On Wednesday, 25 April 2018 07:58:34 UTC+1, wrote:
NT:

"Would you really need to stack LOP tubes? "

I think the max plate voltage of a 6MJ6 is about 5 KV, so it wouldn't quite do it, even bridged, I think.

Picking the first random ES design I see 475v dc bias.


"The most common way to do reduced power in the early 70s was with an HV cap & HV switch."

You mean like a lower value cap for the lower power level ?

2nd smaller cap in series with the ac HV feed, shorted for full power.

"It's how they used to run bright emitters in the 20s. "

What is a "bright emitter" ?

before dull valve emitters were discovered, valves/tubes used thoriated tungsten direct heated bright emitters. They ran white hot. Nuke magnetrons use thoriated tungsten bright emitters.


NT