So I've been gutting the car, and working on my new stereo install.

I blew my Xtant monoblock sub amp, and then somehow i developed a ground loop. I couldn't get rid of it.

Nothing seemed to work. I went so far as to totally redo my headunit harness, and all of the wiring. New power wire, new RCA's EVERYTHING.

So tonight I tried something I saw on here once before. My new RCA's came with a "drain wire". I connected one end to my headunit, and the other end to metal part of one of the RCA cables at my amp.

My head unit is a pioneer p80mp, and I just installed my Soundstream LW2.240. If anyone is familiar with this headunit, it has a replaceable set of rca's that plug into the back. I am wondering if the headunit is bad, or if it might be the RCA's? Anyone else ever had this problem?

Your help is greatly appreciated, because the headunit is about 10 months old and it shouldn't be having these problems.

Oh, and by the way.... The noise was the whining that goes up in pitch as the engine revs up. Only there with the amp connected to the headunit, and not there in the speakers that are only connected to the speaker outputs...... Only the speakers connected through a preout and amp....

Thanks again.