Thursday, August 30, 2012


And in computers, yet? That's the report, though they're not going to look very much like the 6SN7s in Grandpa's flip-flops; nuvistors would look like skyscrapers beside them. Still and all, tubes. Who would've thought?


  1. Sweet! But they run on 1 volt? Pooh. The inherent risk in working with 400VDC power supplies was half the fun of using tube gear!

  2. I was reading an old electronics book from the 1920's and the way they described the workings of tubes was fascinating.

  3. Am remembering that my first job in computers was (in 1962) mopping and buffing the floor inside the computer. Giant, three story building-sized Air Force computer with rack beside rack beside rack of 6146s.

    Later, was assigned to early digital gear which used three 12AU7s to make a flip-flop. And a handful of 1N198 diodes that couldn't stand up to the heat in the racks.

    I don't miss the good old days as much as I miss being young enough to think I was having fun.

    Answering your question, not me.

  4. :) Indeed, Notagin -- one of my faves, resurrected decades later for transistors by Horowitz an Hill in "The Art Of Electronics," was the Tube Man, who reads grid voltage and works a Venetian blind (the grid) in the electron path between cathode and plate, thus varying plate current proportionally to grid voltage. It is an image that stuck with me -- and imagine how busy the poor fellow is in a multi-grid frequency converter tube!

    Dave H: sacrifices must be made. Preferably not human ones. While I agree that the plate voltage is part of the challenge, the number of hams lost in the 1930s from a too-casual approach to safety is pretty saddening. On the positive side, ARRL's "Switch to safety!" campaign had an immediate good effect, as did low-key efforts at publications like "Radio" magazine, which started paying more attention to not using exposed connections for HV in projects, etc. Most modern engineers and techs would have to do a lot of relearning in order to work with HV (50V or more) again.

  5. Indeed. I worked with a newly minted EE some years ago who was more than a little leery of the power we were pushing around the lab. (We made 3 phase power meters, commonly tested at 1800 watts.) I was giving him the nickel tour on his first day and he interrupted to say, "Kilovolts? Megawatts? Man wasn't mean to deal with such things. The most power we ever handled in school was a couple hundred milliwatts."

    I agree high voltage needs to be kept in its place. But knowing it's there and will bite you if you disrespect it still adds a little spice.

  6. Not a fan of HV mostly because I've been bit and hit in the commercial spaces.

    But I Still use tubes and have no problem with it to about 250V. though I've
    had a bunch of fun with space charge tubes (typically 12V plate) and smaller
    tubes at voltages in the 12 to 67V range. Old 1U4, and 3S6 and the like are fun
    and I've built very nice receivers using them and not just regens. For higher
    performance Neuvistors and some of the other submini kin in the t1-3/4 bulbs make
    for higher performance radios without going over 100V.

    Good fun and lots of them to still be had cheap.


  7. If only it meant that the GE 8950 PA tube in the radio I bought against your advice was easier to locate ...