06-19-2015, 07:24 PM
Posted this on ARF too, where I got the NIB 237s, but thought I might get a different answer here since I referenced the use of the tube in a Philco radio:
The 6 NIB RCA 237s I just bought, and very happy with, from our want ads:
http://www.antiqueradios.com/forums/view...5&t=278649
Well all of the boxes and the very nice included spec sheet say that they need DC on the filaments. I had always thought of a 37 as a 6.3V 27 which is fine on 2.5V of AC. I looked in the early RCA tube manual and sure enough, specs out DC filament. So the use of 5 or 6 Philco labeled "37s" in my 115X are wrong (also globes)? Or did other manufactures build them with different heater/cathode specs? Or did they change the tube OR the spec sometime along the way. OR did Philco just ignore the spec?
The 6 NIB RCA 237s I just bought, and very happy with, from our want ads:
http://www.antiqueradios.com/forums/view...5&t=278649
Well all of the boxes and the very nice included spec sheet say that they need DC on the filaments. I had always thought of a 37 as a 6.3V 27 which is fine on 2.5V of AC. I looked in the early RCA tube manual and sure enough, specs out DC filament. So the use of 5 or 6 Philco labeled "37s" in my 115X are wrong (also globes)? Or did other manufactures build them with different heater/cathode specs? Or did they change the tube OR the spec sometime along the way. OR did Philco just ignore the spec?
