Hello all. Dealing with a little bit of an alternator whine issue on my 2007 Porsche Cayman. I'm running a Sony xav-ax5000 head unit rca out to a Zapco DSP Z8 which feeds a JL Audio XD800/8. I'm getting a persistent alternator whine due most likely to the fact that the RCAs between head unit and DSP must pass very close to the main charging cable for the battery. I've upgraded the RCA cables to shielded ones, checked grounds, reduced amplifier gain as much as possible, etc, but it's not cooperating so far.
Any ideas on how to best deal with this? A balanced line driver crossed my mind, but I don't know what options are out there these days.