Re: First VTTC light, and a few questions

["David Sharpe" <sccr4us-at-erols-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Ed, Terry, ALL

In checking several sources for VT's, I checked PentaLabs
(www.pentalabs-dot-com).  The ratings on the various 833 variants are
listed below.

               833A            833C            833D
Fils V        10VAC        10VAC        10VAC
Fils I          10A             10A               11.5A
Plate P      350/450*    400/550*       450/600*
Cost           $105            $115            $128
Shipping and Handling <$20 for 2 tubes

Costs were quoted April 2000, check for current availability and
pricing.

* Forced air cooling, ICAS ratings, 40CFM between grid and plate
glass seals

Power input on all tubes are published at "only" 1800W.
The 'A's I would believe that, but your coil is running 4-5kW input
if memory is right, without graphite plates running hot?  The 'D' is
a relatively new tube (1yr +) and has higher reserve cathode
capacity, plate dissapation and longer life for only a pittance higher
cost.

On my new high power P-P VTTC I will be going the 'D' route.
I also think if the tubes are properly hardened and prepared for
service, 5-6kV should be fine on AC service (John Freau was
running his super 833A x 3 coil from a 7.2kV PT).

Regards
Dave Sharpe, TCBOR
Chesterfield, VA. USA

Tesla list wrote:

> Original poster: "Edward Wingate" <ewing7-at-rochester.rr-dot-com>
>
> Tesla list wrote:
> >
> > Original poster: Tesla729-at-cs-dot-com
> >
> > Hi all,
> >
> > While we're on the tube coil topic, I am a tube coil virgin (never built
> > one),
> > and I was wondering if someone could point me toward a good reasonable
> > source for large vacuum tubes (811's,833's, ect). I've been thinking about
> > taking the tube coil leap lately and I already have several MOTs and also
> > one beefy 2200v, 1A plate xfmr. Thanks in advance for your responses,
> >
> > David
>
> David,
>
> RF Parts in California isn't a bad place to start. I've had good luck
> with them in the past. That's where I bought the 833Cs for my own toob
> coil. If you make the leap, I'm sure you'll enjoy the experience.
>
> http://www.rfparts-dot-com/
>
> Ed Wingate RATCB