You could build a power supply and connect positive lead to B-. This will give you a voltage more negative in relation to B-.
Your radio uses this negative voltage as bias on the output tube. Most likely a 71A. You could wire batteries in series and use this for the negative voltage. Current will not be drawn from this supply so batteries will last their shelf life.
Norm
:Hello all.I recently purchased a Crosley model 143 farm battery radio.It has no vibrator.I am also getting a power supply with B and A voltages.How do I get the -22.5 volts.I know how to get positive by using voltage divider but not negative.I don't want to use any silicon diodes I am a purist .Can you reverse leads or could I use a 6H6 diode with a capacitor(filter)I don't quite understand this and I don't want to depend on batteries.Any help would be appreciated.Chris
This radio does use a resistor voltage divider on the C voltage so a power supply is the best way to go. Batteries would need to be disconnected when your radio was turned off.
http://www.nostalgiaair.org/PagesByModel/271/M0003271.pdf
Norm
:Hi Chris
:
: You could build a power supply and connect positive lead to B-. This will give you a voltage more negative in relation to B-.
:
: Your radio uses this negative voltage as bias on the output tube. Most likely a 71A. You could wire batteries in series and use this for the negative voltage. Current will not be drawn from this supply so batteries will last their shelf life.
:
:Norm
:
::Hello all.I recently purchased a Crosley model 143 farm battery radio.It has no vibrator.I am also getting a power supply with B and A voltages.How do I get the -22.5 volts.I know how to get positive by using voltage divider but not negative.I don't want to use any silicon diodes I am a purist .Can you reverse leads or could I use a 6H6 diode with a capacitor(filter)I don't quite understand this and I don't want to depend on batteries.Any help would be appreciated.Chris
Took a quick peek at the print for your 143. If you are getting the A & B supply already. I would think you should be able to just build a DC filtered power supply that would be a separate board, or little chassis from the other. The hook up looks basic and simple. as to use a 6H6 for a rectifier I don't think that's the best thing to do. Just adds more wires and heater draw. But it is a low voltage rectifier. You can do that if you want to. Silicon diodes if it were me.