The PS2 aluminium tube microphone power supply provides filament and plate voltage for vacuum tube (Valve) single diaphragm condenser microphone.

7-pin XLR connector pinout

pin1 - Plate voltage 200V

pin2 - Filament voltage 6.3V

pin3 - N/A

pin4 - COM connected to the pin7 inside the microphone

pin5 - OUT-

pin6 - OUT+

pin7 - Shield/GND