I want to update the old-fashioned clamp-tube circuit.
I want to create a solid-state switch that will accept a voltage input
(negative, but it
can be inverted) derived from the rectified grid current of my class-c
amplifier. When
this input is present, I want the switch to connect the amplifier screen to its
power
supply; when it is not, I want to disconnect the screen voltage.
I am thinking of a circuit similar to the series pass transistor that is used
in regulated
power supplies; but of course the transistor will have to be rated to handle
the 400V
screen voltage (the current will be 80 ma). My amp has a separate screen supply
producing
the 400v.
Unlike the shunt clamp circuit, this won't waste power by pulling down the
voltage across
a resistor -- it will just be a switch.
If this makes sense, what would be a good choice for an NPN power transistor,
something
like a 2N3055 with a higher voltage rating, that could do this? Any other
ideas? The
keywords are cheap and available.
I apologize for still living in a world of 6L6's, etc.
--
Vic
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