Hello Coilers, Another tube for concideration in building VTTC's is the 304TH which is actually four triodes within one glass envelope. If I remember right, the filaments take 5 volts at 25 amps and the tube is good for about a kilowatt up to around 10 mHz. 73, Weazle, VE3EAR/VE3WZL Listening: 147.030+ and 442.075+ E-mail: weazle-at-hurontel.on.ca or ve3ear-at-rac.ca Web site: www.hurontel.on.ca/~weazle