Here is a little background about my system...Eclipse AV5501? with brain going to a Pioneer grapichal EQ headunit -> amps -> speakers. It was proffessionally installed a few years ago and has always had a whine with the engine revs plus a little background noise. I recently bought the car from a family member. I took apart the dash and middle console today (2002 tahoe) and played with the wires. If I unplug the rear speakers RCA from the EQ, there is absolutely zero noise. If I bypass the EQ and go straight from the brain to the amps...its the same thing. No noise with the rear RCA's unplugged. There is noise with them plugged in.
I also notice there was a little RCA noise filter plugged in between the brain front RCA and the EQ. There were two little brown wires sticking out. Should they be plugged in to anything? I'm sure all of this is related to a bad ground somewhere. Any ideas?
You can try connecting all rca outer conductors directly to ground at both ends. Also, run jumper wires from all the grounds of your different pieces of equipment. That way they're all the same.
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My ex once told me I have a perfect face for radio.