I own a Peavey Bandit 112 amp, it's probably about 6 years old or so. I've noticed recently, when I turn it on, it gives a ton of feedback, to where I have to turn it up about half way to hear my guitar over it, and the distortion is all screwed up. The low end is completely gone and the treble is overwhelming when this happens.

It doesn't do this all the time, other times it sounds perfect. And I noticed if I shut it off, then give it a "little tap" with my foot on the top, it will either fix itself or get worse. Anyone know what this could be? Like, maybe a loose wire or something?...I honestly don't know **** about amps.

Anyone have any suggestions on how to fix this, or maybe a new amp to buy, because this one is ancient, I nicknamed it Keith Richards because it acts like it wants to die, but I don't think it ever will.
"Ignorance runs rampant through this virus we call life, dead one day, alive the next, never breaking a stride. As I take it all in and realize, nothing we do can stop it, I release the hatred from my eyes, only to feel it within."
it sounds like the jack is loose on the amp this is my problem with my ole one i pulled the lead vertical and around the amp tight for temp fix, or u just take it apart and tighten the damn thing lol