OK, so heres the scenario. Me and a friend redid my system this past week and I now have alternator noise. I have done everything except running the source unit power directly to the battery, grounding the RCA's, and a power line noise filter. The amplifier is a brand new powerbass ASA 400.4. Note that the amps were in the trunk before and all the wires were ran together per the installer that put them in and I had no noise at that time, but that was the old amp that got 2 channels burnt up. We had to redo all the wiring due to a new box and amp rack and we got alternator noise for free. Any input would be greatly appreciated!