Re: 813 tube tc coil

Tesla List wrote:

> Original Poster: David Trimmell <davidt-at-pond-dot-net>
> 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.
> Regards,
> 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.
> >
> >
> >sincerely
> >Vladi
> >

    David, the length of the spark , you mentioned in the post, is measured
with             somekind of toroid or only the electrode at the top of the
Because with this last type of measurement I obtain 5" on 3X807 tube TC working
at only 700Vac plate voltage with a tetrode connection.

P.S I've seen your site it's very beautiful.
If you have not yet seen the mine you can look at
Happy Sparking