Ground Problem - Noise

I have a 2-amp setup in my ride. 4-gauge power from the battery runs to a 1 fd capacitor, then to a distribution block, splits into two 8-gauge to each amp. Both amps are grounded, as well as the capacitor. The ground locations have been stripped of paint, e.t.c. But I still have noise in the system when the car is running. I was wondering if anybody thats ran into this problem could help me out with some troubleshooting ideas. Thanks a lot.

How did you run your signal (rca, speaker wires) and your power wires thru the car? Are they on opposite sides of the car?

what ^ said. Gotta wire it right. That and make sure that it is a good clean ground.

All power and ground cables run through the middle of the car, and all rca, and speaker cables run on right or left side. Ground location is clean, been sandpapered till there was nothin but metal shinin through. Still got noise.

How long are your ground wires? (The ones to the cap and amps?)

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What?

check the gains on your amps, if they are wide open there is a greater liklihood that you will experience noise problems - Also could be a sign of a weak alternator

try disconnecting your alternator before you start the car , see if the noise is still there , if it is not you may have a bad bridge rectifier in the alternator 

All lengths for the ground wires are around or under 8 inches. I'll try disconnecting the alternator before I start the car and see what happens. A friend of mine has the same make, model, and year Galant and his alternator just went bad a while ago, so that may be the problem. Thanks you guys, and I'll keep ya posted.