Instead, this design relies on a dual OPA1642 ... drive a balanced audio connection. The circuit is designed to fit inside a common BM700 or BM800 microphone body, and the PCB can be ordered ...

Speakers and microphones are physically similar ... It’s built around a dual coil 6.5 inch subwoofer. The passive circuit design allows the coils in the speaker to be configured for differing ...

This is a low cost design, of a amplifier with a electret microphone capsule for the ADC of a 3.3V micro ... "jelly bean" 2 OpAmp's integrated circuit. The final schematic was drawn by my daughter, in ...