Push-pull Tube coil First Light, Plate transformer.

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

Hi All!
 
  Got my VTTC working beautifully in push-pull.  An O-scope with a simple
antenna does a million times better for tuning it.  While the tuning isn't
"dead on", it's within a few hundred hertz per side of the primary.  The whole
setup looks difficult to build and wire, but it's not nearly as difficult as
you'd expect, and it has a distinct elegance to it.    I haven't run the setup
over a few hundred watt, due to plate transformer constraints.  
 
   Full-wave rectified DC, fed to the middle of the primary, tubes and tap for
the MMC's on the far ends of the primary.  Grid leak connects to the middle of
the grid windings, and the ends each go to a tube.  Simple!  Working with the
coil (which puts off a *TON* of ozone) is easy, and any mis-tuning in the
primary is easily seen on the scope, and even better, heard!  When the primary
is out of tune, you can hear a high-pitched squall from the output.   Putting
capacitors across the DC supply did a lot to boost output, but it also rasied
current consumption on the mains side more than I liked. Running well-tuned,
the output is a steady humming hiss rather than the not-so-subtle 60hz hum of
my voltage-doubled setup.   It works, is simple, and best of all, works
*GOOD!*  
 
 Biggest problem I have at the moment is finding a suitable core to wind my
plate tranny on.  I'm needing something in the 5-6kva range.  An old arc welder
would be awesome, assuming I could get the core apart without ruining it.  I
want to run the tranny off 240v and get 2500v (2800v by tapping the primary). 
With a center-tapped design that means I should have 5.2:1 turns ratio for each
secondary.  I have all the parts for a suitable winding jig, I just need to rig
up a turns counter and find a core.  I'm wanting in the 5-6kva range from it, I
can ballast it externally if needed.  
 
  For controlling the grids externally, can I wind a step-up transformer on set
of ferrite clamshells I scrounged from an old TV?  That way I can feed a
modulated signal to the primary on the tranny and get corresponding output high
enough to switch the tubes?  Does the whole transformer need to all be on 1
ferrite half, or can I wind them on separate halves and use the supplied clips
to clamp the cores together?  Thanks!!
 
                                                                           
                Shad