I picked up an old ESR amp around 1990, it was very loud, lots of distortion but noisey as in undesirable distortion not the good kind... its got a solid state peramp and tube power stage, (4 6l6 if I remember right) six 10's in a tall tweed cabinet. I think it needs an output transformer as I can only get a teeny little tinny sound from it now.... I havn't tried to troubleshoot it other than checking for bad connections and obvious stuff.