If I turn the power output of the high frequency, or the main power output of the amp up, more than 1 (out of 10 approx) I get a very high pitched (constant) feedback through the door speakers. It does not fluctuate with the revs of the engine, so alternator interference is out. It is a constant pitch and volume regardless of music volume. I do not hear it with the stereo off. It only shows up with the stereo turned on, even with zero volume.
Dunno what the issue is. Could it be the power cable is too close to other wires?
Dunno what the issue is. Could it be the power cable is too close to other wires?