A three-coil DRSSTC, to stop the output arcing back onto the primary and strike rail. Later the test bed for UD2: the phase-lead driver was first run on this coil's successor, the Mark I magnifier, in October 2009.
Schematics and photos
lower deck: bus caps, heatsink and driver board 
DRSSTC magnifier 1 · Driver 
DRSSTC magnifier 1 · Resonator 
DRSSTC magnifier 1 · Setup 
DRSSTC magnifier 1 · Base 3 
DRSSTC magnifier 1 · Base 4 
DRSSTC magnifier 1 · Base 5 
DRSSTC magnifier 1 · Currenttransformer 
DRSSTC magnifier 1 · Driver 01 
DRSSTC magnifier 1 · Primary 01 
DRSSTC magnifier 1 · Resonator 01 
DRSSTC magnifier 1 · Resstand 
DRSSTC magnifier 1 · Spark 1 
DRSSTC magnifier 1 · Spark 2
Sources
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.