Are these available if you're using speaker-level inputs?
I know, I know, but it's just a temp fix.

 

http://www.crutchfield.com/cgi-bin/S...=1&cc=01&avf=Y

PAC COF-2

Here's a little thing I found. Dunno it it will help any though

 

I've never seen that before. I may have to try that after all the grounds are taken care of.

 

Usually high level inputs never have noise. Try running a 10ga ground from your radio to the amp in question. Also turn the amp down. With high level inputs there sould be no reason for gain to be over even half. If you are running more than one amp make sure the grounds are either at the same point or you connect them together w/10ga wire. Try fixing the grounds before you buy anything. I have seen these ground loop isolators make the noise worse and also some systems have lost bass because of them.

 

Ground loop isolators work on line level signals not speaker level signals.

 

So, I should run the ground wire all the way form the head unit to the speaker-level inputs? I had the amps tap into the stock ground wire the leads into the stock Delphi amp (which isn't used anymore). Then, because of all the noise, I took the grounds on the speaker-level inputs off of that tap, and grounded them directly to were the cap grounds. All of the amps are grounded at the - terminal on the cap with 8ga wire, and then the cap is grounded to the fender well with a 4ga fround wire. My next step was to ground the head unit at the transmission tunnel.