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Anyone have this kind of problem with their amp?

I own a Classe CAP-101 integrated amp that I bought used about 10+ years ago.  Recently, it's developed a problem where the right output channel doesn't operate.  Sometimes, the amp works just fine.  But at other times, the right channel won't operate when I power up.  At still other times, there's no issue when I power up, but the right channel will stop working after a variable period of time, sometimes ten minutes and sometimes thirty or even more.  Occasionally but not frequently, after the channel has stopped working, it will resume working after a while, continue to work for a time but then may revert to not working.  When the channel stops working, turning the amp off and restarting it, and/or unplugging and replugging it, does not restore operability.  I've checked and re-checked my connections (bare wire) without any effect  

It's not my other equipment, because I've inserted another integrated without any issue.

I've taken it to a repair shop but the tech couldn't replicate the problem, so he couldn't diagnose it.

In the past, when I've contacted Classe customer support by email about a previous issue or with a question, I've never even gotten a reply.

Any thoughts/advice?  Thanks in advance.

Jim
jimcrane
mrdecibel
3,063 posts
 
Not familiar with this unit, but looking at photos posted on this unit, does the design incorporate output relays ? The problem described, ime, sounds like this might be the issue, as relays have a notorious history of failing. Or an output current limiter circuit. Of course, it would need to happen during a test bench check, as experienced. Possibly, a weak solder joint, as well. Just some thoughts.
cakyol's avatar
cakyol
940 posts
 
Does your amp have a relay based DC protection circuit ?  It may be falsely kicking in & latching ?


stereo5's avatar
stereo5
6,377 posts
 
It's a cold soldered joint on the circuit board, very common with this amp.  I had that problem with the CAP101 and 150, both the same.  Had to send my amp back to Classe in Quebec for repair.
amg56's avatar
Ag insider logo xs@2x
amg56
887 posts
 
@jimcrane I might suggest you have a temperature sensitive open circuit in an amp component or crack in a solder joint which expands/contracts with temperature. Or there is a component in the middle of failure. At least you can isolate the operational area of the failure area.
skyscraper
829 posts
 
Jim, I've no helpful suggestions, but had that identical problem with my Phase Linear 4000 Preamp's right channel off and on for over forty years. I took it to three different repairman over that time, and even back to the Phase Linear factory, which was located outside Seattle back in the eighties, not too far from home then. None of them could find or engineer a permanent solution to whatever the problem was.

A bunch of replacement caps helped it keep going for a while the last time around. The final solution came last year in the form of a dumpster. I gave away the matching Phase 400 amp, which was still going strong and never a moments trouble. I wish you the best of luck finding a better solution in a much shorter amount of time.

Mike
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