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Re: 810 tubes
> Date: Sun, 19 Jan 1997 22:25:08 -0700
> From: Tesla List <tesla-at-poodle.pupman-dot-com>
> To: Tesla-list-subscribers-at-poodle.pupman-dot-com
> Subject: Re: 810 tubes
> Reply-to: tesla-at-pupman-dot-com
> > Subject: Re: 810 tubes
>
> Subscriber: ewing7-at-frontiernet-dot-net Sun Jan 19 22:02:30 1997
> Date: Sun, 19 Jan 1997 14:45:36 -0500
> From: "Edward J. Wingate" <ewing7-at-frontiernet-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Re: 810 tubes
>
> Tesla List wrote:
> >
> > Subscriber: ulflyer-at-juno-dot-com Sat Jan 18 22:35:58 1997
> > Date: Sat, 18 Jan 1997 19:59:55 PST
> > From: Stephen G Stanton <ulflyer-at-juno-dot-com>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: 810 tubes
> >
> > All:
> >
> > The Chinese tubes are generally junk; even at those prices (??) I
> > wouldn't waste my time on them;. They go flat fast. Save your money
> > and use good old USA tubes if you can find 'em. Eimac is still the
> > best.
> >
> > Stephen, KJ6LH
>
> Hi Stephen and all,
>
> I can't speak for other Chinese tube numbers or manufacturers, but I
> have been using 2 833c's from R.F. Parts in CA. ( the tubes carry the
> R.F. Parts brand name) in my vacuum tube coil for the last two years and
> they continue to work just fine. In fact it is difficult to get the
> plates to glow dull red at 7+ KW. With standard metal plate tubes I have
> to monitor the input carefully to avoid melting the center of the
> plates. Spark output about 24" in case you were wondering.
>
> Ed Wingate
Ed,
Welcome aboard Chip's List! Hey everybody, Ed here is one of the BIG
BOYS in coiling (Ed, from what I've seen you deserve such credit!).
Please accept my heartfelt support on your obviously high level of interest
driven coiling activity and a fine and spacious coiling lab. Perhaps
I will get a chance to meet you in the near future to share and
compare coiling joys. : ) I've seen the impressive web photo of your
tandem system and praise you for approaching the famous Tesla photo
*look* of apparent recklessness in it. The first impression I got from
that photo of apparent lack of personal safety _must_ have been _carefully_
orchestrated! Either that or you are in reality just as crazy as me! ;- )
You certainly HAVE pushed a pair of 833C triodes in your coiling
experience!
Those carbon block plate versions 811-C I've been hearing about
recently, and now your report on the 833-C seem to indicate that
these carbon anode toobz really seem to take the plate current! I have experience
with four 833A's in parallel (the sheet metal plate version), and I know exactly
what you are talking about when you worry about melting a hole in the middle of
the broadsides of the plates. The RCA tube manual actually says that
orange plate color here _is acceptable_ in CCS with adequate airflow
on the seal/lead areas of the envelope. Trouble is, if you go just a
tich above yellow/orange in a small spot you will probably make a hole!
O.K. CNN, start rolling your tape!:
"Tesla coil, high voltage resonating secondaries inserted at some value of K
(usually high) into the tank circuit of a vacuum tube power oscillator do not
emulate the predictable and stable VSWR load to such an oscillator that a lamp or
resistive load can represent." My own quartet of 833A's produced a measured
3500 W RMS into a lamp load without any plate color with just 3 KVDC
full-wave filtered on the plate supply. Replacing the 4 turn lamp
load winding with the HV resonator makes the toobz go cherry/orange!
The wild and wonderful world of plasma you can
create with a Tesla HV oscillator becomes a rapidly changing world of
free air voltage clamping and impedance parameters based on numerous factors
including ambient temperature, humidity, wind, air polution content,
terminal size and shape, proximity effects to conductive or
dielectric bodies, etc., and possibly the way you hold your mouth!
The point of this rambling is : Numerous circumstances in addition to your
discharge terminal shape and size will harmonize to effect a
resultant streamer display. Having the unfortunate experience of your tube
electrodes (not just the plate) melting during any one of these operational phases
is an easily accomlished effect, and is one to be avoided at all cost through low
power evaluative/progressional power testing of a any tube coil system.
High power vacuum tube Tesla coiling can ONLY be orchestrated at
relatively low cost when care and thoughtfullness are employed in the
design process. Hooking up a pole transformer to an untested tank
circuit using a single 811-A triode tube may quickly result in big sparks,
but only once.
Ed, I've wandered off topic here on a subject that we are all
obviously interested in, in the hopes of adding further insight to
the less/more experienced, and newer/older members here. Replies on
Chip's list are essentially front page newspaper articles. Forgive
me/thank me please for rambling so.
Ed, I would be interested in further tech details of your toob coil
system if you wouldn't mind sharing.
regards,
rwstephens