Loy Barton of RCA wrote one of the first class B high power audio amplifier reports. He developed the concept of plate modulation with a high level push pull audio driver for his thesis at Univ of Arkansas radio station. You can read the report from 1930 here:
http://www.amwindow.org/tech/htm/tutor.htm I summarized the events which led to Barton's paper in QST in 1931, followed by Art Collins paper in 1935 on the benefits of this approach. http://www.amwindow.org/tech/htm/heisingorwhat.htm 73 John K5PRO > Message: 4 > Date: Wed, 15 Feb 2006 18:48:52 -0500 > From: "Mike Sawyer" <[EMAIL PROTECTED]> > Subject: Re: [AMRadio] AM Transmitter Advice?? > To: "Discussion of AM Radio" <amradio@mailman.qth.net> > > Don, K4KYV said: Sometime in the late 1920's, it occurred to someone that > class-B linear > amplification would work just as well for audio as for rf, and the class-B > audio amplifier was developed. The unusual thing about this setup was the > large audio transformer required. Many rf linears were single-ended, and > depended on the fiywheel effect of the rf tank circuit to supply the missing > half of the sinewave output. With class-B audio amplification, the tubes > have to be in pushpull in order to reproduce both halves of the sinewave. > Thus the well-known "class B modulator" came into being. > > Interesting that you mention this Don. I just read where it was Art Collins > and his group that came up with the idea of using Class B push-pull audio > for Class C rf amplifier. I'm not a Collins aficionado but Joe, N3IBX gave > me the book, "The First Fifty Years of Collins" to read and I found it very > good reading. There was some self-promoting in there but I was mildly > surprised when I learned Collins did discover the Class B P-P plate > modulation scheme. > Mod-U-Lator, > Mike(y) > W3SLK > >