The AM Forum

THE AM BULLETIN BOARD => Class E Forum => Topic started by: KI4YAN on July 19, 2020, 05:31:38 PM



Title: Not quite class E-but Class D...hollow state!
Post by: KI4YAN on July 19, 2020, 05:31:38 PM
So a few years ago I sponsored a contest on another electronics forum, and issued this challenge-Build a single-channel audio amplifier using ONLY dissimilar section tubes, and you must use all sections. No dual triodes, no single pentodes, etc-each section must be different.

Tim, as he usually did at the time, decided Class A wasn't good enough, so built the Borg. And he won the contest, handily.

https://www.seventransistorlabs.com/tmoranwms/Elec_Compound2.html

Tube based PWM generator and class D output...in tubes. Gets reasonably close to mosfet performance, too. Maybe applicable to Class D AM transmitters, if you really wanted to go the difficult route!


Title: Re: Not quite class E-but Class D...hollow state!
Post by: Opcom on July 21, 2020, 06:06:00 PM
Efficiency and power isn't everything. Remember, weirdness counts!


Title: Re: Not quite class E-but Class D...hollow state!
Post by: Steve - K4HX on July 22, 2020, 12:15:31 PM
Several of the east coast AM gang have built tube based PDM modulators for tube final rigs, some as far back as the 1970s or 80s.
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands