[Arran]

32 vdc was what some sets used, the farm lighting plants used to use 8 volt lead acid batteries for storage, in a series-parallel arrangement, 32 volts was also the standard for electric light on trains. I have a 32 volt Phonola set that seems to be a licensed copy of a Wells Gardner circuit, I also have a 6 volt Stewart Warner vibrator radio that uses 2 volt battery tubes in series. As I understand it G.M/Delco was a big proponent of 32 volt sets in the U.S since they manufactured the lighting plants, I'm not sure what the Winchargers put out but I think some may have been 32 vdc, as well as 6 volts. A lot of farm battery sets were converted to run the tube filaments from 6 volt car batteries by using a rheostat to drop the voltage, I think the reason was so it could be adjusted as the charge went down, some even had a built in volt meter for this purpose. I have found croc clips on the "A" leads of many battery sets with the 2 volt tubes, so wet cells were obviously the preferred method of obtaining filament voltage. The Air Cells were 3 volts, most of my 2 volt sets have a built in dropping resistor, with a terminal panel for shorting out the resistor for 2 volt operation.
Regards
Arran