Introduction to microphone board:The microphone reverberation chip adopts PT2399, and the microphone amplification and front-end amplification respectively use a fever level operational amplifier OP275. The volume of the two microphones on the microphone board can be independently controlled. Dynamic microphones and electret microphones can be versatile. The board has MIC-1 volume, MIC-2 volume, reverb frequency, reverb, and external audio volume adjustment.Working voltage: AC: 6V-17V or DC: 12V-24VBoard size: 100m * 50mmPotentiometer spacing (fixed version of potentiometer): 22mm