Ron,

Thanks so much for pointing me in the right direction here! I have never heard of the sharpie trick before. I’m going to file that one away and use it for years to come. When I get home this weekend, I’ll sort this thing out.

Much obliged,

David

Forgive the clueless response, but when you say “the end of a Sharpie” do you mean the felt part where the ink comes out or the other end made of plastic? This is a new thing to me, and I’m sorry to bother.

Thanks!

Dave

Okay, sorry it’s taken so long.

Here’s the deal. I finally got the sound file, and it’s 2.2 mb, however, I can’t seem to attach any file larger than 75 kb. That’s bit small for an audio file. I can e-mail this.

When you get it, you’ll hear the guitar plugged in through the unit with the DMM on but not engaged. Then, you hear it on. At about 35 seconds into it, you’ll hear what happens if I gently tap the enclosure. That’s when it all goes south. You’ll hear all kinds of terrible noises. If I tap around the overload light and turn some knobs in arbitrary directions, the feedback noise and overload will stop. At which point, I may or may not be able to continue playing with out this noise. It varies. With some patience, I can get the unit to sound right and not make the feedback, but if I tap it again, it’s over.

So, I’ve checked the solder joints, and everything seems kosher. I’m stumped at this point. Could one of the op-amps have mailed it in? Or, does this have to do with grounding like I first suspected?

Thanks,

Dave