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..
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..
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:
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...
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.
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.
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.
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.
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!
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!
Attachments
Hi;
I bought the pair for $450.00 can. Which is a fair price, i think, considering that the caps did not leak in one of the amps, but the guy had them replaced anyway. When they arrive, i will redo the boards cleaning with an ultrasonic cleaner and a aquous base solution, in order to neutralize whatever acidic residue that may be remaining on the boards.
The pair looks like an early production, with very low serial numbers, so the boards may be made of bakelite, instead of fiberglass. The capacitor acid may have soaked into the bakelite. If i can't clean them throughly enough, i will have to drill microscopic holes between some of the copper traces, in order to remove some of the parasitic resistance remaining on the board. This should fix the problem. Will also replace the servo IC . 😊
I bought the pair for $450.00 can. Which is a fair price, i think, considering that the caps did not leak in one of the amps, but the guy had them replaced anyway. When they arrive, i will redo the boards cleaning with an ultrasonic cleaner and a aquous base solution, in order to neutralize whatever acidic residue that may be remaining on the boards.
The pair looks like an early production, with very low serial numbers, so the boards may be made of bakelite, instead of fiberglass. The capacitor acid may have soaked into the bakelite. If i can't clean them throughly enough, i will have to drill microscopic holes between some of the copper traces, in order to remove some of the parasitic resistance remaining on the board. This should fix the problem. Will also replace the servo IC . 😊
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.