OLTC stands for Off-Line Tesla Coil, “invented by famous American coiler Terry Fritz”, his FAQ says, and it was nearly called the Fritz Generator. It is a classical coil with a solid-state switch in place of the spark gap and the supply straight off the wall, with no HV transformer, a direct evolution of the DC Tesla coil. His own sketch draws the three in a column. The Mini OLTC schematic is dated 16 Jan 2003: a 555 timer, one 1200 V IGBT where the gap would be, a primary of two turns of zip cord, about 100 W at 400 bps. First light came in the summer. It gave 7.5 in to a ground rod at 800 to 1000 bps, and 8.5 in on a half-wave supply at 1200 bps, on new International Rectifier IRG4PF50WDs after the first IGBTs died. “One of the first OLTCs,” he writes. The FAQ already carries the edit that ended the branch, about Jimmy Hynes' DRSSTC, 66 in at about 1.1 kW, “better than any OLTC to date.”
Schematics and photos
photo: the finished Mini OLTC 
sketch: classical coil, DC coil, OLTC, in his hand 
schematic: Mini OLTC, 16 Jan 2003 
photo: the controller box 
photo: a burst at 1200 bps 
photo: the spark, close 
photo: the IGBTs, before
Sources
- scopeboy.com: OLTC FAQ 1.0
- scopeboy.com: What's Tesla Three going to be? (the concept)
- scopeboy.com: Tesla Three lives (first light)
- scopeboy.com: the finished OLTC
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.