On Jul 3, 9:37*am, Jack Schmidling wrote:
The link below seems like something hams should have done long ago. *I
assume there is some reason not to but thought I would float it here.

The front end is easy and has been done many times for Class D and
Class E transmitters.

The unique part is the stacking of low voltage modulators to achieve
high voltage for tubes.

Seems like scaling this down to our power levels would be pretty
straight forward but I don't happen to know how to do it.

Wa1QIX has a PDM Modulator board/kit that I have on order which solves
most of the front end details but the series modulator boards are beyond
my pay grade.

Anyone on this list have any interest or ideas on the subject?

http://www.contelec.com/SSM.html

Jack K9ACT

Astronomy, Beer, Cheese, Fiber, Gems,
Nature, Radio, Sheep, Sausage, Silver

* * * *http://schmidling.com

Seems like mainly you need a way to feed the audio into each of the
amplifiers, and power supplies for each amplifier such that the amp
can "float" up and down at a high enough rate. That is, any
capacitance to ground must be driven by the amplifiers below. The
audio input must have good common mode rejection. That's not
necessarily terribly difficult, just a requirement. It could be done
with transformers, but an interesting variation might be to have an
output from each amplifier to drive the amplifier above it in the
chain. One other thing: if you are wanting to do it as suggested on
the CE page you linked to, you need amplifiers that output nominally 0
to +V, not +/-V, and are happy to deliver highest current at the +V
peaks. I assume to start with that you don't need to do the
controlled-carrier thing. I suppose to do that you'd want input
coupling all the way down to DC.

Cheers,
Tom