Original poster: FutureT-at-aol-dot-com In a message dated 7/13/04 7:07:50 PM Eastern Daylight Time, tesla-at-pupman-dot-com writes: >Basically any triode or pentode vacuum tube of great enough >power handling capability can be used in a tube coil. > >John > Correction: I meant to say triode or tetrode. Of course the pentode can work too. John