corroded inside or bad connection. even a monster amp fuse for 15 bucks was shit when i bought it.. but if that doesnt do it. then what you want to do is.. get one of your friends amps and just run your wires to his amp and see if you have the same problem. if not then you got a bad amp.. amp is probably telling you that it wants to die and be replace by something better and newwer.. my amp did the same thing.. i got pissed so i decided to start burning it.. (LITERALLY)
You know things are going to hell when : 1) the best golfer is black 2) the best rapper is white 3) the tallest basketball player is chinese 4) and germany doesnt want to go to war..