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Adcom 565 mono block with strange issue
Adcom 565 mono block with strange issue
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Old 14th May 2015, 09:57 PM   #1
thornett is offline thornett  Canada
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Default Adcom 565 mono block with strange issue

Was thinking of purchasing these amps, Adcom 565 mono blocks
The seller informed my today of an issue when I asked about the capacitors being changed and if they had leaked onto the boards,
Got his reply back which posted below. Was wondering if any of you that are familiar with these amps might know what causes this condition of "cone suck" when the amp is shut off? Sellers note below....
Regarding the capacitors, they did leak on one of the amps. The board was cleaned using a neutralizing liquid and the caps were replaced on both amp. On the amp that the caps leaked, it is doing something odd. The amp functions and sounds fine, however when you turn it off, it pulls the speaker drivers in for half second and releases them. I thought this was resolved until last night when I tried the amps out again. The tech that worked on them tried to find the problem and it had decreased to almost nothing so we thought it was resolved until I tried them again last night. The tech believed there was possibly an issue with the part of circuit board that disconnects the speaker circuit when them amps are turned off and that capacitors empty..
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Old 14th May 2015, 10:46 PM   #2
rayma is online now rayma  United States
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Quote:
Originally Posted by thornett View Post
The amp functions and sounds fine, however when you turn it off, it pulls the speaker drivers in for half second and releases them. The tech believed there was possibly an issue with the part of circuit board that disconnects the speaker circuit when them amps are turned off and that capacitors empty.
Don't go there, this could damage your speakers and it should never happen.
The tech seems not qualified to do the repair.

Last edited by rayma; 14th May 2015 at 10:48 PM.
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Old 14th May 2015, 11:17 PM   #3
thornett is offline thornett  Canada
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Yes was thinking the same thing about his tech that he was just guessing but didn't have the hard and fast this is your problem answer.
The thought of blowing up my new speakers doesn't appeal to me in the least
Thought Id try and get some feedback before telling him wasn't interested or getting into spending allot of money getting them working properly all in the name of getting a deal...
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Old 14th May 2015, 11:23 PM   #4
rayma is online now rayma  United States
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Originally Posted by thornett View Post
Yes was thinking the same thing about his tech that he was just guessing but didn't have the hard and fast this is your problem answer.
The thought of blowing up my new speakers doesn't appeal to me in the least
Thought Id try and get some feedback before telling him wasn't interested or getting into spending allot of money getting them working properly all in the name of getting a deal...
If you get the amps for a very good price, you can pay a good tech to fix them right. Don't assume this tech found all the problems, though.
I wouldn't pay more than 1/3 of the going rate for the pair, if I were buying them at all. There should be other similar amps around in better
condition or already restored properly.
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Old 15th May 2015, 12:12 AM   #5
thornett is offline thornett  Canada
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he was asking 650$ CAN dollars for the pair
with this repair problem would 300$ for both be the offer?
have seen them go for 900$ in good shape
in some respects sounds like im thinking of buying someones headache
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Old 15th May 2015, 01:14 AM   #6
rayma is online now rayma  United States
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Originally Posted by thornett View Post
he was asking 650$ CAN dollars for the pair
with this repair problem would 300$ for both be the offer?
have seen them go for 900$ in good shape
in some respects sounds like im thinking of buying someones headache
It could easily cost $300 for a proper repair, even if nothing else is wrong.
Check around for better alternatives, first. I'd say $300 would be the top offer,
and maybe start with $250.
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Old 15th May 2015, 06:27 AM   #7
Johnny Dior is offline Johnny Dior
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Would this not be a bad snubber across the AC power switch? I had this happen with my MCS 3233 where it'd do something similar and the woofer would move when powering off. I upgraded the power switch and also upgraded to a better snubber cap that was rubber coated (think to limit microphonics) and now when powering off, the speaker doesn't move.

I was told elsewhere to leave amp on, then power-down with a power strip to test snubber cap function. I tried it and it powered down correctly, though it picked up the "click" from the power strip's switch. But cone movement was nonexistent. New snubber in and cone doesn't move now.

Granted, this is with an amp from 1977, so dunno if applies or not.
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Old 15th May 2015, 07:29 PM   #8
thornett is offline thornett  Canada
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So the cost of a repair like this?
New switch and a snubber will call the repair tech here and see what he thinks.
Thanks for the feedback
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Old 16th May 2015, 01:59 AM   #9
thornett is offline thornett  Canada
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Had the seller try out the power-bar/strip trick but he told me the results were the same as the cones still sucked in for the half second
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Old 26th May 2015, 01:58 PM   #10
thornett is offline thornett  Canada
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Default New Sony ES gear...

The Adcoms did not end up happening..
So continued my search of audio equipment that would have some power to drive my speakers Rogers Studio 1 which are fairly inefficient at 86db rated 300 watts program.
Ended up with Some SONY ES gear one owner in excellent shape.
Got the amp pre and cd player!
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