I am not sure if this is a design flaw inherent in the Gigabeat F or my unit has a defect. In my car, I have a mini-USB charger hooked up to my lighter. My Gigabeat F is attached to my car stereo via the AUX input. When I charge the Gigabeat and play music at the same time, a high frequency noise can be heard which is very irritating. I noticed that the loudness of the sound was correlated to how much I was pushing the gas pedal (pushing the gas pedal=louder noise). Anybody got an idea how to fix this?