Hey - I am using this unit in my car and plugging into the stereo via a speaker cable. All works fine and sounds great, but then you plug it into usb charger and there is a lot of interference noise coming through.
I hae tried various difference charges and even little stand alone portable chargers to see if the cable/charging unit was causing this but it is happening with everything.
I have changed usb cables as well.
If i plug in my ipod via the same connector it is fine.