[Hallicrafters] Bucking Transformer

[David Thompson]

Years ago I had a big auto transformer that we mounted above the power 
supply
for a 4-400 amplifier.  Almost everything in those days was on 110V AC and 
we had a big 50A circuit.

The auto transformer allowed me to step up the voltage to about 145V and 
down to less than 40 volts.  One of my elmers W5DYJ said this was better 
than a variac.
I think it had at least 10 or 12 steps.  I recall the transformer weighted 
about 50 pounds and was made by transformer Corporation of America in New 
York.  W5DYJ had Masters and PHD's from Columbia so New York made sense.  I 
found Frank Lester W4AMJ Ex W2AMJ worked for them in the early 1950's.

The main times the auto transformer was used was to slowly test out a new 
4-400 and to reduce power to less than 150 watts input using a 4-125 so I 
could operate the ARRL Phone SS (AM phone).  I found one of the 4-125's used 
back then in my junk box.  I always got a signed statement from a local club 
official that I was running 150 watts input or less.

So guess I ran a bucking transformer years ago.


73 Dave K4JRB