Bonneville America Forums Forums Off Topic Discussion Forums Lounge Any electronic wizards amongst us?

An old install trick we used to use back in the late 80s early 90s when we encountered noise was to ground the outside of the RCA cable to the ground of the amp.
Easy to do... use a length of wire, attach one end to the ground connection at the amp and the other end to the outside of one of the RCA connections. If the noise goes away you find a way to make it permanent, if not your issue is magnetic interference and you'll need to separate the wires.