11-17-2025, 08:44 PM
Hi Arran,
Yes, radios were made for various "zones" away from the large stations. There were the TRFs that you mentioned, 4 tube superhets with no IF amp tube but with an IF transformer for the city (no gain but the selectivity of a Superhet, the typical "AA5", consisting of convertor, IF, Detector / 1st AF, Output and Rectifier, popular in our area, and for fringe areas, a 6 Tube set, with similar layout to the AA5 but with an RF stage, usually tuned. Some of these sets had a 3 ganged tuning capacitor, tuning the oscillator, convertor and RF amp, others having only a 2 ganged cap0, tuning the oscillator and either the convertor or more often, the RF amp.
I have 2 "lunch box radios, one a GE model BX, the other an RCA R17-M. Both look the same and have the same circuit (RF Amp, Biased Detector, Output and Rectifier), which is not surprising because both were made by RCA in 1934. All tubes were 6V filaments, so much wattage dissipated, either by the ceramic resistor (the RCA) or the curtain burner "Cordohm" power cord (the GE). Both used a 37 (6V filament version of the 27) as a rectifier with the grid tied to the plate. The Emerson 25 used the exact same circuit and almost the exact chassis down to the '38 output tube mounted below the surface of the chassis, just like the RCA and GE. If one looks at the schematics from N/A, the the Emerson diagram is typical Emerson, the RCA and GE are typical RCA, but the parts values and circuits are exactly the same.
Yes, radios were made for various "zones" away from the large stations. There were the TRFs that you mentioned, 4 tube superhets with no IF amp tube but with an IF transformer for the city (no gain but the selectivity of a Superhet, the typical "AA5", consisting of convertor, IF, Detector / 1st AF, Output and Rectifier, popular in our area, and for fringe areas, a 6 Tube set, with similar layout to the AA5 but with an RF stage, usually tuned. Some of these sets had a 3 ganged tuning capacitor, tuning the oscillator, convertor and RF amp, others having only a 2 ganged cap0, tuning the oscillator and either the convertor or more often, the RF amp.
I have 2 "lunch box radios, one a GE model BX, the other an RCA R17-M. Both look the same and have the same circuit (RF Amp, Biased Detector, Output and Rectifier), which is not surprising because both were made by RCA in 1934. All tubes were 6V filaments, so much wattage dissipated, either by the ceramic resistor (the RCA) or the curtain burner "Cordohm" power cord (the GE). Both used a 37 (6V filament version of the 27) as a rectifier with the grid tied to the plate. The Emerson 25 used the exact same circuit and almost the exact chassis down to the '38 output tube mounted below the surface of the chassis, just like the RCA and GE. If one looks at the schematics from N/A, the the Emerson diagram is typical Emerson, the RCA and GE are typical RCA, but the parts values and circuits are exactly the same.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
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Best Regards,
MrFixr55
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