zune car charger noise

I'm using a Zune in my 04 Toyota Sequoia OEM deck with a cig lighter charger and PIE Aux in. When the charger is plugged in I get a fairly loud hum/buzz out of the speakers when the music is quiet or paused. I don't believe the problem is in the PIE device because if I unplug the Zune from the lighter adapter the noise goes completely away. Last night I tried wiring the lighter charger directly to where the power goes into the radio (I read something about "ground loop") and that had no effect. I also plugged the lighter adapter into a separate power source from the car (one of those "jump start" batteries with a lighter socket) and the noise went away. This leads me to think it's not the lighter adapter but something between the four (adapter, zune, PIE, OEM deck) that is causing the issue. To try one last thing I changed the cable from the zune to the PIE and it also had no effect. I'm pretty sure the noise is coming from the zune because when you push buttons or the screen goes dark the noise changes. Thanks, RJay

noise is not coming from the Zune...its coming from the charging source.

aznboi3644 wrote: noise is not coming from the Zune...its coming from the charging source.

If I plug the charger into a 12vdc source outside of the car the noise goes away?? I guess that leads to believe the noise may be coming from the 12vdc going into the charger when in the car. Would a power line filter help then? Also, when the noise occurs if I unplug the cable that leads to the PIE aux in and plug in my headphones no noise. If the noise is coming from the power wouldn't I hear it in the headphones also?

I picked up a SNI-1 from Pac Audio http://pac-audio.com/products/productsCatagory.asp?mmSearch=Noise%20Filters last night for $20.00 and it has done the trick. Because this is a directional isolator I had to buy two male/male and two female/female RCA plugs to make it work. Noise completely gone and I don't notice any sound degradation, at least not enough to be a bother in a vehicle. Thanks for the help. RdJay

i am an idiot wrote: The only way to get rid of the noise is to use a ground loop isolator.

I am having a similar issue with my Sirius, since it is a 5 volt converter and I hate having light plugs show, I am gonna wire a hidden lighter receptacle to plug it into, would it help to put a filter on that or do I just need the ground loop isolator to run inline with the 3.5mm plug or RCA's