Hi,
Rich wrote...
> // Sounds good. How did you protect the screen from loss of anode
> potential?.
This reminded me of a 4-65A amp (class C) that I built for 40m many
years ago. After installing a bigger fan (cooler is gooder) I hooked
everything back up to the power supply, which was in a separate
cabinet.
Well, almost everything. Not the anode supply; but the "stiff"
screen supply was connected.
The first time I keyed up, the screen potential was applied, and the
tube performed like one of the old focal-plane shutter type
flashbulbs. It gave off a very bright light, nearly white... none of
that wussy orange color... for a fraction of a second (1/4? 1/2
second?)and I was left with a 3-65A.
It was an expensive show in a brief time.
In my tetrode amplifiers since that time, screen voltage application
always requires the presence of appropriate anode voltage (and
appropriate control grid bias, as well!) whatever the method of
screen regulation (or lack thereof.)
73,
George Daughters, K6GT
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