new addition? I haven't noticed it before... Your friend, old friend, in Okla. "jay" Nov-25-11
A: Hi Jay, Happy Thanksgiving! It's the meter range switch. It's been there all along, but I know what you mean; it's hard to see and it certainly does not stand out. sharp eyes! Your very old friend, Bob
Q: Hello I am fan. It sounds like you built these just to drive Apogee Speakers. Did you? And will any of your solid state amps drive a 2 ohm speaker? -Mark in LA. Nov-22-11
A: Hi Mark, I love questions like this! I'll make my answer short and sweet and juicy like these nutz.. Sort of - yes and no, and yes. Thanks for writing. Best wishes and warmest regards, Bob Carver
Q: Hi Bob, I like to know if you have listen to or benchmarked your amp's sound against the 200w Antique Sound Lab Hurricanes using 8 KT88s vs. KT120. Thanks Ed Nov-22-11
A: Hi Ed, I have listened to the Antique Sound Lab amp with KT120s, and it sounded great. The only problem was that the 'Sound Lab unit was not set up for KT120 bias and the idle current tended to go way too high. I chickened out and shut it down because the plates were beginning to glow red, but before I turned it off, the amp sounded beautiful. Hope this helps. Warmest and best regards, Bob Carver

From the auction that started this week:

Question & Answer

Q: Hello, Do you think this amp would be a good candidate to match with a passive preamp? Thank you May-26-12

A: Hi 'uos, Yes I think this amp would be a good candidate for a passive pre-amp. However, in order to use it happily with a passive unit (gain = 0 dB), you need to ask me to increase the gain of this power amp to make up for most of the lost gain in the passive. That is no sweat, and is easy to do. If you win my auction, let me know, and it shall be done! Great question! Warmest and best, Bob Carver

Q: Hi Bob, How about offering kits or similar type tube amps for sale to the general public? Also, what brand/model chassis is this baby built on? It sure is a beautiful looking amp. Thank you. Wish me luck in the bidding. Ed May-26-12

A: Hi Ed, Good luck, I have my fingers crossed. I can tell you might just win. Close your eyes, cross you fingers, jump into the air, and when you come down, you will have won! Don't forget to open your eyes though! This is a forty year old chassis originally designed for a big beautiful jukebox, the kind that has colors and bubbles going up and around its front glass. The model is a T-4550,and I'm not saying the brand. You can guess though, and probably get it right. Thanks for writing in. Warmest regards and best wishes, Bob Carver

Q: My name is Andrew I am a huge fan wanted to say Hi. I love my CT-23 and I have a MXR 130 I am waiting to find a M-500 T on ebay soon. Can you answer a question Which amp solid state sounds like a tube amp people on here claim the TFM 55. is all TFM's sound like a tube amp. I am happy with my Ayon Orion 2 which is winning best in show all over America as far as a tube amp is concerned. But for watching T.V. and movies will a TFM or any M-t do the trick for me or TFM's or what Thank You. May-26-12

A: Hi Andrew, The amps that I made to sound as close as I could to a real tube amp were the TFM series. Any one of those amplifiers, within its power rating, will sound as close to a tube amp as a solid state amp ever can without actually being a tube amp. I am honored that you took the time to write in, and for telling me about all the Carver equipement you have or had. The M-500 is a wonderful amp, and if you can get one on eBay, go for it! Warmest and best, Bob Carver

Q: Bob, I wanted to thank you for your contributions to the quality of lives of the many audiophiles who have truly enjoyed the way you have enhanced our listening experience through your engineering brilliance. I came across your engineering excellence in 1987 when I experienced sonic holography in the Carver system and it was truly a life changing experience. I just wanted to let you know you have touched our musical hearts in a way that no other individual has ever done and for that, I truly appreciate the contributions you have made to the industry and for raising the bar to levels that only others can dream of. I have been a Carver fan and fanatic ever since. I was bragging to my neighbors the other night about the sonic hologram and they listened and were amazed so you have a new legion of fans, both young and old as my 8 year old son Caleb can attest. I became an audiophile at that moment who has judged other systems by the standard you set. Rock on my friend!! Shannon May-26-12

A: Hello Shannon, What beautiful sentiments - I am honored beyond belief. I don't know what to say except that after I read this wonderful missive, I felt like a minor wizard floating on air. I'm certain that if I wore a dark robe and walked about, you could see that my feet did not touch the floor. Still, you would have to peek under the robe to see my body just above the ground. You have made my day - I guess I'll have to stay in the arena for some time to come. Thanks from the bottom of my heart, Bob Carver

Q: Hi Bob, I have heard lots of people say that the only way to go with tube amps is pure class A, and that class AB invites lots of distortion that destroys the sound of the amp. I have seen that all of your tube amps on sale on eBay are push-pull class AB units, and I was curious how they match up to pure Class A amps. Thanks! May-22-12

A: Hi 'J, Great question, and a great question deserves an extended answer. But first, a bit of history. Long ago, sometime in the 1930s, it was not possible to get rid of crossover distortion in class AB designs. As time went by, many brilliant and talented designers worked and toiled to build a Class B or AB output stage that held the promise of high power with the low distortion of a class A output stage. At the time, a class A output stage was the only way that low distortion could be achieved. As the years trolled by, developments in biasing, vacuum tubes, output transformers, and driver circuits have yielded results that allow the low distortion (lower actually) inherent in Class A with the power output of class AB. About four or five times as much power. Still, a long held false belief exits that says "Class A, Class A, class A," but it is left-over thinking from 1930 and 1940. Not true anymore. Honest. Read on. When we listen to a vacuum tube amplifier, we do not hear the "class A ness" or the "class AB ness," rather we hear the fundamental characteristics of the amplifier, however they are developed. It is easy to build a class AB amplifier with the same, exactly the same characteristics as a class A, if that's what we want to do. And vice versa. I don't like the sound of a class A amp, not because it's class A, rather because it is almost always very low power. I like lots of power, substantially more than three to eight watts. Whenever I listen to a low power class A amp, the quick onset of overload just disappoints me enormously. Especially when a nice Class AB amp can possess the same purity of sound and simultaneously have much more power. We can have our cake ..... Thanks for writing in and for a really good question, Bob Carver

Q: Hi Bob, You mention that you are able to do some tube rolling with this amp changing the output tubes (7868), can the other tubes be rolled safely without altering the amp (rectifier and 12ax7). Thanks! Regards, May-21-12

A: Hi Tom, Absolutely! The amp will arrive with EH7868s installed, and four extra Brimar 7868s. All brand new, except for the Brimars which are NOS. The front-end tube, normally a 12AX7 may be exchanged for a 12AU7, 12AZ7, 12AT7, 7025, 12AY7, 12BH7, and actually many others. The ubiquitous 12AX7 has about 25 substitutes if memory serves me. You can get a tube substitution guide on-line, or even from eBay. The 5U4 may be replaced with a 5AR4, 5R4, 5AU4, 5V3, even a 5Y3. The most fun though is to "roll" tubes within the same number but different manufatures. Replacing the RCA 12AX7 tube with a Telefunken 12AX7 will change the sound - somtimes making it better, often not. It is soooo much fun to try, especially in the late evening far into the night with a a small group of audiophile friends. Great question, Bob Carver

Q: Hi Bob Jay from Oklahoma... Welcome back to the big world of e-bay, have been missing you... Another good looking "Baby" you have there... Best Regards, "jay" May-19-12

A: Hi Jay, you always make my day! Bob Carver

Q: Bob, I have 2 lightstar preamps. One is working, the other is not. I have found the problem to be the Motorola MC68HC711E9CFN2 micro controller on the control/display board. I am wondering what the chances are of me being able to get one of these? A programmed one would, of course, be best. You can call me directly at 607-351-7084. I look forward to hearing from you whether or not it's possible to get this chip. I am not a shop, just a carver enthusiast. I am also a forum member at carveraudio.com, my user name is natektronic. Thank you, Nathan Kabelac May-19-12

A: Hi Nathan, Boy, it's an old chip, but I just know I can find one somewhere. Give me a few days and I'll see if I can get one, or at least find out where you can find one. Stand by, and e-mail me here again on Wed. Wish me luck! I'll wish you luck too. Bob Carver