bill ramsay wrote:
dear all

I am playing with some 813's at the moment. I am trying to get the
heater supply sorted out.

the 813 needs 10v at 5 amps, the do glow v. bright when lit up.
pretty neat.

I would buy two 5v switching supplies and wire them in series. Both of
these surplus should cost less than the heatsink for a TO-3 transistor.


Adam