Re: 813 tube tc coil

Hello, with two 803's I obtained 7 inch (17.8 cm) discharge. The 813's are
very similar, IIRC, graphite plates and all, only that the 803=2000V on the
plate; 813=2500V (RATED). So with a pair of 813's you should be able to see
18 cm+ discharge in a tube coil. I would suggest tying the grid, screen,
etc together pretending they were a triode. That was most successful for me
with the 803's, did run them as a pentode, but was only able to get 5 inch
(~13cm) discharge. You can see the 803 in action on my web site, if you
care. Also I am going to be placing design schematics for the 803 at my
website, eventually... But if you are interested in specifics let me know
via e-mail or this list-server. I suspect binaries are no longer
transferred via list-server? So if you want my schematic for the 803 coil I
will send it off-list.


David Trimmell

Tesla Tube Info -at-: http://www.pond-dot-net/~davidt/webdoc2.htg/Tubez.htm

At 10:31 AM 3/13/99 , you wrote:
>Original Poster: Mazzilli Vladimiro <mazvla-at-iol.it> 
>Hi all
>I've asked about te wiring of a tetrode or a pentode in a tube TC coil
>and Someone Have me  suggested to tie the three grid together, but in te
>triode connection of a tetrode or pentode, te tube will not run at full
>plate rating voltage (for 813 =2500V)
>is better to tie te last grid to te filament (dynamic connection), and
>the screen grid appropriately connected by a resistor (in general
>variable to fix the oscillator plate current), at rated grid maximum
>voltage. The reason of that is that in Italy is very difficult to have a
>power triode for a cheap price, I've read in USA for a 833A a price from
>20 to 50 USD; in Italy if you have a good luck to find it, you have to
>spend about 150 USD or more.