Re: Mini VTTC--Possible tubes?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>

Hi Steve, All
         I used a MOT for the filament tranny on my single and dual 833A 
VTTC.  I chiseled off the fine wire with a hammer and chisel, then wound a 
handfull of turns on it with 20ga wire till I got the correct number of 
turns on it for 10v.  I cut the 20ga off and wound it with 12ga THHN wire, 
2 wires in parallel.  Don't bother with a centertap ground, it's not worth 
the trouble, just ground 1 leg of the 10v windings.

   Don't worry about saturation with a MOT, it's not an issue while using 
it as a filament tranny.  It'll only be seeing about 200w or so.  And even 
if it did saturate, it wouldn't overcurrent the tubes, they're a resistive 
load, so they only pull as much as they need.
   For my quad 833 I used 1/8" copper tubing on an old NST core and the old 
NST primary (12/30).  Works beautiful.
Here's some pics of the quad 833 VTTC in tests, also shows the filament tranny.
http://sundog.timeship-dot-net/HV/cw_prjct/cw_prjct.htm

Caio!

At 08:04 AM 3/7/02 -0700, you wrote:
>Original poster: "Steve White by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><slwhite-at-zeus.ia-dot-net>
>
>I am planning on building a dual 833A VTTC eventually and I am also facing
>the filament tranformer issue. The two 833As will need 20 amps at 10 volts
>for filament power, not exactly a common transformer. My plan is to build my
>own filament transformer. I will use one of my many MOTs that I have lying
>around. I will remove the secondary windings and wind on 12 turns of
>suitable wire for the secondary. Since the MOT core should handle at least 1
>KW without saturating, this seems like a good plan.  12 turns would be easy
>to wind.
>
>Steve: Coiling in Iowa
>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Wednesday, March 06, 2002 6:57 PM
>Subject: Re: Mini VTTC--Possible tubes?
>
>
> > Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>"
><evp-at-pacbell-dot-net>
> >
> > > > > Hi,
> > > > > I have decided to start a VTTC.I was wondering,what sorta tube is
> > > needed?I
> > > > > want the smallest and cheapest possible tube to start with.Can
>someone
> > > give
> > > > > me a list of possible tubes?Or what do i need to look for?
> > > > >
> > > > > Thanks so much,
> > > > > Matt
> >
> > In addition to traditional RF power tubes, almost ANY audio power or TV
> > sweep tube capable of 10 or 20 watts output will work just fine, so you
> > have a wide selection of potential sources.  A lot of these now go for
> > incredible prices because of the interest of audiophiles (audio
> > snobs/nuts to me) who debate at great lengths over the relative merits
> > of "triode" sounds compared to "pentode sounds", etc. etc.  You can even
> > buy HI FI coupling capacitors and resistors to improve your tone
> > quality.  (If you are a true believer!)  Look around the web and you'll
> > find a lot of guys selling suitable tubes, some at quite reasonable
> > prices.  Power triodes are easier to use than power tetrodes or
> > pentodes, but somewhat pricier now because of the supposed superiority
> > of "the triode sound".
> >
> > One source of greatly over priced tubes is Vacuum Tube Alley
> > (www.vacuumtube-dot-com).  Go there to see what kind of tubes are generally
> > available, then look at their exhorbitant prices and have a good laugh.
> > Anything else will be cheaper.  A much better source is Antique
> > Electronic Supply in Tempe, Arizona.  Their web site is
> > www.tubesandmore-dot-com.  Very reliable outfit, prices reasonable even
> > though you can do better.  Finally, swap meets are a great source of
> > higher power tubes, but you have to be somewhat knowledgeable (sp?) in
> > your shopping.
> >
> > Remember that the VTTC needs more than just the tube(s).  It also needs
> > a high voltage power supply of some sort and, just as hard to find these
> > days, a suitable filament transformer.
> >
> > I have some other tube URL's which I'll forward to anyone who wants to
> > send me an email to:
> >
> > evp2-at-earthlink-dot-net
> >
> > Ed
> >
> >
> >
> >

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Shad (Sundog)
G-2 #1203
"Ever stop to think, and forget to start again?"
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