the other day i was listening to my music and allof a sudden my sub cut out, i thought maybe the ground wire had come undone so i checked it out but it was fine..so i unplugged the line input and plugged it back in then it worked for liek two seconds and stopped working again all the other connections are fine..and the amp power light is on so it looks like it working? so im wondering if my amp is messed up or my sub is going?