I'm planning on buying a multimeter to use mainly on guitar and amp electronics, but I have very little idea of exactly how to put it to use
I'd been having issues with my Randall RH150 (crackling, crunching the cleans and cleaning the distortion, sound fading and disappearing etc), at first I thought it might be the input socket but I changed it and the problem persists. Could it be the preamp tube?
How old are the tubes? Replacing the preamp tubes could fix the problem. But more info on the symptoms is needed.
A multimeter is useless without the skills to use it, and you can seriously injure yourself if you start poking around in an amp without a clue.