Car Audio help!
 

I just recently installed an Aux input into my Blaupunkt Toronto unit. This works fine and no extraneous noises. When I use the car docking unit for the Samsung Helix, I immediately get a very, very high pitched whine. For the power to this, I installed an extra 12 volt lighter socket. The ground for this goes to the chassis and is pretty solid. The power is coming from an extra power line from the fuse box that use to power the old amplifier. Do I need to change the source or is there a isolator that would be useful. The noise is not related to engine rpms also. It comes on as soon as I power it up. Once again, the aux input works fine if it is directly plugged into the source. Something about the power to the car unit is at fault. Thanks.

My bet is that you have some sort of ground loop going on there. This happens sometimes when two or more devices are connected to a common ground through different paths...

There is a lot of information on ground loops, and different suggestions for how to fix the problem. If i were in your shoes I would skip the research, and try changing where you connect the ground wire.

That's my thinking. Thanks.