Make your own vacuum tubes. Easy--if you have the special tooling.

January 4, 2008 11:11 AM

Making your own transistor is probably beyond the abilities of a dedicated hobbyist. However, making simple triode vacuum tubes is practical. Many hobbyists have done so over the years. In this video, French ham-radio operator Claude Paillard shows you how. HIs model is the WWI-era type TM of 1915. (and btw, 2007 was the 100th anniversary of electronics, since de Forest made his first vacuum tube in 1907.)
posted by metasonix (22 comments total)

Damnit. Nobody told me that the French language was a prerequisite for building vacuum tubes.

Now, where did I put those Rosetta Stone discs?
posted by grumpy at 11:35 AM on January 4, 2008

Any hams in Mefiland?

I have long envisioned a convoluted Mefi posting system that involves ham, pigeons, cootiecatchers, catscradles and stopmotion that'd take a couple or more of us to implement.

No equipment for atleast a year more. This makes sushi sad. Hmmm.
posted by sushiwiththejury at 11:45 AM on January 4, 2008

I still have my license but haven't owned equipment in years. I've been tempted to reread the handbook so I can get active again but it's not a high priority.

I'd love to roll my own tubes though, especially if I could make a Nixie Clock.
posted by drezdn at 12:09 PM on January 4, 2008

@sushiwiththejury: I am, although I'm only a Technician, so no HF for me.

I have the study book for General (and actually passed the written test for it once, but my CSEC expired before they got rid of the Morse requirement, which I could never pass) and feel like once I get that, things will get more interesting. There's some cool stuff going on VHF, but what's always interested me are the DX-worthy digital modes on HF.

Anyway, back on topic: that video is incredible. I wonder where he got all the tooling? If it's all homebuilt, some of it is even more impressive than the vacuum tubes themselves. He even has what looks like an injection-molding machine for making the plastic bases.

This guy is a "hobbyist" in the same way that somebody in the Olympics is an "amateur" athlete.
posted by Kadin2048 at 12:33 PM on January 4, 2008

My dad's big into HAM radio. I'll send this post his way.

Also did anyone else notice that the color scheme of the site in the second link is remarkably similar to that of MeFi?
posted by CitrusFreak12 at 12:47 PM on January 4, 2008

Nice video :) No wonder they cost north of $100 apiece!

I believe Tom Edison was the first to document that a stream of electrons would "boil" off of a hot filament and stream towards a collector plate, and maybe it was deForest who first discovered that a grid with a negative charge would repel and therefore modulate the electron stream.

Anyway, I once duplicated the experiment of heating a filament in an oxygen-depleted environment and measuring the current collected on a plate. The filament was stolen from a burned lightbulb, and the envelope was a smallish relish jar with the electronics mounted on the lid, and the lid secured to a board. The oxygen was removed by burning some paper on the lid and quickly screwing the jar onto the lid; the burning continues til it goes out for lack of oxygen.

No amateur licence here, but I have been an electronics geek since about grade 6, turning pro at age 16.

Although I now pay the mortgage by doing programming, I've never completely stopped messing about with electronics. Besides repairing and rebuilding various household things in the last few years I've had a fling with hand-building regenerative radios, and building with microcontrollers.

I'm not impressed with Nixie-tube clocks. Maybe that's because I once had to use frequency-counters and digital meters with Nixie readouts... blecch. I think that PoV displays are much cooler.
posted by Artful Codger at 12:51 PM on January 4, 2008

W5GNF here.... I infest 80, 40, 20 mostly, don't do much CW at all. Collect Collins, military, boatanchors and the like.
posted by drhydro at 1:01 PM on January 4, 2008

Making your own vacuum tubes at home may be possible, but I wouldn't say practical...
posted by lalas at 1:55 PM on January 4, 2008

DeForest's patent.

A Taste of Tubes (pdf)

very cool post (and so too the Metasonix vacuum tube music synthesizers)
posted by caddis at 2:12 PM on January 4, 2008 [1 favorite has favorites]

In 1912, he (DeForest) developed a feedback circuit, which would increase the output of a radio transmitter and produce alternating current. He didn't see the worth of his discovery, though, and by the time he applied for a patent in 1915, it had already been patented by E. Howard Armstrong. De Forest sued, with legal action lasting until 1934. He won, but the radio industry always credited Armstrong with the invention

The suit against Armstrong was generously funded by ATT.

Armstrong also invented FM radio, which RCA managed to keep marginalized for about 30 years.

The gutted remains of ATT and RCA still litter the corporate landscape.
posted by hexatron at 4:25 PM on January 4, 2008

I mean
the gutted remains of ATT and RCA still litter the corporate landscape.
posted by hexatron at 4:27 PM on January 4, 2008

Oh I don't know, you 'might' be able to make your own transistor. Or maybe this will make things a little easier. But if you're looking for small and actually useful, best of luck to ya.
posted by ZaneJ. at 4:36 PM on January 4, 2008

That. Was. Awesome.

I noticed he did everything with his bare hands. Wonder if he dunks the guts in solvents before sealing it up to get the salts and organics off.
posted by ZenMasterThis at 4:37 PM on January 4, 2008

We made our own diodes in high school physics, and making a transistor would just be adding another junction on the wafer. It would probably be pretty lossy, though.

I don't remember all the details (this was 35 years ago), but we started with a silicon wafer, put a mixture of something on top and baked it.
posted by rfs at 6:25 PM on January 4, 2008

That was a most elegantly done DIY video, all the steps were represented (except tool construction) with little redundancy or wasted time. I suspect 99.99% of the population would take at least a thousand tries to be able to consistently produce working tubes using his methods though. Most of us would just give up.
posted by BrotherCaine at 8:00 PM on January 4, 2008

> btw, 2007 was the 100th anniversary of electronics, since de Forest
> made his first vacuum tube in 1907

hmm. What about the battery, dated to a couple centuries AD? Or Coulomb's description of the relationship between positive & negative charges in the 1700's? Or Kirchoff's description of the laws of curent in circuits in 1845? Or Cavendish's (1781) and Ohm's (1827) descriptions of current, voltage, and resistance in circuits?

"The 100th anniversary of vacuum tubes", sure. But of electronics? Nope.
posted by spincycle at 9:44 PM on January 4, 2008

Wow...the video was amazing...so many skills required. I remember when nearly every supermarket would have a tube testing station. (Getting old.)
posted by rmmcclay at 9:46 PM on January 4, 2008

Scientific American's Amateur Scientist once had a piece on making transistors. I'd say probably somewhere in 1975-1985.
posted by neuron at 10:05 PM on January 4, 2008

It's surprisingly easy to make your own solid-state diode - otherwise known as a cat's whisker. Get a lump of lead ore (galena), or at a pinch coal or a rusty razor blade edge, make a good contact with one side then gently probe the surface with a fine wire. (More details here or many other places online). With a coil of wire, a capacitor (which can be anything that approximates to two metal sheets separated by an insulator), an aerial wire and some form of headphone (which you can also make yourself, if you absolutely have to), you've got a complete working AM radio. Very popular in prisoner of war camps, foxholes and other places where Radio Shack or Maplin don't deliver.

And yes, I'm one of 'em radio amateurs. There's never been a better time: I've got a reasonably complete multimode 2-30MHz plus VHF and UHF transceiver backpack set-up that I can get just about anywhere under my own steam, and it cost around $800 new. When I was first licenced in the early 80s, the closest you could get was a military manpack that didn't do half of that, weighed five times as much and cost ten times plus. Add something like the Eee to cope with some of the really rather fab digital modes (TV, digital voice, long-distance low-bandwidth PSK) for another $300 or so, and it's rather more fun that faffing around on the intertubes trying to work out why this or that video driver doesn't work. That's before playing with satellites, location-based services, moonbounce (that's where you say "hello" into your microphone, and hear your voice come back three seconds later because it's bounced. Off the friggin' moon.) or any of the other delicious niches.

On the downside, we've been at the bottom of the sunspot cycle for a while now, and it's not getting much better. A quiet sun means a whole class of simple, effective, very long distance contacts goes away - trans-global comms with stuff you can build into an Altoid's tin. Looks like the next cycle might be a wash-out too, so that's potentially eleven years hanging about...
posted by Devonian at 3:01 PM on January 5, 2008

spincycle :hmm. What about the battery, dated to a couple centuries AD? Or Coulomb's description of the relationship between positive & negative charges in the 1700's? Or Kirchoff's description of the laws of curent in circuits in 1845? Or Cavendish's (1781) and Ohm's (1827) descriptions of current, voltage, and resistance in circuits?

"The 100th anniversary of vacuum tubes", sure. But of electronics? Nope.

As I understand it- the battery, the findings of Coulomb, Kirchoff, Ohm, Ampere, Cavendish and the like apply to the understanding of electricity, and the applications that were based on those, like lighting, the telegraph and even the telephone, made passive use of electricity; in other words, electricity was made chemically (batteries) or generated (in the case of telephones, generated from sound), then just expended into a load (a light bulb, a telephone receiver).

It wasn't till the invention of the vacuum tube that an electrical signal could be amplified and processed, which greatly expanded what could be done with electricity. The tube made possible/practical things like radio transmission and reception, audio amplification and optical encoding/decoding of sound (necessary for sound in movies), etc etc.

I believe the term electronics refers to the subset of electricity where information is actively created and/or processed as electrical signals, which wasn't possible till the invention of the vacuum tube... so yes it IS the the 100th anniversary of electronics.
posted by Artful Codger at 8:59 AM on January 6, 2008 [2 favorites has favorites]

More info on foxhole radios: (link, link)

I built one as a kid... it worked. I wonder if people can get ahold of the old-school double-edged razor-blades these days...
posted by Artful Codger at 9:04 AM on January 6, 2008

Can't believe I missed this post!

spincycle: "The 100th anniversary of vacuum tubes", sure. But of electronics? Nope.

Artful Codger: I believe the term electronics refers to the subset of electricity where information is actively created and/or processed as electrical signals, which wasn't possible till the invention of the vacuum tube...

I have to agree with Artful Codger, even though introductory circuits courses sometimes get the term electronics attached to them.. Then there is active vs. passive :)
posted by Chuckles at 11:48 AM on February 3, 2008