Roy Lewallen wrote:
It sounds like a technique I remember calling "controlled carrier". The
carrier power was reduced when you weren't talking, then was increased
with the audio in an AGC-like manner. Sounded a little weird, but not
badly distorted. The objective was to reduce the average dissipation of
the final stage, so smaller tubes and a lighter duty power supply could
be used.

No, "controlled carrier" was something else.

In 100% positive modulation, the carrier amplitude is constant
regardless of program material. You (somehow!) maintain proper absolute
phase through the chain so that you know a positive-going audio signal
at the transmitter audio input terminals will result in increasing power
in the modulated carrier. You then allow the positive-going signal
peaks to exceed 100% while limiting negative-going peaks to less than
100%. Broadcast modulation monitors are able to display negative-going
and positive-going modulation peaks independently.

(at a broadcast station, the FCC requires that carrier power be between
-- IIRC, my copy of Part 73 is missing -- 80 and 110% of the authorized
figure. DX-60B-style controlled carrier wouldn't comply, though I
suppose you could develop a system that didn't swing the carrier quite
as far.)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com