Want to track down a schematic for an unknown pre-40s RCA Victor BC/SW wooden table top radio. Has the following tube complement:
25Z5, 43, 75, 6D6, an unknown tube plus a metal tube which has some sort of heater in it. Can anyone give me a model number?

: Want to track down a schematic for an unknown pre-40s RCA Victor BC/SW wooden table top radio. Has the following tube complement:
: 25Z5, 43, 75, 6D6, an unknown tube plus a metal tube which has some sort of heater in it. Can anyone give me a model number?

Hi Barry

RCA made a lot of radios around 1936-1937 that used those tubes. The tube you couldn't read is most likely 6A7. The metal one is called "ballast tube". Your radio tube filaments are wired in series with the AC line and a ballast tube acts as a resistor reducing the voltage.

Norm

: : Want to track down a schematic for an unknown pre-40s RCA Victor BC/SW wooden table top radio. Has the following tube complement:
: : 25Z5, 43, 75, 6D6, an unknown tube plus a metal tube which has some sort of heater in it. Can anyone give me a model number?

: Hi Barry

: RCA made a lot of radios around 1936-1937 that used those tubes. The tube you couldn't read is most likely 6A7. The metal one is called "ballast tube". Your radio tube filaments are wired in series with the AC line and a ballast tube acts as a resistor reducing the voltage.

: Norm

Hi Norm,

Thanks for your response. Are there any web sites that might have pictures of these radios or some information I can use to narrow down a search for a model #. Any ideas will be most appreciated.

Barry