Home  Resources  References  Tubes  Forums  Links  Support 
Homebrew B Voltages
7/18/2004 10:35:05 PMJeff
Hi,
I'm working on a 3-tube regenerative homebrew. There were no tubes in it when I got it, but I'm assuming they're probably all 01A's. Whoever built the thing back in the 20's installed four binding posts for battery connections. One is marked "A+B-", the second "A-", the third "B+" and the fourth "Amp". If this thing uses 01A's, the A voltage would be 5-6 volts. I'm not sure what B voltage to apply to the B+ and "Amp" (which I'm guessing is a higher B voltage). There are two interstage audio transformers, the first being a 10:1, and the second a 3:1. I don't want to fry anything when I get ready to power this thing up. Would 22.5 and 90 work?

Thanks///Jeff

7/19/2004 12:46:47 AMNorm Leal
Hi Jeff

I would use as you suggest. 01A's need 5 volts for the filament. Usually these radios have a rheostat and were used with a 6 volt battery. Detector stages often used 22 1/2 volts. Amp at 90 volts is also reasonable.

You are lucky the audio interstage transformers are good. Often they are open in older radios.

Norm

:Hi,
:I'm working on a 3-tube regenerative homebrew. There were no tubes in it when I got it, but I'm assuming they're probably all 01A's. Whoever built the thing back in the 20's installed four binding posts for battery connections. One is marked "A+B-", the second "A-", the third "B+" and the fourth "Amp". If this thing uses 01A's, the A voltage would be 5-6 volts. I'm not sure what B voltage to apply to the B+ and "Amp" (which I'm guessing is a higher B voltage). There are two interstage audio transformers, the first being a 10:1, and the second a 3:1. I don't want to fry anything when I get ready to power this thing up. Would 22.5 and 90 work?
:
:Thanks///Jeff

7/21/2004 6:55:56 PMJeff
Norm,
Thanks again for your help.
Jeff

:Hi Jeff
:
: I would use as you suggest. 01A's need 5 volts for the filament. Usually these radios have a rheostat and were used with a 6 volt battery. Detector stages often used 22 1/2 volts. Amp at 90 volts is also reasonable.
:
: You are lucky the audio interstage transformers are good. Often they are open in older radios.
:
:Norm
:
: :Hi,
::I'm working on a 3-tube regenerative homebrew. There were no tubes in it when I got it, but I'm assuming they're probably all 01A's. Whoever built the thing back in the 20's installed four binding posts for battery connections. One is marked "A+B-", the second "A-", the third "B+" and the fourth "Amp". If this thing uses 01A's, the A voltage would be 5-6 volts. I'm not sure what B voltage to apply to the B+ and "Amp" (which I'm guessing is a higher B voltage). There are two interstage audio transformers, the first being a 10:1, and the second a 3:1. I don't want to fry anything when I get ready to power this thing up. Would 22.5 and 90 work?
::
::Thanks///Jeff



© 1989-2025, Nostalgia Air