Hi, I'm building a vacuum tube tesla coil using four 811A's in parallel. How can I calculate the value of grid-leak resistor? I'm looking for "bathtub" or "doorknob" -type mica or ceramic RF capacitors. Where can I get them? I'm also looking for threaded ceramic insulator about 1-3/8" long and four standoffs about 1-1/2" long. Regards, Tero Ranta Vacuum Tube Tesla Coil Page: http://www.icenet.fi/~dixie/