If you want to build your own vacuum tubes, whether amplifying, Nixie or cathode-ray, you’re going to need a vacuum. It’s in the name, after all. For a few thousand bucks, you can probably pick up a used turbo-molecular pump. But how did they make high vacuums back in the day? How did Edison evacuate his light bulbs?
Strangely enough, you could do worse than turn to YouTube for the answer: [Cody] demonstrates building a Sprengel vacuum pump (video embedded below). As tipster [BrightBlueJim] wrote us, this project has everything: high vacuum, home-made torch glassware, and large quantities of toxic heavy metals. (Somehow [Jim] missed out on the high-voltage from the static electricity generated by sliding mercury down glass tubes for days on end.)



So given a disaffection with the ubiquity of Nixies you might think that no Nixie project could rekindle that excitement. That might have been true, until the videos below the break came our way. [Tobias Bartusch] has made his own Nixie tube, and instead of numerals it contains 



For the display, he’s using eight big vintage Burroughs B7971 Nixie Tubes. These aren’t easy to source, and current prices hover around $100 each if you can find them. The 170V DC needed to run each tube comes from a set of six