Plasma tweeter troubles (I need a little help from the tube guys here.)

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Original poster: "Tom Stathes" <newphreak_16-at-yahoo-dot-com> 

Hello all,

I have just built the plasmatweeter described on
http://plasmatweeter.de

   It uses a Pl519, as an oscilator to drive a coil -at-
28mhz and produce a plasma discharge.
I am having 2 problems with this circuit.
The first is that the voltage labeled 100v in the AV
section is reading about 180-190.
The other is that the pl519 heats up and starts to
glow after a few min even when the flame pot is turned
down low.  I used a pot going to ground to ajust the
180v down to 100v, but the Pl519 heats up way too much
still and i dont know how to stop this.
Could my coil not have the correct frequency causing
it to draw too much power to drive?

Any help would be greatly appreciated.
Thanks
Tom