Tag Archives: Tubes

IEEE Spectrum: “The 11 Greatest Vacuum Tubes You’ve Never Heard Of”

Inside a transmitter at the Edward R. Murrow Transmitting Station.

Many thanks to SWLing Post contributor, Ed, who writes:

Hi Thomas, SWLing Post readers who are fans of tube radios might enjoy reading about “The 11 Greatest Vacuum Tubes You’ve Never Heard Of” in this IEEE Spectrum article. While only a few of them have been used in radio and audio applications, they’re all weird and amazing!

(Source: IEEE Spectrum)

In an age propped up by quintillions of solid-state devices, should you even care about vacuum tubes? You definitely should! For richness, drama, and sheer brilliance, few technological timelines can match the 116-year (and counting) history of the vacuum tube. To prove it, I’ve assembled a list of vacuum devices that over the past 60 or 70 years inarguably changed the world.

And just for good measure, you’ll also find here a few tubes that are too unique, cool, or weird to languish in obscurity.

Of course, anytime anyone offers up a list of anything—the comfiest trail-running shoes, the most authentic Italian restaurants in Cleveland, movies that are better than the book they’re based on—someone else is bound to weigh in and either object or amplify. So, to state the obvious: This is my list of vacuum tubes. But I’d love to read yours. Feel free to add it in the comments section at the end of this article.

My list isn’t meant to be comprehensive. Here you’ll find no gas-filled glassware like Nixie tubes or thyratrons, no “uber high” pulsed-power microwave devices, no cathode-ray display tubes. I intentionally left out well-known tubes, such as satellite traveling-wave tubes and microwave-oven magnetrons. And I’ve pretty much stuck with radio-frequency tubes, so I’m ignoring the vast panoply of audio-frequency tubes—with one notable exception.

But even within the parameters I’ve chosen, there are so many amazing devices that it was rather hard to pick just eleven of them. So here’s my take, in no particular order, on some tubes that made a difference.[]

Thank you for the tip, Ed. Brilliant article!

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Tubes and Valves: Dan’s research uncovers three vintage films

Hammarlund-SP-600

Many thanks to SWLing Post contributor, DanH, who writes:

I have been working on my Hammarlund SP600-JX-21 for the last two weeks. Results of the filter cap replacement were encouraging. I’m going after an AVC issue that is probably capacitor-related as well before doing a re-alignment with the signal generator.

All of this activity has turned my attention toward vacuum tubes. I found three vintage industrial films online that caught my interest…

The Mullard Radio Valve Company produced The Blackburn Story in 1962. The film was shot at what must have been close the peak of vacuum tube mass production. This presentation is unique in its finely detailed documentation of miniature tube construction. The hand labor required to build some of these tubes is incredible, considering it is a mass production operation. A surprising degree of automation is present for manufacture of some of the more popular tube types. The video resolution is not the best but I found myself ignoring this limitation after the film got underway. I have a few Mullard tubes in my tube boxes.

Click here to view on YouTube.

Western Electric presents A Modern Aladdin’s Lamp (1940). This look at the electron tube is hosted by none other than Lowell Thomas. From the age of four pin and octal base tubes animation shows how tubes work.

Click here to view on YouTube.

Electronics at Work (1943) is a WWII offering by Westinghouse. The description of vacuum tube technology is a little more detailed and again animation is employed for visual impact. A variety of vacuum tube applications in industry and the military are shown from curing plywood to producing X-rays. The excellent animation was contributed by Famous Studios (when they weren’t doing the wartime Popeye cartoons).

Click here to view on YouTube.

Wow–thanks for sharing these excellent videos, Dan!

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