Power Supply for a 1920's Radio

by Chad Hauris

Updated 8/8/05

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We have had some customers who have 1920's era radios which use type 01A tubes and were designed to run on batteries. One lady can remember when she was young, and they hooked up the radio to the T-model Ford battery.

These radios actually require two battery supplies...one for the tube plates (this is called the B supply) and one for the filaments (this is the A supply). Sometimes a negative bias supply (the C supply) is needed.

Sorber Radio and Speaker

1920's Sorber radio with Atwater Kent Speaker .

In the 20's, the Model T Ford battery or other such storage battery would have provided the 6-volt A supply for the filaments. The filament current draw is around 1.25 amps. The B supply would have come from large dry-cell non-rechargeable batteries. As the current draw for the tube plates is fairly low (around 15 milliamperes) this battery would have lasted a long time.

So, we needed to construct a fairly high-current, low voltage supply for the filaments, and a higher voltage supply (at 90 and 22.5 volts) for the plates.

Continue to the power supply construction page.

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