Okay, I tried to hook an extra amp to my system to test my sub woofer box. I have my small 4 channel amp connected for a while and everything seemed fine. I hooked my second amp to my system to test the woofer. Suddenly the 4 channel amp seems to be getting input from the sub channel and the front and rear channel. If I leave the subwoofer out terminals disconnected the 4 channel amp sound is muted, if I plug in either the RCA or the ground loop isolator to the sub out RCA of the deck, the sound gest better, and if I turn on the sub out on the deck I get bass coming to the 4 channel amp but not the sub woofer amp. And the sub amp is currently disconnected I was getting bad alternator whine with both sub amps I was testing. I tried grounding the sub RCA because they came with a ground wire, and I tried the ground loop isolator and was still getting the whine. Help? Could the deck be faulty?