I have a Peavey Classic 30, and lately, the sound of the guitar occasionally becomes much quieter, then back to normal a few seconds later. Is this a sign that my tubes need to be replaced? Or, is this a problem with my cable or guitar? Would it be a good idea to tighten the bolts where the cord connects to my guitar and amp?
Pretty sure the tubes need to be replaced
Check the wires anyway, they can break inside with no real evidence they have on the outside.