Descripción
The five octal based tubes (valves) used in the 1948 AWA Radiola 525-M AM broadcast receiver are :
6J8G, 6SK7GT, 6SQ7GT, 6V6GT, and the rectifier tube 6X5GT.
Note that the ''6'' indicates that the tube uses a 6 Volt filament. The filaments [heating elements] are what initiate the flow of electrons through the tube, from cathode to anode. The flow of electrons is controlled by ''grids'' situated between the cathode and the anode.
The mixer/oscillator converter tube 6J8G is the only tube with a ''top cap'' (Grid connection). The other four tubes are glass tubular (GT) with no top cap connector.
Footnote: Would love to have a working AVO valve tester just to check the gain and mutual conductance of these tubes, but the cost of a working AVO tester is way above my limited budget !
Update: I have purchased ANOTHER AWA 525-M radio. This one has a ''bakelite brown'' cabinet and is in good working condition. I'll show it on video when I receive it.
NOTE -- My thoughts:
In a remote area with almost zero electrical interference, or back in the 1950's or 1960's when electrical interference was not an issue, this valve radio would have been an ideal receiver with its 5 inch speaker, but now in the 2020's there's so much bloody interference everywhere, a 1948 valve radio has become not much more than a ''collector's item' !
To listen to this radio operating : You can see and hear the radio operating in this video here https://www.youtube.com/watch?v=f4CpIXRQBYw&t=3s