Reduced gain with ground loop isolation with car aux head unit
Now I'm stuck with a loud noisy system, or a clean radio that's way too soft. As I understand it, a ground loop is caused by kind of resonance or improper grounding.


That's the reason why you can use the built in differential amp in this IC, the pins are 2, 3, 34 and 35. Connect your L and R signal to the cap of pin 2 and 35, Gnd to cap of pin 3 and 34. These pins seems to connect to somewhere, so be careful when you decided to cut trace to isolate them.

When you plug in your 3.5mm plug and charge at the same time, you should not hear any hum. However do note it needs to be grounded to work and currently it's grounded to the USB Gnd pin. I don't guarantee it to work if you decide not to charge and play. There would be a switch to use the differential amp, that you have to find out how to enable it.