There are six PCBs in the 312 mic preamp module:
- Main PCB, which hosts the main preamp circuits. Voltage regulator section has designator with "p" suffixes.
- Front cotrols PCB, which hosts the switches and gain resistors.
- FET DI PCB.
- Output trim PCB that hosts 600R t-pad.
- Discrete op-amp PCB.
- Gain potentiometer PCB - optional, for those who prefer to have a gain pot instead of a switch.
We can move on to the Front controls