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I have a KKmoon TDA7492 bluetooth sound amplifier board with an AUX interface (https://www.amazon.co.uk/gp/product/B075QZ19VJ/ref=ask_ql_qh_dp_hza). The issue I have is that whenever I connect anything to the board through bluetooth, it produces a static sound on the right speaker specifically. I tried multiple speakers but it is always the right speaker (or whatever speaker is connected to the right connection of the board) that starts making a static sound. The interesting bit is whenever I connect any device through the aux interface, there's no static sound and it works perfectly.

This makes me think that there is a ground loop and the bluetooth chip isnt grounded (also suggested by a few other people too). If this is the case (please correct me if I'm wrong), the chip has 3 ground pins (pinout in picture) and I am unsure whether I can just connect a wire to any of the ground pins to the negative terminal or if there are any specifics.

Any help is appreciated.

Thanks beforehand!

Bluetooth chip pinout

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  • \$\begingroup\$ Do you hear a 577Hz tone? I think that is the Bluetooth packet rate. In any case, the tiny transistors on silicon are often excellent rectifiers of radio energy; if the internal bias currents are increased or decreased as your Bluetooth TX responds; you could be hearing re-transmit requests or simple ACKnowledge responses. In any case, 1 milliWatt across 50 ohms is a peak-peak level of 0.632 volts; by jamming that into any pin of any analog circuit, you will get rectification in the AC_nonlinearity of the ESD structures. \$\endgroup\$ – analogsystemsrf Feb 27 at 13:18

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