Re: How do you figure out amp mods?
I'd say open it up and look around for internal pots that you can tweak with a small plastic-tipped screwdriver. Sometimes these are attached to EQ circuits to tailor the frequencies the front knobs affect, other times they're attached to gain circuits that the front knob affects.
And once in a while you find one that's attached to something that could cause your amp to fry if you turn it too far.
But WTH, it's only money.