This is a switchable supply for AKG C12A and C12 microphones. The C12A I have uses a 7586 tube, which specs at a filament current of 135ma at 6.3volts. The C12A schematic and the Heizspannung switch show 5v to the filament pin. What value of load resistor(s) should I use? I don't have a schematic of this supply.