The Bendix G-15 Runs 75,000 Lines Of Code

There’s a Blue Bendix in Texas, and thanks to [Usagi Electric] it’s the oldest operating computer in North America.  The Bendix G-15, a vacuum tube computer originally released in 1956,…

Cataract Surgery For An Old TV

TVs used to be round, and the GE M935AWL is a great example of that. [bandersentv] found one of these ancient sets, but found it had a “cataract”—a large ugly discoloration on the tube.…

BNCs For An Old Instrument

Back in the summer our eye was caught by [Jazzy Jane]’s new signal generator, or perhaps we should say her new-to-her signal generator. It’s an Advance E1 from around 1950, and it was p…

A Digital Replacement For Your Magic Eye

Magic Eye tubes were popular as tuning guides on old-school radio gear. However, the tubes, the 6U5 model in particular, have become rare and remarkably hard to come by of late. When the supply dri…

Making A Solid State 6AK8 Tube

[M Caldeira] had a project in mind: replacing a common vacuum tube with a solid-state equivalent. The tube in question was an EABC80 or 6AK8 triple diode triode. The key was identifying a high-volt…

Plight Of The Lowly Numitron Tube

In the 60’s and 70’s there were many ways to display numeric data. Nixie tubes, Vacuum Florescent Displays (VFD), micro projection systems, you name it. All of them had advantages and d…

A Tube Tester Laid Bare

There’s still a mystique around vacuum tubes long after they were rendered obsolete by solid state devices, and many continue to experiment with them. They can be bought new, but most of us s…

A Low Voltage Tube Makes For A Handy Preamplifier

When most people think of tube circuits, the first thing that comes to mind is often the use of high-voltage power supplies. It wasn’t a given for tube circuits, though, as a range of low-vol…

Roll Your Own Simple Tube Tester

You can easily get carried away when trying to test things. For example, if you want to know if your car is working, you could measure the timing of the ignition and put the car on a dynamometer. O…

Tube Amplifier Uses Low Voltage, Sips Battery

Much like vinyl records, tube amplifiers are still prized for their perceived sound qualities, even though both technologies have been largely replaced otherwise. The major drawback to designing ar…

Single Photon Detection With Photomultipliers

Unless you are an audiophile, you likely think of tubes as mostly relegated to people who work on old technology. However, photomultiplier tubes are still useful compared to more modern sensors, an…

Everything You Wanted To See About Restoring A 1956 Radio

Ever wanted a good, good look at the insides of a 1950s radio, along with fantastic commentary on the internals and the purpose of various components? Then don’t miss [Adam Wilson]’s re…

Vintage Tube Tester Teardown

[Mr. Carlson] has an old-style 1940-era radio tube tester, the kind that used to inhabit grocery and drug stores. It is in amazing condition and he was kind enough to tear it down for us. The teste…

Reactive Load For Amplifiers Teaches Lessons About Inductors

The sound produced by any given electric guitar is shaped not just by the instrument itself but by the amplifiers chosen to make that sound audible. Plenty of musicians swear by the warm sound of a…

Hackaday Prize 2022: Glass Tube Solar Thermionic Converters

Typically, if you want to convert solar energy into electrical energy, you use either photovoltaic (PV) cells, or you use the sunlight to create steam to turn a turbine. Both of these methods are w…