I have MP3 module, control via I2C, dedicated for RPi or Arduino usage. Such module has symmetrical output (probably on-chip D class amplifier) with OUT- and OUT+ pins. None connected to GND. Output is dedicated for high impedance loudspeaker (over 30 Ohm). But I want to connect it to input of the amplifier with SIGNAL and GND pins. How can I do it in the most simple way?