[Amps] Switching Supplies for High Current Filaments

[Radio WC6W]

Hi Paul,
  Acceptable on an indirectly heated tube.

  This will cause trouble on a filamentary type as even though the filament is structured to minimize the effect some modulation will occur.  This is not generally noticable with (50-)60Hz operation but, at 20-100Khz the sidebands will be evident.

  Also on a GG design, the filament choke will have substantial reactance at the switcher frequency creating more problems...

73 & Good morning,
  Marv WC6W 

http://qsl.net/wc6w/

--- On Tue, 10/5/10, Paul Decker <kg7hf at comcast.net> wrote:

> From: Paul Decker <kg7hf at comcast.net>
> 
> What if instead of DC, the square wave (triangle or
> whatever) from the switchers transformer were used? 
>