Radio noise.. need help

[TinyGiant]

if i have my ipod connected just to the HU its fine.. no noise..


when i have the ipod plugged into both the audio and the 12v power supply i get a high whine noise..

i also noticed when screwing the screw in for the HU mounting bracket that when i touch the car to the bracket i get a buzz..

sounds to me like there is a ground loop somewhere?


i was getting lots of noise from the radio antenna.. and i bought a noise filter for that and now the antenna noise is gone .. but now i have 12v adapter noise.. lol


any ideas?


think its just a bad HU?

i tried taking the power from the sub amp to see if it was the ground from that giving me issues and its not..

any help will be appreciated.