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Thread: Blown Adcom 555 II

  1. #1
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    Blown Adcom 555 II

    Ok, well this is another reason I'm not found of old electronics.

    My Adcom blew and is dumping Dc into the speaker circuits and the fix is $240.

    On E-bay a typical version of this amp is worth about $275-300.

    What should I do here - toss it inthe trash or take to another repair shop?

  2. #2
    Senior Member BMWCCA's Avatar
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    This is how most people (not us!) would list it in an Ebay auction:

    Adcom 555-II amp. Mint condition. Lights up. No way to test it. Sold as is. Arc-welded output wiring but doesn't affect the sound.

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    Quote Originally Posted by robertbartsch View Post
    Ok, well this is another reason I'm not found of old electronics.

    My Adcom blew and is dumping Dc into the speaker circuits and the fix is $240.

    On E-bay a typical version of this amp is worth about $275-300.

    What should I do here - toss it in the trash or take to another repair shop?
    It is painful to hear that you might toss it in the trash. They were a great amp in their day.

    The safe bet is that the output devices would need to be replaced at the very least. Then you would need to find out why they went bad. So it is understandable why the repair shop wanted to charge you that kind of money.

    If you are seriously thinking of getting rid of it, I could use the chassis and transformer. I am a DIYer and have some projects in mind. I live in CT and could pick it up. PM me if you like and suggest a fair price.

    On a positive note, you were lucky the DC did not take out any of your drivers.

    Thanks,
    -Tom
    Last edited by withTarragon; 02-24-2009 at 12:47 PM. Reason: typos

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    I did not discuss the details of the mortality with the shop but I assume you assume the output transformers are toast.

    ...I've only had the amp for about 4 months or so. At first I did not like it much because the LF material seemed to be over emphasized.

    Since I am now playing the basement system with a different amp, I kinda miss this, however.

    Oh well, I'm done buying 20+ year old electronics - been burned to often.

  5. #5
    Senior Member Russellc's Avatar
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    Quote Originally Posted by robertbartsch View Post
    I did not discuss the details of the mortality with the shop but I assume you assume the output transformers are toast.

    ...I've only had the amp for about 4 months or so. At first I did not like it much because the LF material seemed to be over emphasized.

    Since I am now playing the basement system with a different amp, I kinda miss this, however.

    Oh well, I'm done buying 20+ year old electronics - been burned to often.
    while I know Mcintosh has output transformers on many of their Solid State units, I wasnt aware that Adcom had output transformers? Perhaps you mean output transistors?

    Russellc

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    ....right - output transistors - 16 in all I think!

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    Heather [Senorita member] hjames's Avatar
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    Quote Originally Posted by robertbartsch View Post
    ....right - output transistors - 16 in all I think!
    yeah, so post it to ebay as having blown output transistors and see what happens ... Can't hurt and beats just tossing in a dumpster ...
    If you're honest about it when you post the ad, that's a reasonable thing to do.

    caveat - before you joined I bought a "tested and working" JBL/UREI poweramp that arrived in a box with just a smidge of popcorn - this is a HEAVY pro amp .., it smelled and when I opened it I found evidence it had cooked pretty thoroughly. After 10 weeks and a lot of yelling and fighting with ebay and Paypal, I did get a refund - only because I disputed the charge on my VISA card!! But THAT seller was just SCUM.

    See - http://audioheritage.org/vbulletin/showthread.php?t=17362&page=3
    2ch: Oppo, JoLida 502CRC, JBL L212, 18ti,240ti; Heath AS101, Von Schweikert VR4
    7.1: Oppo BDP103D, B&K, UREI 809A, JBL B460

  8. #8
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    Robert - didn't you recently put a Crown amp into protection mode? What are you doing that causes so much stress to your amplification?

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    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by clmrt View Post
    Robert - didn't you recently put a Crown amp into protection mode? What are you doing that causes so much stress to your amplification?
    He was trying to see if the new amps could run in a home environment with their fans disconnected. It seemed to work for the first one, not so well for the second. His other thread should be still around if you're interested.

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    BMWCCA:
    Well that is a good question.

    I am not forcing these amps to high levels of power. The Adcom is a 20 year old piece of electronics that I purchased from Fleebay. After a few months it just crapped out and now pushes DC into the speakers.

    The repair shop now claims the power supply needs to be replaced.

    The two identicle Crown amps is somewhat misterious. Both amps are refurbished units sold by the factory with full 3 year warranties. One amp runs ice cold. The other is very sensative to heat and needs a cooling fan to keep it from shutting down from thermal heat.

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    Senior Member Ducatista47's Avatar
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    I wonder if it is not old electronics but solid state electronics generally that are the problem.

    I think that bipolar transistors in power amps anywhere but in the power supply have always been a loser. Some progress has been made since the days when their biggest accomplishment was avoiding thermal runaway, but not that much and I have personally given up on the approach.

    Me, I don't like the way they sound, I don't need the expensive repairs and the threat of DC, and with the alternatives available today I was very happy to say good riddance.

    I have newer gear, all tube right now but I am about to start dancing with MOSFET's too. None of this is costing an arm and a leg and I get great results without expensive NOS tubes or super duper grade new ones.

    It seems to me that the promised "reliability" and "superior sound and convenience" of bipolar silicon has played out like sending all the manufacturing to China. Cheaper now but more expensive in the long run. Nothing is really better but there are a whole lot of problems that were not mentioned when we signed on to the deal. Being awash with solid state gear past and present does not bestow legitimacy on it. It just makes it common, familiar and seemingly cheap. But not better or even good.

    If one really feels he needs gobs of power to drive high efficiency speakers (???), feel free. Go solid state. Been there, done that, thank you.

    Clark
    Information is not Knowledge; Knowledge is not Wisdom
    Too many audiophiles listen with their eyes instead of their ears


  12. #12
    Senior Member duaneage's Avatar
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    I labored over an amp for three weeks, ordered all kinds of parts, went through and replaced anything that looked even questionable. I turned it on and it ran for 10 minutes before popping. Really disheartening. I feel once a SS amp takes a dive the cost and trouble of repair is not worth it. There is a lot of energy in there and when things get weak they die in a spectacular manner

    As to eventually death, MOS-FET and other thick film outputs are sensitive to static, and can also develop "holes" in the substrate over time. Add to that dirty heat sinks and dry silicone compound on the transistors and it's possible they can just go out. Although we all romance over how things were made better back then, I think quality has greatly improved today when it comes to transistors. Objective sound quality aside, it's a reasonable argument that a modern amp for 300-400 dollars would do just fine and come with a warranty to boot.

    Somewhere out there is a guy with a working Adcom in a crappy case that needs a new chassis, or someone that wants a spare for parts like power supply caps and fans. I would say you should be able to get 100 bucks for the wreck, even with shipping someone will buy it.
    Why buy used when you can build your own?

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    Well I 've owned many tube amps over the years and I would not give two cents for one now.

    The new SS amps built today are quite good and reasonably prices; old electronics are just that - old.

  14. #14
    Senior Member sourceoneaudio's Avatar
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    Quote Originally Posted by robertbartsch View Post
    Ok, well this is another reason I'm not found of old electronics.

    My Adcom blew and is dumping Dc into the speaker circuits and the fix is $240.

    On E-bay a typical version of this amp is worth about $275-300.

    What should I do here - toss it inthe trash or take to another repair shop?

    FYI:
    Adcom does take trade ins of old broken Adcom gear towards a new amp/purchase. The GFA-5500 would be a great replacement, ($1500.00) last retail. If you are not looking to trade in the GFA-5802 is a highly sought after high end power amp, last retail was $2200.00. The average used mint condition price with box $800.00 to $1200.00. (Nelson Pass Engineered)

    http://www.avrev.com/home-theater-po...amplifier.html
    Adcom also is now owned by Emerson. Good or bad I don't know, but old Emerson?
    Jeff-S1A

  15. #15
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    that last piece of news is damn scary

    Somehow Emerson and Pass in the same breath does not seem natural

    Mark
    Think center channel for 250TIs; (2) 108s, a 104 and a 44ti, now what?

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