Does it do this with a cold filament?
Regardless, have you gettered it by running the filament by itself for a
length of time? That's a must for those tubes before using them.
Type these (and variations) words into Google: gs-35b getter
I'd send you some links, but they are on another one of my computers.
73, Mike
www.w0btu.com
On Wed, Feb 25, 2015 at 2:39 PM, nemo zilch <nemozilch@gmail.com> wrote:
> Hi-pot tested my GS-35B and it breaks down at about 5600 volts at the tube
> plate. I have a 10 Meg resistor in series going to the tester to limit
> current. When it breaks down the voltage goes to a few hundred. The
> current on the micro ammeter pegs the needle, on a 250 microamp meter. The
> breakdown is very sudden and sharply defined, almost like a switch has been
> thrown. Before breakdown I cannot see any current at all even on a 15
> microamp meter.
>
> Does this sound like the tube is gassy or is it arcing? I plan to apply
> about 2000 volts and I think I can supply enough current to put about 1200
> watts or so into the tube. I'll let it cook for a good long while and see
> if the heat helps the situation.
>
> Anyone know what breakdown voltage I should expect. I don't know if a 5600
> volt breakdown is typical or if there is something wrong with this tube. I
> am planning on using about 3800 volts in the amp I am going to build. That
> will produce a peak RF voltage of something a little over 7000volts at the
> plate. This tube cannot be used for that, could only run something around
> 2500 volts.
>
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