Installed the amp and the subs and head unit fine. before putting everything in place, decided to try it out in case we had any problems. the subs and amp work fine. problem is, theres no TREBLE! actually, theres no sound at all coming from front stage. also, the back of the head unit is getting real hot. my friend just bought it from a guy he found on craigslist. i would just think the problem is with the head unit, but i hooked another one up, and there was no treble with it either. I need help! any is appreciated!