I just got a used Crate 400 watt amp, from a pawn shop. Well, when I played it at the shop, I was playing it down low, and It sounded great. Well after I got it for christmas I truned it up half way and It has a bad sound that I just can't explain. But it is very bad, like a sound like it's to much for the amp. Even though may tuner is broke, its not that, because no matter what it is tuned to it still is bad. If it helps I have a Peavey forum 4. I hope you guys can help me out here.