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Re: My VTTC fun begins...



Original poster: "Steve Ward" <steve.ward@xxxxxxxxx>

Brett,

The 2k should work.  It might not be optimal, but it will oscillate.
You can try maybe a larger capacitor on the grid leak too, but this
requires more current from the feedback winding.  The resistance there
isnt really super critical anyway, i found that on some days 5k worked
best, and on other days 10k worked best.  Usually the difference was
pretty small.  2k is a little low, but will get you going.

Steve

On 1/20/07, Tesla list <tesla@xxxxxxxxxx> wrote:
Original poster: Brett Miller <brmtesla2@xxxxxxxxx>


--- Tesla list <tesla@xxxxxxxxxx> wrote:

 > Original poster: "Steve Ward" <steve.ward@xxxxxxxxx>
 >
 > Glad to see you now have the ball rolling along on
 > the tube coil
 > project.  You have a nice collection of tubes to
 > work with.  I suggest
 > using the 833 over the 813 and 304 since the 813 is
 > a tetrode (or
 > pentode?) and the 304 is very fragile from my
 > experience (but quite a
 > work-horse for its size!).  Feel free to direct any
 > questions at me if
 > there is anything in particular.
 >
 > Im still waiting to build something with the 833Cs
 > that i have, but i
 > just cant seem to find the time (ive been saying
 > this for years it
 > seems).
 >
 > Steve

Steve,

Yeah, I know what you mean about finding the time...I
had this thing mothballed for about two years and was
just busy with so many other things.   It's all go
now, not much longer, just need to work on that base,
get the grid leak resistor(s), and wind the primary
and grid leak coil.  Of course, my ham radio buddy Dan
has gotten interested in tesla coils, and that does a
lot to bolster the excitement, having someone locally
to talk to and trade components with...Dan and I are
both good at scrounging and we often visit hamfests
together.

As far as which tubes to try first...I was already
planning on replicating your specs for a single 833A
system.  It seemed like the best choice for my first
VTTC since there is so much info out there, plus it
was beefy enough to handle my larger MOTs.  Later on,
I would like to branch out and see what I can do with
some of the rarer tubes we've scraped up around here.
I would like to run on filtered DC eventually, plus of
course staccato, and even use some smaller tubes in a
high frequency TC.

I actually have two 100W 1K power resistors
(originally purchased for a Terry Filter).  I could
put those in series, but wouldn't 2K Ohm at 100W be to
small for the grid leak resistance on my 833A?  It
would tend to run the tube too hot woudln't it?  Do
you think it would be safe for short runs, just to get
my feet wet?

-Brett



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