Vladimiro Mazzilli kept a gallery on the Tesla list's own pages at pupman.com, and his captions describe the coil. It is a self-tuning resonant MOSFET coil: a half bridge of four IRF460s, sixty-four 3.3 nF 2 kV MKP capacitors “for resonance”, about 200 kHz, the mains envelope selectable between half and full wave, and forced-air cooling. The capacitors are the blue block in the photograph, wired to the primary. That is a tank on a transistor coil, years before the class had a name. A gallery map of his pages archived on 8 Feb 1999 already lists photographs by these file names, so the coil is at least that old. His schematic is a PDF made on 13 Feb 2001, titled Solid State Semiconductor Tesla Coil, and it is drawn like an electronic ballast. A DB3 diac starts it. There are four IRFP460s and a feedback transformer with a one-turn winding in the tank circuit. The primary is 18 turns of litz on a 130 mm form, in series with the bank, and the secondary is 2000 turns. A switch selects between 50 and 100 Hz, half- or full-wave mains. There is only 0.47 µF on the bus, so the envelope follows the mains. A smaller version with a pluggable resonator ran on full-wave mains only.
It does not show the long spark. The photographs show brush discharge off a small resonator, and nothing he wrote describes what the half-wave envelope did to the spark. That observation is why Burnett's page is on these trees. Dan McCauley, in the 2004 thread on the list, passed on Jan Wagner's word that Mazzilli had a resonant primary with an MMC “back in 1997 or so”. That is second-hand. Liviu Vasiliu wrote in 2010 that it was the first DRSSTC he ever knew, with tuned tank and primary feedback, from early 2001, long before Hynes and Ward. No documented line runs from it to Hynes, so it stands beside the root, not above it.
Schematics and photos
photo: the coil 
photo: the bank of 64 MKP capacitors at the primary 
photo: the half bridge, heatsinks and fan 
photo: brush discharge off a bar terminal
Sources
- pupman.com: Mazzilli, the mosfet coil and its caption
- pupman.com: his schematic (PDF, made 13 Feb 2001)
- Internet Archive: his gallery map, 8 Feb 1999 (the photographs listed)
- Internet Archive: the caption page, 18 Feb 2001
- pupman.com: Dan McCauley, 14 Jun 2004 (Wagner on Mazzilli, second-hand)
- pupman.com: Liviu Vasiliu, Oct 2010 (his recollection)
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.