mwc,
First off, is there a reason you feel the need to touch the amp after it is turned on?
I suppose if you feel this need to touch your amp during playback then certainly you have a large problem.
However, you are not alone.
I am borrowing a friend's Phillips vintage preamp right now and it has a similar problem. When i touch the mute button, i sometimes get a popping noise and my left speaker channel cuts out. The only way to reset this problem is to shutoff the amp (not the Philiips preamp) and then turn it back on again.
The buttons on the Phillips are a touch sensitive design, not something i would personally put on an electrical device of this nature.
Anyway, to cut the story short, it is an electrical problem with grounding. There is no way to fix this in my situation unless an addition is made to the inside of the amp itself (some type of unit that is similar to a power bar surge control).
