[Amps] DC heater supply or AC heater supply

[G3rzp at aol.com]

I like the idea of a DC heater supply. However, there seems to be no information available on the effects of metal migration in the heater/filament, which, considering the currents involved and the temperatures, may not be insignificant.

Reversal of heater/filament polarity may be worthwhile on each switch on to minimise this problem.

73

Peter temporarily W6/G3RZP