08-10-2013, 07:35 AM
I think that the 199s are 3 volts, the 30s are 2 volts, but the 201As are 5 volts at .25 amps each. I would save the 199s for an RCA set that uses them but the types 30s make perfect sense to use as a 201A substitute, however the filament current and of course the voltage is different so the original rheostat/volume control setup in a 201A equipped set won't work.
Regards
Arran
Regards
Arran