[Amps] High frequency heater supplies

[Jim Tonne]

Steve wrote:

> Does anyone know if there are problems using high frequency (say 30kHz) 
> ac to run the heater in a valve with a cathode? For that matter, the 
> filament in a valve without a cathode?

If line-frequency (50 Hz or 60 Hz) power can cause a small amount of
modulation of the RF output, then I would think 30 kHz could do the
same thing.  The output signal would then have sidebands at +/-
30 kHz from carrier, down maybe 40 or 50 dB.  I suspect this
would be an issue mostly with directly-heated cathodes.

- Jim WB6BLD