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Re: plate voltage



Original poster: "sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>

Hi All,

         You can safely push a voltage doubled MOT into an 833 at 120v into 
the MOT without any trouble.  The absolute max DC voltage on the tube is 
4kvDC I believe, though I've peaked mine up to about 5kv without a 
flashover.  I don't know what the max voltage on the 572B is.  You do need 
to keep an eye on the maximum current you're pushing into the tube though, 
especially when you start running it consistently at the limits of the tube.
         All in all, if you stick to the numbers the manufacturer gives 
you, you'll insure a good life for the tube.  The plate voltage is nowhere 
near as important as the filament voltage.  Make sure you're dead on with 
what the manufacturer says.  Too low, and the emission falls off (total 
power out goes down), too high and the filament life is reduced 
rapidly.  Don't settle for 1/2 a volt, make sure it's dead on.
   Another interesting bit here, when putting the RL chokes on the grid of 
the coil, scavenge the back of the magnetron.  There's 2 nice ferrite core 
chokes in there that do wonders for cleaning up the tube's switching when 
put in parallel with an 8 ohm resistor.

Hope it helps!

At 12:38 PM 3/19/02 -0700, you wrote:
>Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><FutureT-at-aol-dot-com>
>
>In a message dated 3/19/02 10:32:06 AM Eastern Standard Time, tesla-at-pupman-dot-com
>writes:
>
>
> >
> > Gentlemen:
> > What is the maximum plate voltage AC that has been tried with 833-A and 
> 572B
> > tubes without flashover?
> >
> > The 833A can withstand more voltage than the 572B I think.  I'v
>
>e
>
>used 833A's but not 572B's.  I've used a max plate voltage of about
>6kVAC with 833A's, but they tend to flash over when they get hot
>at that voltage.  5kVAC is a safer voltage.
>
>Cheer,s
>JOhn

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Shad (Sundog)
G-2 #1203
"Ever stop to think, and forget to start again?"
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