Carver M1.0t MKII mod thread (lets talk about it).

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EndersShadow
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Carver M1.0t MKII mod thread (lets talk about it).

Post by EndersShadow » Mon Sep 08, 2014 3:51 pm

So I've heard many things at the 2 different forums regarding the MKII mod's to the Carver M1.0t and M500t amps.

I figured I would start a discussion that would allow all members of this site to comment on their concerns, and hopefully some of the guys smarter than me who have done these mods can discuss them.

I realize this particular mod is a point of contention between both forums.

I am HOPEFUL that this thread can remain civil. Lets keep our discussion on the actual implementation of the MKII mod and actual facts about its implementation.

Here is a thread that has been referenced where Rolland and RichP discussed his MKII modifications.

viewtopic.php?f=8&t=6996&p=75747#p75747

I wont attempt to be smart enough to understand it all, but lets talk numbers, physics, heat, etc. I hope to some extent the discussion in this thread can help provide a source of factual information on the modification to be used as a reference.

So if you have facts about why the modification is safe, concerns about its implementation, etc, discuss them here.

But lets keep it civil.
"You were on my Ignore List, but you are too damn entertaining, like a circus monkey, so I took you off" - H9
"We shouldn't laugh at people like you, we should pray for them. You have my prayers for a speedy rehabilitation you sad, silly little man" - Jstas

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EndersShadow
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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by EndersShadow » Wed Sep 10, 2014 6:02 am

Bump...
"You were on my Ignore List, but you are too damn entertaining, like a circus monkey, so I took you off" - H9
"We shouldn't laugh at people like you, we should pray for them. You have my prayers for a speedy rehabilitation you sad, silly little man" - Jstas

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radioeng2
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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by radioeng2 » Wed Sep 10, 2014 6:29 am

Dan,

You've got a topic that is interesting, but I think you've caught many, very busy. A big share of the folks around here are on the road right now. They've been busy packing the cooler, picking up flashlight batteries and lookin' for the door! \:D/

Mark
I was there "At the Fest!" Hope you were too!

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EndersShadow
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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by EndersShadow » Wed Sep 10, 2014 9:13 am

radioeng2 wrote:Dan,

You've got a topic that is interesting, but I think you've caught many, very busy. A big share of the folks around here are on the road right now. They've been busy packing the cooler, picking up flashlight batteries and lookin' for the door! \:D/

Mark
No worries Mark... I actually meant to bump my amp listing not this one lol..
"You were on my Ignore List, but you are too damn entertaining, like a circus monkey, so I took you off" - H9
"We shouldn't laugh at people like you, we should pray for them. You have my prayers for a speedy rehabilitation you sad, silly little man" - Jstas

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Nahash5150
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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by Nahash5150 » Fri Sep 26, 2014 6:26 pm

RichP has retired from the mkII project due to ill health. I am now the authorized mkII tech. I'm available for any questions.

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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by B-Man » Wed Oct 28, 2015 6:27 am

I don't know if this topic is still of interest, but I will add my experience with the MKII Opt 002 M1.0t.

Back in 2012, I was talking with a friend who was asking me about re-capping his Acurus amp. Silly to say, but I have had my M1.0t amps since '86 and never thought about re-capping them. They have been played every week over the years and I thought they sounded just fine. (Each one in mono mode, driving a pair of AL-III+s).

That got me to searching for replacement capacitors and such and, through a convoluted Google rabbit-hole search, I ended up at Rich's CarverSite. I emailed him about upgrading my amp (which includes, obviously, replacing the electrolytics) and he gave me a typical Rich response - curt, to the point, borderline rude (IMHO, especially for a business reply) saying he had a waiting list and I had to get on it. I asked him how much for the service and got a snippy reply saying to look at his web site for pricing. I did not realize there was a separate MKII site for amp upgrades at first. Anyway, I said to myself "what a dumb-ass" and decided that no business was going to get my money AND treat me like that, so I started reading all of the info on the MKII upgrade process. I ordered enough parts to update / upgrade both amps. This was in January of 2012. The parts came in and I updated / upgraded both amps in February.

Since that time I have been working out of my house. What that means is I turn the system on at 7:00 AM (works as a wake-up call for the lady of the house) and it plays until some time in the evening, usually around 7:00 PM or so, when she turns on the TV. At least two or three times a week we stay up later and play music, at pretty impressive sound levels. On weekends we often will have marathon listening sessions that last 4 - 6 or more hours.

I can tell you that even after four hours of sustained jamming sessions, the amps are just warm to the touch. They are dead silent, they sound awesome and there is definitely more "oomph" than before the MKII Opt 002 treatment was applied.

Earlier this year I opened both amps up for a visual inspection and to check / adjust the bias settings. Both amps look perfect inside - no burned spots on the PCB, no discolorations, etc. I did re-adjust the bias on one channel of one amp (it was a bit high) but outside of that they have been played loud and hard for almost three years now and show no signs of distress. There are quite a few folks on the other site that have modded amps and I've yet to see a report of a failure or problem (other than a few amps modded by a former member who seemed to be more interested in the money than the quality of his work).

If you have a M500 or a M1.0t and it is original, it is due to be refreshed. For the small cost of the MKII upgrade, you can hardly go wrong by adding it in when you replace the electrolytic caps. Like Rich pointed out, the rest of the transistors and diodes that get replaced are of much better quality / capability than was available when these amps were new. Even if you don't bump the rail voltages up, you will have better components inside for the next 30 years of use.

WOW - Who would have thought they'd still have their amp 30 years after they bought it, still working like a beast ? Bob sure did an awesome job - it was a bucket list item for me to meet him and I finally did at Carverfest this year. :D

Sorry for the long post. Just thought I would share my experience.

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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by Nahash5150 » Thu May 05, 2016 6:38 am

I just came across this today on Rolland's site:

"Carver Power Amplifier Modifications
Although the Carver line of amplifiers have more than enough power to drive any speaker. Including speakers with difficult to drive, low impedance loads such as the well-known Infinity Kappa series. We offer what would be called the "Silver-Seven" upgrade and the Carver MK-IV. This upgrade for the Carver MK-IV involves doubling up the output transistors for more efficient, low impedance drive, high current steering ridges, polypropylene bypass capacitors in the signal path. Re-aligning the triac firing angle and reducing the current limit circuit to allow maximum use of the SOA in the devices used in the M-1.0t power amplifiers. The front end can also be modified if the customer prefers the sound of the TFM series amplifiers, such as the TFM-55 and TFM-55X. For further details, please feel free to give us a call about these modifications."


Apparently he's been converted! =D>

But this strikes me, "Re-aligning the triac firing angle and reducing the current limit circuit to allow maximum use of the SOA in the devices used in the M-1.0t power amplifiers."

That deserves some explaining, because I certainly don't understand why any of that is necessary at all.

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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by Brucest » Wed Jun 29, 2016 10:45 am

Hi,

I have two MKII 1.0t's done by the other guy, not Richard P, years ago. One popped awhile ago and I contacted the fellow, whose name I can't remember, and he was in the service out of the country. Now the other one has. Let me explain what happened. I was rewiring my system and the Carver was connected to the wrong outputs from my prepro. I went to disconnect the wrong connections and forgot to turn it off. Bad noise. I would have expected the worst was a blown fuse. But the amp won't turn on. Switching in on yields a faint hum. Any thoughts, suggestions on repair or anything I can do?

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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by Brucest » Wed Jun 29, 2016 11:04 am

BTW I checked the other one. It turns on with the red lights, but a yellow light also comes on.

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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by Robert R » Wed Jun 29, 2016 3:30 pm

Brucest - Contact Nahash5150 f0r information on problems with your M-1.0t Mk II amps. He's busy, but very good. Done right, these amps are extremely reliable.

There was a guy who rebuilt quite a few of these and who had a reputation for cutting corners - maybe that's who did yours.
Last I heard he was not on any forum except his own private one [as a sometime editor, phrases like "private forum" really irk me].

Robert R
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Re: Carver M1.0t MKII mod thread (lets talk about it).

Post by wrf » Thu Sep 29, 2016 7:17 am

Both amps from Brucest were done by "The Other Guy" - most noted for his practice of selling them on Ebay and his colorful use of heat shrink in their construction. Both had counterfeit 2SA1302/2SC3281 devices that had blown. Both had counterfeit TIP35/TIP36 devices - high rail commutators. Those devices had blown in one amp. Further, one amp had a failed thermal cutout in the mag coil that had been bypassed.

One amp has been repaired and returned to service. The other will be scrapped as the failed thermal cutout deep inside the mag coil renders it useless. Bypassing it creates a safety hazard.

The devices were confirmed as counterfeit by breaking them open and examining the die size. The die was about 1/4 the size of the die in a legitimate device.

It's easy to get caught by counterfeit devices in this world. But lack of testing was the real issue with these amps. Both would have failed had the maker tested them at load.

Not clear who bypassed the thermal cutout, but the last one to touch the amp was "The Other Guy". At worst he bypassed it. At best he didn't notice it was bypassed and passed along a safety hazard.

This is not the first time I have repaired amps with counterfeit parts from "The Other Guy". If you have an amp from him you can contact either myself or Nahash5150 for guidance on how to check for counterfeits. If it has already failed or if you detect counterfeit parts we will repair it for a nominal charge. It's in everybodys interest to get these amps off the street.

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