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Re: 813 VTTC Problems

Original poster: FutureT@xxxxxxx

In a message dated 8/29/05 3:36:08 PM Eastern Daylight Time, tesla@xxxxxxxxxx writes:


Original poster: "Chris Fanjoy" <zappyman@xxxxxxxxxxx>

   Still trying to get this dual 813 VTTC going, with no luck. The
main problem right now is figuring out what to do with the extra
grids (G2 and G3) of the 813 tubes.



The easiest approach is to tie the control grid and the screen
grid together and use the combo as the control grid.  The suppressor grid
should be grounded to the cathode.

If you want to run the screen grid separately, use a 40k ohm resistor
of about 100 watts.  It will draw some current in it's role as a dropping
resistor.  You want about 700 volts on the screen.  These resistor
values are for a single tube.

In my setup I used a level shifter (ac doubler) MOT and obtained
16" sparks without staccato from a single 813.  Longer sparks
are probably obtainable with some better adjustments.  I show some
similar schematics and stuff at my website at:

  http:hometown.aol.com/futuret/page3.html


John