• 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.

12 volt power supply for tube amps

Consider an old solid state 12 volt power supply designed for some of the older tube ham radio transceivers. Virtually no one runs these radios mobile any more, so a supply should be dirt cheap. Sometimes these even show up as NOS for about dirt cheap.

Drake DC-3, DC-4, Collins MP-1; there are likely many others out there.

Use it as-is, or gut it for the parts. If I were to build a mobile tube amp, this would be my starting point for power.

this is my 300b car amplifier
out put is 8 Watt + 8 watt

power supply is 12 volt to 110 volt 60 or 50 Hz


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Why not just buy a regular DC-to-AC power inverter? These things are dirt cheap these days. That way you just plug a home amp into the AC power. The output is typically a distorted, noisy waveform, so you'd want to make sure you've got line filtering in between it and the amp, but you'd have to do this for any switching option anyway.

Cheap power inverters

The idea of 300B filaments jangling along with road bumps and vibration gives me the willies, but I guess you could vibration-isolate the chassis as much as possible.