Re: Varible Speed Tape Drive System
Yes it does drive a power amplifier using ECC83 as voltage amplifier and phase splitter driving a pair of 807s with 450 volts on the anodes.
The output transformer is a 350-0-350 volt power transformer used in reverse, so you get 230 volts out of primary.
The only other thing is 0.25uF capacitor across the whole of the secondary winding - used to adjust so you get maximum output voltage.
But I do not need to build the power amplifier now as I just purchased a Vortexion Super 50 amplifier which has a 250R output tap which gives you the same thing.
Additionally I have a couple Ampex 375 the American version for driving an Ampex 300 or 350 or 400 usually the former. Which additionally uses 807s putting out 75 watts (American) probably more like 50 watts same as Vortexion, the Americans had a different way of measuring maximum output.
Incidentally I am looking for the Circuit diagram for the Vortexion Super 50 using 6Q7Gs and 6J5s, I have the circuit for the later 1955 version which is mark 2, the Mark 1 version was in production from about 1944, the Mark 3 version came out in 1959, yep I have the schematic for that as well but output tubes were changed to EL34s.
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