Antique Electronic Supply K-101A A-B-C Battery Eliminator

In today’s world of antique radios, most are not completely original down to the smallest component. The reason as described in the Philco Model 116X page is aging failed components.

Radios from the roaring 20s were built of primitive components and they did not go bad with time. These early bear skins and bone knives radios did not get hot. Resisters were wire wound and oversized. Capacitors were made of mica and copper cladding; virtually indestructible. It was when manufacturers went to wax, paper, aluminum, carbon, cathode tubes and higher voltages is when a radio’s vital components started failing with heat, use and age.

The radios that can be found which are still all original are often times those that are pre-1930s tuned RF radios and were powered by multiple battery types rather than an integrated AC power supply. This may also include early superhetrodyne battery radios.

The problem with these battery powered tube radios is they require 3 independent isolated power sources such as a high voltage supply, a filament supply and sometimes a biasing supply.

Modern-day retro all-in-one A-B-C power supplies often come in assembled form with their design specific to certain radio types.

The AES K-101A is a fully regulated universal power supply that addresses most of the requirements of antique battery radios including 1940-50s battery only miniature tube radios.

This is my Tube Radio Battery-Eliminator power supply. It was built using the K-101A Battery Eliminator Kit from Antique Electronic Supply.

A Battery filament supply: 1.2 to 6 VDC up to 1.5 amps.
B Battery plate supply: up to 50MA @ 22, 45, 67, 90, and/or 135 VDC
C Battery bias supply: 0 to 22 VDC.

All three supplies are variable voltage. Each of the three sections are independently isolated from each other enabling them to be connected in series, i.e., the C+ bias supply can be connected to B- for a negative bias supply.

GND – Case/Earth Ground

For 90% of 1920s radios this supply is a godsend. There are radios with more than six tubes that this supply’s filament supply of 1.5 amps is insufficient. However, these radios are a rarity, especially if they are battery powered. Also, a plate supply of 50MA may not be enough for radios with high powered amplifiers. But these radios that were battery powered are extremely rare.

So, for most radios, the K-101A is an excellent power supply with lots of versatility.

Note. I found it was cheaper for me to just order the kit for $54.95 rather than spend so much time scrounging around for all the components. The custom transformer used in the K-101A is rather unique and hard to find.

S March 2019