R-390A: feeding oscillator tube heaters in DC, w/o regulator tube?
I solved this by running the 12.6VAC center tap from the power supply
to pin 5 of the regulator tube. Insert a jumper from pin 5 to pin 7
and you're in business. This also allows the jumper to be removed and
a regulator tube can still be used if you'd like.
Barry - N4BUQ
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