I know nothing about amps, cabs, heads, etc. I just get a big enough combo and play it until it dies. Thing is, I don't want this one to die. I have an SWR Workingman's 15. I turned it on the other day and got a low humming noise. It got louder. I turned it off. I turned it back on a few minutes later, and it had evolved into an ungodly shrieking noise. It definitely was not flourescent light interference. It was a loud, ground shaking squeal that'd shake the fillings out of your head. Ever hear of anything like this? I got it used two years ago. The way I see it, I'm S.O.L. Are these expensive fixes? Is it worth fixing? BTW, I've always been fairly happy with it. I'd like to try something new, but I can't sink the necessary cash into what I'd really want. Advice?