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
