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Re: 833 coil



Original poster: "James" <mustang3-at-cox-dot-net> 

Hi John,
     In answer to some of your questions. Use a mot for the filament xmfr.
The exact number of turns to put 10V. exactly at the toob(about 10 turns).
Use a mot for the H.V. xmfr. Jive old voltage doubler(the rectifier is
reversed from the uwave). The uwave H.V. diode prolly won't go too long. I
use 16 6A.-at-1000V. diodes in series. About a 4" dia. X 24" high secondary;
#27 wire will soak up one 833 just fine(and will be ok for two toobs as the
bug bites). I have always had flashover problems(pri to sec). I recomend 2"
or more between pri and sec. Put the primary winding on top, with the
tickler winding an inch or so below it. I use mica caps for the plate cap
and the grid leak cap. The plate cap needs to be double the applied voltage
on the toob. i.e. uwave voltage doubler is 4400V. or so then a 10KV cap is
needed. As for reliable operation, the tube(833a here) should only be bright
red. As it becomes red-orange, it's closer to death. 833c's can be run
red-orange and even hotter.
     Look on Ralph Hartman's site and you can see some pictures of both my
toob coils. One horizonal and the vertical coil. Contact me off list and I
can email you pictures, schematics, or even advice.

Later,

James
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, September 26, 2003 9:27 PM
Subject: 833 coil


 > Original poster: "John Richardson" <jprich-at-up-dot-net>
 >
 > Hi,
 >
 > I recently acquired an 833a tube, and would like to proceed with making a
 > coil.  The only requirement that I want to impose on this project is
 > longetivity, even at the expense of spark length.  The goal is to be able
to
 > run for extended periods without worrying about tube damage, allowing for
 > various experimentation.
 >
 > Due to time constraints, I am hoping plagiarize a working, single tube
 > design.  After I have an operational coil, I can then proceed to alter
 > parameters to notice their effect.  Also, due to a relative lack of
 > knowledge with electronics, I believe that going with an existing design
 > will allow for a better learning experience than continuously fiddling
with
 > component values that I know nothing about.  Here goes:
 >
 > 1)  10v 10A filament transformers seem impossible to find.  Would I be
able
 > to use the trans out of a 12 volt battery charger and throttle it back
with
 > a variac?  Or, would it be better to use a MOT with the secondary removed
 > and wind a few turns of wire on it like everyone else has done?
 >
 > 2)  Plate transformers designed to feed an 833 are super expensive and
 > heavy.  MOTs again?
 >
 > 3)  Does anyone have a link with a solid, simple one tube design that they
 > would be willing to share?  It's my understanding that a lot of the
 > component values aren't critical, but since I'm the type of person who has
 > to be hands on to learn, they would assist me in getting together a
project
 > where results can be seen.
 >
 > 4)  I have gone thru the archives and done lots of reading on other's
 > projects to alleviate you guys from reiterating what has been said many
 > times, as well as making countless visits to Steve W's, John F's, and
others
 > websites.  I've read the tube section of my old AARL Handbooks many times
as
 > well, and am getting an understanding on the tube process.  However,
 > assembling a project that I know will perform seems to help ease the
mental
 > anguish and promote an understanding of what I am doing.
 >
 > 5)  I've got two of John F's small toroids (2 by 6?).  Will I need
something
 > bigger?
 >
 > 6)  I have to ask:  How much spark can I expect with a durable design?
 >
 > Thanks for any info,
 >
 > John Richardson
 >
 >
 >