So I have a Bluetooth (tried two different ones actually) AUX receiver plugged in and obviously it's right next to the 12V charger which has a USB adapter in it. When doing this I get a lot of audio interference. When I plug the BT adapter into a portable USB battery the interference is obviously gone. I have tried wrapping the USB & Audi cable in ferite cores but no joy, same noise persists. Does anyone have any good suggestions on how to avoid this problem ? Thanks
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