[AMRadio] WTB/WTS and a question

Mike Dorworth, K4XM k4xm at arczip.com
Fri Dec 30 15:35:28 EST 2005

> > > > The tubes all have 2V filaments.  The radio has two inputs for a
> >
> > > > filament
> > > > supply, 2V or 2.5V (the 2.5V input merely inserts a series
> > > > resistor).  My
> > > > question is....why did anyone manufacture 2V filament tubes and

>Two volt tube were used in the 19 twenties and thirties for FARM radios.
They used a 2 volt wet cell. One third of a car battery for those tubes.
Also The audio always push pull class B triodes for maximum B battery
utilization. Folks carried the cell to the service station or perhaps had a
windmill generator from a T model Ford connected for recharging. REA did not
start until about 1933 or so and almost no Farmer in America had Electric
power. The dry B batteries were 135 volt and lasted a long time but many
units had a vibrator pack that ran off a 6 volt wet cell battery from a car
or the Edison Electric Company. By the mid 1930's the 230's etc were amost
obsolete. Hope this helps HNY, 73 Mike

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