[TCML] TC vs "Plasma Speaker" ?

[b alex pettit jr <a_pettit_jr@xxxxxxxxx>]

Hello All,
 
I recently purchased a 'plasma speaker' kit from Ebay. It works okay,
but I was hoping I could top load it with a small toroid and get
longer sparks - not so.  
 
The intent was to build a 'safe'   Tesla Coil for classroom demonstrations 
of electrical resonance to compare to mechanical resonance for my 
mechanical engineering students -  the sound input not of  real value for this
purpose.
 
The class E amp has few parts : a 4046 PLL drives a complementary transistor
pair to a single irfp450 MOSFET. The sparks are at best 3/4" long from a banana jack
( intended to  hold the Toroid ). Anything else added to the discharge electrode
pretty much kills the sparks.  The coil gets warm, but does not seem to radiate
much energy in the form of a visible discharge.
 
I built a  power supply with selectable output voltages .The unit draws 
44W at 22vdc, 
84W at 35vdc, and ( although no visible change in spark size ),
183W at 43vdc.... the MOSFET gets hot quickly on this setting !
 
The coil is 2" dia, 7.5" long, #32 AWG - intended to resonate at 1 MHz - this was verified
by JavaTC.  Calculations show the top loading via the 4" x 1" toroid detunes the
system to 800 KHz.
 
Any suggestions as what to change or adjust to allow long sparks ( any sparks ! )
 from the toriod would be Most Welcomed !
 
Thanks,
Alex
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