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Hand-Made Vacuum Tubes
Posted by
kdawson
on Tue Jan 08, 2008 06:19 PM
from the doesn't-suck dept.
from the doesn't-suck dept.
djmoore writes "Over at Make Magazine, watch this video of a French amateur radio operator making and testing his own vacuum tubes. It looks like he built much of his own equipment as well. The Make poster notes: 'I love the ease with which he performs these rather high-end skills (like glass forming), the gestural flourishes (like it's hand magic), and the Zelig-esque soundtrack.'"
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reason (Score:5, Funny)
This was covered in Make Magazine, primarily because Nature abhors a vacuum.
are you saying (Score:4, Funny)
Parent
Yeah, well (Score:5, Funny)
Parent
Re:"French amateur radio operator" (Score:5, Informative)
What is it with acting like foreign nationals are some sort of trained monkey? C'mon folks.
Anyway, here's a direct link to his site so you can skip the non-article at Make. Site includes much information (use the fish as needed), the streaming dailymotion vid, and a download link for those who can't see streams. Enjoy.
http://paillard.claude.free.fr/ [claude.free.fr]
Thanks Claude! That rocks.
Parent
thank you (Score:5, Insightful)
Parent
Re: (Score:2)
Re:"French amateur radio operator" (Score:5, Funny)
Parent
Re:"French amateur radio operator" (Score:5, Funny)
Freedom amateur radio operator...
There, fixed it for you.
Parent
Re:reason (Score:5, Informative)
Parent
Re:reason (Score:5, Funny)
Parent
Re: (Score:3, Insightful)
If it's gonna 'take over' the Internet, it should be an open standard. I should be able to build the Flash Player the same way I build Seamonkey.
The art of electronics (Score:5, Insightful)
Re:The art of electronics (Score:5, Interesting)
Parent
Re:The art of electronics (Score:4, Interesting)
However, if you're going to spend that much time, why not build a full size vehicle so you can actually drive it?
Parent
Re:The art of electronics (Score:5, Interesting)
Though with some people, this sort of thing can get just a bit _too_ obsessive:
http://www.sandia.gov/LabNews/LN02-13-98/cherry_story.html [sandia.gov]
'The switch mechanisms Kaczynski used were hand-made switches that he would spend weeks building...He machined his own screws.'
Parent
Re:The art of electronics (Score:5, Funny)
Many moons ago I was the "gofer" for our school's one act play. The lead character was going to use a prop broom as a crutch, so the teacher in charge told me to shorten the wooden screw-in handle of the broom. I cut the stick down, and spent the afternoon hand-carving a new screw thread into the bare wood that fit perfectly in the broom head. I was really proud of that carving. But the handle was still a few inches too tall, so the teacher told me to cut it shorter. And this time, he told me to just cut off the plain end. D'oh!
Parent
Re: (Score:3, Insightful)
We need this type of thing done in the classrooms (Score:5, Insightful)
Re: (Score:2, Insightful)
Re:We need this type of thing done in the classroo (Score:5, Informative)
The purpose of using vacuum tubes in a guitar amp is for the overdrive characteristics. When overdriven, solid state amplification circuitry clips the waveform to the voltage rails, resulting in a harsh sounding distortion due to the dissonant overtones.
A tube amp driven to distortion compresses the waveform rather than hard clipping. This results in a waveform rich in harmonic overtones - the classic distorted guitar sound.
Any person who is not tone deaf can tell the difference between solid state distortion and tube distortion. Please don't compare the basic principles of rock guitar with overpriced audiophile folly.
Parent
Re: (Score:3, Informative)
Especially when it's one of these [gibson.com] played through one of these [orangeamps.com].
Re: (Score:3, Informative)
Much of the overpriced is going away along with tube microphonics, gassy tubes, high voltage resistors, capacitors and high power consumption. With Digital Signal Processing DSP is rapidly providing 24 bit 40KHZ or higher modeling of the classic sounds without the problems and high cost. The overdrive curve of
Intelligent Distortion (ID) (Score:3, Funny)
Well that's only your theory. I however believe in "intelligent distortion" (ID) and that's what I teach my kids thank you very much.
Re:We need this type of thing done in the classroo (Score:4, Insightful)
Parent
It does not even need to be this complex (Score:3, Informative)
My kids and I built a crystal set and made a cats whisker diode for it using some brass sheet, wire and a lump of galena (from the mineral & crystal shop). Also made a diode with a rusty razor blade and another with a lump of silicon. These didn't work as well as shop germanium diodes, but they still worked. Made our own variable capacitors using paper and tin foil too.
You can even build simple amplifiers etc using tunnel diodes: http://home.earthlink.ne [earthlink.net]
Re:We need this type of thing done in the classroo (Score:3, Interesting)
Id like to see you make semiconductor based transistors in your basement.
Semiconductors never could have been made without (Score:5, Informative)
Once you get beyond the crude PN junction diode (like a galena crystal), making transistors and such requires ridiculously pure germanium and/or silicon. These materials are purified by a process called "zone refining" which uses induction heating to melt the semiconductor materials at incredibly high temperatures. Induction heating in turn requires many kilowatts of radio frequency power, which is exactly the type of application where vacuum tubes are still widely used even today.
Parent
Not just them. (Score:4, Interesting)
If you wanted to build some part of an embedded device that absolutely had to take some really ugly conditions, you could do a whole lot worse than to build that specific module using valves. Let's say you wanted to build a new module for the IIS, for example. The internal circuits can largely be protected, so conventional radiation-proof chips would be fine. However, if you wanted reliable computing elements that could be strapped to the outside of the pod, you've harsh conditions indeed. Lead-smothered rad-hardened silicon chips that can handle space tolerances and have their own heating elements would probably work. Lots of things that can go wrong, though. Complexity-wise and weight-wise you're probably not significantly better off than using thermionic valves with none of the extras.
Where else could valves be used? Easy. If the cathode and anode are deliberately mis-aligned, then one or more grids must be set to a value such that the directed power completes the circuit. If something goes wrong (too much power, something fails, whatever), then the beam is either not pushed at all or pushed far too far. In either case, you've an all-electronic circuit-breaker - ideal if you want to get rid of fuseboxes and mechanical trip-switches.
Parent
"Sometimes you need to reinvent the wheel... (Score:4, Insightful)
Parent
Re:We need this type of thing done in the classroo (Score:4, Informative)
You do get X-rays from tubes working at high voltages, but they are of pretty low energy in typical applications and probably don't make it out through the glass. TV tubes use leaded glass to reduce the X-radiation.
Parent
Re: (Score:3, Informative)
Re:We need this type of thing done in the classroo (Score:5, Insightful)
You can learn a hell of a lot from vacuum tubes! They are far easier to understand than transistors.
There's a reason why they're called "valves" in the UK. It's like a valve controlling a powerful stream of water; a small change on the valve leads to a very large change of current. That change in current can, in turn, control a much bigger valve that controls an even larger current.
In this case, the "valve" is a control grid (that spiral thing) surrounding the cathode (the thin hot wire in the middle). The big cylinder is the "plate". The cathode itself has a cloud of electrons around it (because it's hot), and a small signal on the grid controls how much of that can scoot across to the plate (which is positively charged due to a power supply putting a strong positive voltage on it). So a weak sine wave signal on the plate will lead to a big sine wave current from the plate.
There, now you know the basics of amplification (although I skipped some details). I couldn't have done it by describing a BJT (transistor), because they're far weirder.
Parent
Re: (Score:3, Insightful)
You can learn a hell of a lot from vacuum tubes! They are far easier to understand than transistors.
For someone studying electronics, I agree. But as a general subject? Why not teach the theory on how they used to slop pigs 100 years ago? Or the techniques for cutting hair? Or pick your esoteric piece of knowledge that is utterly useless to 99% of students.
The next logical step... (Score:5, Funny)
First Thought... MEVs (Score:4, Interesting)
"Male Enhancer Volume System Product"
How much juice/oomph can YOUR tubes deliver?
14.524MHz? (Score:2)
Re: (Score:3, Interesting)
i have a nice R.L. Drake shortwave receiver and love to listen to HF a lot, so when ham radio is the topic the HF bands are what i automatically think of...
Upping the coolness factor (Score:5, Interesting)
The only thing that would make this cooler is if he made his own Nixie tubes!
I thought there were issues not addressed clearly in the video. First, I thought I learned in college chemistry (now rummaging in decades-old longterm storage media) that one of the big problems was getting a good seal of glass around metal, which wasn't solved until they put together the right glass with the right metal.
Also, aren't the electrodes in a vacuum tube coated with something to prevent early breakdown? And isn't there some chemical you have to put inside the tube to absorb the gas given off when electrons smash into the electrodes? So while this is incredibly neat-looking, I don't think the tubes would last very long...
--Rob
Glass/Metal seals... (Score:5, Informative)
Before the development of dumet, kovar, and other specialized alloys, the seals in very early tubes were made using platinum wire. Cost considerations brought this to a quick end, as soon as cheaper suitable materials were developed.
The electrodes in later tubes were often coated with various materials to aid heat dissipation or reduce secondary electron emission. Early tubes that were similar in construction to what is being made here generally used plain metal grids and plates.
Most tubes contained a "getter" made of barium or other reactive metal, to adsorb any gas molecules which survived initial pumpdown, or which were liberated from the internal elements during operation.
Parent
Re:Getter (Score:5, Interesting)
I am not sure what material he was using for his filament wire, but if it was thoriated tungsten, then the "hot shot" cycle also serves to build up a surface layer of thorium oxide on the filament, and reduce it to metallic thorium. Thorium has a much lower work function than pure tungsten, and will emit electrons efficiently at a much lower operating temperature.
Yes, I am a tube geek...:) Years ago, I made a much cruder triode in a peanut butter jar as a HS physics project.
Parent
you might have noticed the plate red hot in a coil (Score:5, Interesting)
many getters at the period in which that tube type he's duplicating used phosphorus. not as efficient as aluminum and barium, but easier to flash over. WWI, remember, you couldn't pull much vacuum. the getter had to do the job. so old tubes had funny colors inside from the getter flashover.
Parent
State of the Art (Score:5, Informative)
I do have to say this is one of the most impressive projects of its type I've ever seen; it's clearly a labor of both love and skill.
Parent
He not only made the tube, (Score:5, Informative)
I'll Out-Retro You (Score:4, Funny)
Vacuum tubes were pretty much ALL hand-made.... (Score:5, Interesting)
Once the mounts were assembled and welded onto the stems, the sealing into bulb and pumping down was somewhat automated. Done on a machine called a "sealex", the mounts would be inserted into bulbs, sealed in place, evacuated, heated to activate the cathodes, sealed off, and getters flashed, with each operation taking place at a different "station" on the sealex.
An interesting photo essay on the construction of the famous 300B audio triode is available here:
http://www.westernelectric.com/history/tour01.html [westernelectric.com]
So how were the electron guns made? (Score:3, Informative)
But the heart of the CRT, the electron gun, with it's tiny metal components, was still hand assembled, by operators using microscopes and tiny resistance spot welders. Just the same as standard receiving tubes. The final assembly and evacuation lent itself to automation, but the intricate assembl
I'm impressed (Score:5, Funny)
Re: (Score:2)
Re: (Score:3, Informative)
Bicycle tyres are inflated to up to 80 pounds per square inch.
A submarine has to undergo far greater pressures, even though the air is kept at say 1 Atm internally the pressure underwater goes up by 1Atm per 10m depth so the pressure at say 915m depth would be 1316 pounds per square inch! (record manned sub wit
if you ever had a cathode-ray tube implode on you. (Score:3, Informative)
gas-filled tubes typically flash over as the gas starts conducting, typically violet for argon, bright yellow for hydrogen. because of the flashover point at some voltage, gas tubes are generally trigger tubes or voltage regulators.
glass in CRTs typically is thick enough to withstand tons and tons of atmospheric pressure. sometimes, they don't. that is rather spectacular, unless you are touching the glass, in which case is is amputational.