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Re: 810 tubes



Tesla List wrote:

> Subscriber: rwstephens-at-headwaters-dot-com Mon Jan 20 22:29:35 1997
> Date: Mon, 20 Jan 1997 20:03:01 -0500
> From: "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: 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! ;- )

Hi Richard and all,

Thanks for the kind words Richard. I appreciate your comments, but, I
also have to say that the number of folks across the nation who are
doing outstanding Tesla Coil work is truly amazing.
My lab was a long time coming, and I do enjoy it. A little advice to
anyone out there who is planning a lab....decide how large you want it
to be ... then build it twice as big and it may be big enough.
The photo has been a lot of fun. Especially when folks don't realize
that it is a double exposure, just as Tesla's famous photo was. I may be
a little crazy, but I don't have a death wish.
Meeting other coilers in person is always great. It's fun to wail on the
equipment for someone who shares the interest!

> You certainly HAVE pushed a pair of 833C triodes in your coiling
> experience!

You know how that goes. Nameplate ratings are only a starting point for
coilers. Vacuum tube coils are also notoriously ineffecient.

> 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!

Four 833's? That's enough to heat your basement. Yes, orange is OK,
radio stations ran them that way day in and day out, but any more is not
good. 
> 
> 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!

Toob coils do certainly put out the RF amps. That's a lot of power.

> 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.

Not at all. The coil I have was featured in the Volume 10 #1 Jan. Feb.
Mar. issue of the TCBA newsletter and was designed by John Wiesner. I
will check with Harry Goldman to see if it's OK to post the article for
anyone who is interested. The back issues of the TCBA news contain a
wealth of information such as this.


> 
> regards,
> 
> rwstephens