could be the way its wired, with alot of wiring causing sometype of electrical interferance, power wires should not be right next to speaker wires, check ur fuses, if there was a power surge then it could cause something to blow if something was short circuited after the fuses, the stuff u installed has nothign to do and is no where near ur amp so unless u bumped the power wire or upsetted a connection it shouldnt be related at all. hope that helps u some