This thing has reasonable gain, 20dB or x10, I've boosted the inputs with 80k series and it works for my needs (1.3 or 2.3dB gain). I suspect that many of the "failed" boards here could be due to the PAM8304 getting too much input to boost (0.5V would transfer it to the 5V rail). Try adding 100K potentiometers on the board before experimenting and make sure you start with a 100K series resistor and work your way down.
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