Thank you. I will run all the different possibilities. That last paragraph might be a little out of my league, but I'm sure I can find someone who can help me understand what you said there if it comes to that. You give me hope that this might be quite fixable.

Thanks, that's great info! I'll put my mind to it.

Ok, so I ran my guitar through another pre-amp and into the effects return and it sounds the same, so I guess that means it's the power amp circuit?

Any ideas on whether or not it's worth trying to chase this down on a relatively cheap amp?

Thanks, there is an effects loop section and I'll try that. Can I assume then, that if it still sounds crappy that it's in the preamp portion then?

Someone just gave me a Behringer ACX900. It was free...for a reason.

It has very low, distorted output. This amp has two channels and the problem seems to be in both channels. All of the bells and whistles seem to be working (EQ, effects, etc).

Is this a preamp problem? Is there an easy way to isolate the problem?

Thanks!