Amp problem - Sounds drops out of one channel


Related to my other thread where I mentioned my amp needed repair...

I've got a Classe CAP-100 which I'm using to drive Revel M20 speakers.

I've recently been having trouble where the volumne in one channel drops out significantly or entirely at low listening levels (I live in an apartment and most of my listening is at low/moderate levels).

If I turn up the volume control the sound will return, but when I turn the volume back down to normal listening level it will eventually drop out again.

It can happen in either channel, regardless of source (CD or turntable).

Anyone got a clue what this might be? Also, does anyone have a recommended stereo repair shop in New York City? I bought the amp secondhand from an out-of-state dealer years ago. I'd rather not ship it to Classe in Canada if I can get it fixed locally.

Thanks in advance!
big_a
Sounds like you damaged some transistors somehow (short the amp, over drive it or something). You should also check your speakers carefully or whatever was connected to the amp when you suspect it may have been damaged.

In Class AB designs they will run Class A at low levels and that seems to be where your problem lies since the problems are mitigated at higher outputs where other transistors are conducting (Class B amp section)

Note that Class A sections get hotter when they do nothing and cool down when they are worked harder - and this may be a related aspect of your probelm (why does it sound ok when tuned up and then fail when at low levels or off).
I`d clean the volume control by spraying w/ tuner cleaner or DeOxit. If that fails try Analogique on W20 St. They`re authorized repair for Mac, Adcom, et. al.
For repair, Ben Jacoby in Brooklyn is excellent.
http://www.highendaudiorepair.com/ben-jacoby.html

good luck.
Porziob: I'm with Porziob in that it is probably your preamp volume control.. turn the volume up and I bet it doesn't drop out... Cleanit or replace it.