frustrated with audio whine with Sirius install

[ssnake3]

hey all,

Im new to the forum, and have only had by G35x for about 3 months now. so far I am really happy with the car, but I am struggling with the install of my aftermarket Sirius tuner. I have the tuner wired into the AUX input (non Bose stereo), and the sound is fine (no whine) as long as I dont have the the power to the tuner connected to the cars 12V source. however, as soon as I plug the unit into 12V from the car there is a noticable whine, similar to alternator noise coming through the speakers when listening. I have tried different grounds, even running a wire directly to the negative post on the battery, and yesterday I tried running a power wire direclty to the positive post on the battery. Nothing seems to impact the noise, do any of you have any ideas how to stop the noise? I did not have this problem with the same tuner installed with the same power adapter in my 04 F150.