Woodelf wrote: Tubes, transformers, chokes. Some ham and audio stuff, but one of my latest projects does digital logic with several dozen 6SN7's. No, it's not actually a "computer" in that it's not programmable but my next thoughts are turning to that arena. The first programmable stuff I might do would end up being plugboard programming, most likely. I've recently been playing with heptodes as logic gates (and gotten many 7036's with IBM labels from AES. They're dirt cheap, and if I do it right each will replace 1 to 3 6SN7's!) Tim.