Morning bump.

I connected the cable between a pair of RCA pre-outs and the HU chassis and it seems to have stopped 80% of the hum.

Adding my noise isolator reduced another 17% of the hum so now it's almost dead silent.

Am I losing any sound quality with the isolator? Would soldering the ends actually help reduce the noise even more?

 

Yes in line noise isolators on the rca cable reduce the audible spectrum. If the frequency that is "whining" overlays a frequency that you are hearing, if one is eliminated, so is the other.

I would sell the deck to someone who may not need the preouts and find a new one.

 

Definitely it will reduce some sound quality... i refer MR2NR suggestion

 

wait I have a similar issue. I heard a pop when I connected my remote wire, now I can't get any sound for the new install of 2 amps and 4 speakers. I thought I fried the HU but I have a new HU and still no sound. The error mssg on the head unit when I adjust volume **** says AMP GRND