Quote:
It appears from the diagrams I have that the CD changer outputs balanced signals. I have a few things to try first (after power from Ibus)

The whine is coming from currents flowing through the shields in the RCA jacks.


I finally get the time to look to the noise issue, for the first part, I examined for well the original cd-changer: in the rear there's something that's look like a post-production add-on (where I-BUS connector & audio-linees connector are soldered); the circutary is a simple battery filter, and near the audio connector there's a passive band-pass circuit. One fact I got from this circuit is that negative audio output are common, then it's a balanced output non-GND relative (like all decent equipment out of there).

After checking this, I immediately installed an additional 3mm diamater direct wire from battery and the empeg/I-BUS interface and all the noise just disappeared (even with the engine turned on).

I'm veeeeeeeeeeeeeeery pleased of this, but now, to put another big smile on my face, I have to find a way to get a stereo balanced pre-output line from the headunit to add a subwoofer.