• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Anyone tried using the switching power supply module for tube amp

I think 200KHz for DH tubes is fine. You could wind something around a ferrite toroid with separate secondaries for each DH tube. The CT could then go to the cathode resistor. Does not have to be mains invertor just a simple balanced forward convertor.