[AMPS] Re:HV on tube w/o filament voltage

[yo3ctk@qsl.net]

Jon wrote:

Got a question:  How hard is it on a tube to have the HV applied to the
plate w/o the filaments turned on.  The reason I ask is that unknown to
me, a relay must have stuck in my power supply control unit and when I
turned my amp off, the voltage to the HV transformer was never turned
off.  So I thought the amp had been completely shut down and it wasn’t.
I discovered this just prior to the contest on Friday when I went to
turn everything on and noticed the HV supply cabinet was very warm.
Then I noticed the HV meter still read 6KV!  It was like this for
several days.

Jon,

If your power supply was "very warm" with zero current, how warm it was
after heavy use during contest ?

But you have raised an interesting question. I would like to add another
one: Is it allowed to apply HV along with filament voltage at start-up,
provided that G1 is biased at cutoff and G2 voltage is zero? The tube in
question is a 4CX800A. Svetlana says no way.

73 de Mike, YO3CTK



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