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Re: Big Triode Tubes
Tesla List wrote:
>
> >From MALCOLM-at-directorate.wnp.ac.nzThu Sep 5 22:26:04 1996
> Date: Fri, 6 Sep 1996 14:09:46 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: Big Triode Tubes
>
> Just a thought if anyone considers rewinding a neon for a bottle
> power supply...
>
> > > How about an ARC welder! I'm being sarcastic, the tube I'm
> > >looking at is 7.5 V at 100 Amps on the filament. I'll probably use
> > >a balanced neon for the plate, but I'll need to experiment and find
> > >what filament currents will work. I already recognize that if the
> > >current is to low, it will take forever to heat the tube.
> > >
> > Dan,
> > How about a "blown" neon for the filament supply? 7.5V -at- 65A
> > is 12 turns of #4 on 1 half of my dead jefferson 15kV 60mA neon.
> > Winding the other side with the same number of turns will give you
> > 7.5V -at- 130A. You could also put half as many turns on each side and
> > then put them in series to put the center tap to ground.
>
> You could pop a heater winding on one leg and a suitable HT winding
> on the other for an all-inclusive compact supply. The insulation
> should certainly be there.
> I wonder about the wisdom of using the shunted core for a
> filament supply though. Seems to me that voltage regulation will be
> rather poor.
>
> Malcolm
Malcolm,
I've also considered this, since most tubes can only tolerate
a 5% voltage shift. But, according to the manual, this will only
shorten the tubes lifetime. Now as far as oscillator performance, I'll
check it out with an "O" scope. One thing I could do though, is to
raise the voltage from the transformer to say 10 Volts and run a
couple of hugh semiconductor rectifiers in series. Using some Capacitors
for balancing and utilizing the inherent voltage drop of the rectifiers,
I should get what I want.
D. Gowin