I purchased a used Nuemann nKma PSU a few years ago. I am now putting it into service with a KM264/AC701 I was able to adjust the plate voltage to 120V, but I need help with the heater voltage. Without the mic attached it is 5.2V. Will it be closer to the needed 4V when the mic is attached? I don't want to subject the mic to over voltage.
Do you have a schematic available? Can you talk me thru the heater voltage adjustment procedure?