This whole thread just hurts. So much money spent for a good experience that the user certainly isn't getting, from his perspective.

A number of people in various threads on too many forums to count, install stereos from trusted brands only to find out they've got grave design flaws. So much is designed by these companies and sent to China to produce. I don't know if these companies QC it afterwards, but it sure seems many don't.

Try grounding the negative lead of your RCA cables to the same ground your device is connected to. For the source, ground those leads at the same point the source unit's power is grounded. For the amp, ground them where the amp is grounded. Do it for the source first, check if the whine is reduced or gone. Do it for the amp, check if the whine is gone or reduced, and then try it for both at the same time and see if the whine is reduced further, or gone. If any of these steps you've taken temporarily works, make them permanent.

You can't build your own radio, so bandaid solutions may be all you can commit to. If it gives you the sound you desire, make it permanent. I've got an Xtron Android head unit in my E53 and the whine was initially awful until I committed to grounding the negative of the RCA output leads to the same ground as the head unit. The whine is only noticeable now if there's no music playing and I'm at a stop allowing me to rev the engine.

Also, I don't remember reading it in this thread, but if you used the "stock" ground for your head unit, I'd suggest making your own.

__________________
- 2011 BMW X5 x35i
- 2005 BMW X5 4.4i
- 2005 BMW X5 3.0i
- 2004 BMW X5 4.4i