48V Phantom Feed Supply for Microphones Introduction. For reasons that I find somewhat puzzling, there are very few decent 48V phantom power supply schematics available on the Net. Those that I have seen are either very crude, or require the use of a special transformer that (naturally) is all but unobtainable (or both). 48V Phantom (Microphone) Power Supply Circuit Diagram 48V Phantom Power Supply Circuit Diagram Its secondary feeds a voltage doubling rectifier formed by diodes D1 and D2 and capacitors C3 and C4. Capacitors C1 and C2 suppress the switching noise produced by the rectifier diodes.