I know this topic has been posted before, but I am looking for any new ideas that may be out there.
I installed a Kenwood HU, and two MTX amps (4 channel for the fronts and rears, and sum out to the 2nd amp that drives the sub), with Infinity Reference series speakers (6 1/2" and tweeter with crossover in front, 6"x9" Triaxles in the rear, 10" sub). After the install, I noticed that I had an engine "whine" or alternator noise over the speakers (front and rear). The noise is constant, and does not change when the volume is turned up, but does rev with the engine.
I have tried the following:
-New RCA cables (supposed to be good ones, called Tsunami).
-Re-routed RCA cables to make sure they were run seperate from power.
-Cleaned ground (to bare metal) and grounded within 18" of amp(s).
-Checked ground to HU to ensure good ground.
-Ran a ground directly from the vehicle battery to the ground on the HU and the amps, no change.
-Disconneected the front channels, still had noise in the rear and visa versa.
-Ground loop isolators (the stereo place in town let me try them, but they did not make a difference).
I was pretty anal about the install too. ALL connections were crimped AND soldered. All wires were wrapped in electical tape and run through wire loom (the black plastic fexible stuff). I am kind of at my wits end here.
The only thing I noticed that made a difference was if I put a wire from a known good ground to the ground on the RCA plugs. This seemed to help eliminate the noise.
I am wondering if I can put a permanent wire from ground to the ground (or NEG) on the RCA jacks. Does anyone know if this will harm any of the equipment? Any thoughts are GREATLY appreciated. The stereo place wants $65 per hour to isolate the problem and they said it can take 6 hours (yikes).