[Jeffhs]

Originally Posted by Bob E.

Some areas of the US were 50 Hz until the late 40's, and some rural areas (and places with Edison power) were DC early on. I have a Magnavox "Concerto" phono from 1936 that is listed as 117 Volts, AC or DC. It has five tubes (two 25L6, two 25Z5 and one 6C5 with the heaters in a series string...no transformer so it doesn't care about the incoming power frequency! I also have a Mills jukebox from the same year, and it also has the ability to run on DC. It uses 2A3's for outputs, though, and I haven't looked the schematic over yet to see how it does the job on DC. I think there are some connection re-configurations you have to make.

--Bob

A phonograph that operates on AC or DC? I can see the amplifier running equally well on either source since series tube strings will operate on either type of power, but I'd think DC power would burn out a synchronous phonograph motor in no time flat, as soon as the motor was switched on.