04-01-2017, 01:46 AM
If I'm right about the power supply in this set they may be connecting the battery tube filaments, in series with the cathode of the amplifier section of the 70L7 tube, it probably also has a dropping resistor in series with the heater of the 70L7 tube. I have one or two radios that work this way, it gives you much more audio power then the 3Q5 tube would.
Regards
Arran
Regards
Arran