Clamp It! G3HUL tells all!

[WA4WAX]

See page 46.

I know, someone rotated the pages.  Uggh!

http://www.americanradiohistory.com/Archive-Radio-Constructor/50s/RC-1955-08.pdf

[Opcom]

Here's a helped version of just the article!

[WA4WAX]

Thanks for the clean up!

The idea of running feedback from modulator tube to driver is interesting.  This approach would be good for a pair of 4D32's.  I wonder if you could get the mod depth up to about 90 or 95% with low distortion.  That would be fairly impressive.

BTW, Mr. Mallett was still alive and active with RSGB as of 2009.  Perhaps he is still around...................

[DMOD]

This is also called a "shunt" modulator.

The Ameco TX-86 used this same modulation method and sent some of the audio to the Final's grid bias circuit as well as to its screen.

The shunt modulator is a power hog since the modulator tube has to operate in Class A with a high plate voltage.

A better method is to use a cathode follower to modulate the screen voltage and send a small fraction of audio feedback to one of the speech amplifier stages.

Phil - AC0OB