I just bought this off of craigslist , guy told me it is messed up but works. I gave him ten bucks and didn't bother to try it out. Today I hooked it up to my Musicman cab and plugged it in . All kinds of scratchy noise. I mean a lot. I started turning the knobs back and forth . they started cleaning up. I plugged my Bass in , sound is coming out. Scratchy but there. I play with the knobs some more and all of the sudden , BOOM! A C note rattles all of my windows and walls. I pull the plug out of my bass. Then a hear a crack. Something has collided with the side of my house. I go to my front door and I see my neighbor outside. I ask him , " Did you just throw a rock at my house?" He yells , " Mother****er I can't ****ing sleep!" I said sorry , as I have many a time before and walked back inside. This piece of junk I bought has piqued my interest now. I know nothing about these amps. There is a row of circular metal housings on the back of this amp. the scratchy noise sounds like bad tubes. I am asking if maybe this solid state amp has a tube preamp setup and that is what is causing the scratching?