naku... minsan ganyan talaga ang mga cheap amps... try looking for a better ground reference...kiskisin mo nang mabuti ang pagkakapitan, until makita mo na yung bare metal lumabas... then tsaka mo na ilagay yung ground wire mo. in this way, kahit meron kang static sa system mo, sometimes doing this may solve that problem din.

an easier way to remedy your problem is buy yourself a better amp...