“Late last year I tackled the reliability problems with the original SSTC design,” the page says. That section was already there when the Internet Archive first saw the page in October 2001, so the rebuild dates from 2000. His change log puts the progress report on 31 Oct 2000 and the 18 in pictures on 9 Dec 2000. It is a full H bridge of four STW15NB50s on 240 V mains, half-wave rectified with no reservoir capacitor, drawing about 5 A RMS. The resonator is 3.5 by 16 in under a 6 by 1.5 in toroid, with a 19-turn primary link-coupled over the bottom third (k about 0.40) at a nominal 350 kHz. It makes 4800 W peak envelope for about 1200 W in, with 22 A peak in the primary. The drive frequency is swept over the mains cycle to follow the resonator as the spark grows. He calls this very crude, but it keeps the sparks from snubbing themselves out. Sparks average 14 in, with the odd hit at 18. The driver is a 6 by 4 in board on a heatsink with its own 15 V transformer, and everything else runs off the mains. On smoothed DC the same coil makes a 9 in flame at 1500 W, and white balls of burning aluminium come off the toroid, caught in a frame sequence.
Schematics and photos
photo: the H-bridge coil at work 
photo: the driver board, annotated by its builder 
photo: the 9 in flame on smoothed DC, 1500 W 
photo: a white ball of burning aluminium leaving the toroid 
frame sequence: the balls
Sources
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.