Apt Holman preamp problems

My Apt Holman preamp has had the same problem for years...the audio just cuts in and out
for a second, as if some was turning the mute switch on and off. A loud transient accompanies this. Any recommendations for repair? I've had a couple of local techs look at it and cannot find what's wrong.

 

Is it random? Or does it occur during louder music (especially bass sounds)? Can't really diagnose it in a message, but it could very well be a power supply problem. My Hafler DH-101 had a problem where the LED on the front panel would light only about halfway, and the sound would be distorted...punching the power button a couple of times would sometimes pop the sound back in. Turns out the power supply capacitors were bad. 10 minutes to pop the covers, remove the bad caps and put in new ones, and all is well again.

Could also be a cold solder joint somewhere, or a bad switch. The fact that it's happening in both channels, though, makes me think of the power supply since it feeds power to both channels, whereas an audio circuitry problem would possibly affect only one channel.

 

Rudy:

Rudy: the problem is intermittent...doesn't seem to have anything to do with volume...but I'll gladly consider your suggestions....thanks!
Brad

 

I think Rudy is on to something, as far as a cap going bad somewhere...maybe not in the power supply, but...

Now, finding out WHICH ONE...that is another question...

best of luck,

 

What are you using for a power amp?
I had an Apt Holman for many years. I had it repaired once (just after the warranty had expired of course). IIRC the symptoms were similar and it was voltage regulator but I can't be quite sure.
Also had the Apt 1 power amp. The sound would fuzz in and out with a crackling noise. I discovered that fiddling with the bridging button on the back of the amp would solve it (dirty push button, I guess). I had always assumed it was the preamp making the noise.