09-09-2013, 09:27 PM
It looks like the model 52 just uses a simple shunt volume control in the antenna circuit, basically it controls gain by the wiper moving closer or further away from ground potential. It's the one in the model 50 that also controls cathode bias on one of the #24 tubes, the model 50 is a cheap TRF set, the model 52 is a superhet.
Regards
Arran
Regards
Arran