My 811a Vacuum Tube Tesla Coil

This is a video of my dual 811a power triode Vacuum Tube Tesla Coil based on Steve Ward's VTTC1 design.  The secondary is a 3 inch PVC pipe wound with 850 turns of 24 awg magnet wire.  The primary coil is 20 turns, with a 1000pf tank capacitor.  Currently I am achieving 6-7" sparks, with minimal tuning and adjusting.