I have the Bose setup. I'm wondering if it's been there all the time and I never noticed it before (I was in the car with the radio and all power off; to hear it with the doors open and any ambient noise you have to have your ear right up against the speaker).

I'm pretty sure there's no radio damage either; it's not like I messed with the radio power or spliced into the radio harness anywhere.

With the radio on and iPod hooked up I notice some of the typical noise and hiss associated with that setup. Turning up the sound turns the hiss up too. However, the hiss with power off is not affected by the volume knob.