Whining sound when radio is on?

[Pocket Chant]

So, I have an aftermarket radio in my E30. I noticed the other night that there is a slight whine when it's on, and it increases with the RPM. (It's not the antenna either, but it sounds similar.) I figure it's a Ground, but just wondering if anyone would know which one in particular.

Thanks!

[randomtask37]

from what ive heard when the whine increases with RPMs it has something to do with the alternator. either it is going bad... or maybe the alternator ground is bad. I dont know for sure, but this is what ive heard.

[dwvw]

All alternators produce that sound, and the more output it has the more of that sound it will put out. Your first line of defence against it, is a good battery. The battery filters the noise best when it is in good shape. If your battery is more than 4 years old, replacing it is usually a good idea.

Do you have an amp in the car as well? Alternator whine is usually caused by a ground loop, which is a difference in potential between two or more grounds in the same chain of components.

[Pocket Chant]

Alright, so I think the problem is in the HU wiring. I went into the back and relocated the Amp ground, that didn't do anything, tried unplugging the RCAs on both ends, no good. Then when I pulled out the HU to get to the RCAs, the noise got louder. I fiddled around with the wiring going into it, and it made even more noise, then almost none. I'm tracking down the particular wire now.

[LJ851]

My car did the same, removed the factory amp and it went away.

[bigdaddy325ic]

Bad ground !!!!!!!!!!

So, I have an aftermarket radio in my E30. I noticed the other night that there is a slight whine when it's on, and it increases with the RPM. (It's not the antenna either, but it sounds similar.) I figure it's a Ground, but just wondering if anyone would know which one in particular.

Thanks!