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Hand-Made Vacuum Tubes
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.'"
Neither Make nor Slashdot have the basic decency to name the man: Claude Paillard.
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/
Thanks Claude! That rocks.
the article is over 5+ pages with a lot of details on making something (http://www.make-digital.com/make/vol04/?pg=124&pm=2&u1=friend) - while the author didn't post the data sheets he used an analogy and explained it to do the project, that's what most folks want, at least for this type of article - for more details we usually the companion pages on MAKE, the forums and additional articles we refer to. part of a project like this is a little reverse engineering from an amateur who is ok with exploring things too - regardless, sorry we didn't live up to your expectations.
he also made all the necessary equipment, like vacuum pump. If you are interested in tubes, he says the "musée des arts et métiers" is a reference. This is an engeneering museum in Paris, which has an incredible collection. When I go there, I stay for hours. Do not mistake it with the science, the nature science, or the technology museum (which are also quite interesting).
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.net/~lenyr/ntype-nr.htm
Engineering is the art of compromise.
If you look closely at the wires he is sealing into the glass "press", you will see a short reddish-brown section. This is most likely "dumet", or copper coated nickel/iron. This material is specially designed to have the same coefficient of thermal expansion as glass, and was used as the sealing material in most receiving tubes. The copper coating forms an oxide layer that dissolves into the glass, creating a vacuum-tight seal.
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.
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The silvering has nothing to do with radiation. It is a thin coating of reactive metal to take up any oxygen left in the tube after it has been sealed. If you ever find an old tube where the silver patch has gone white, it is gassy and will not work properly. (It may work to some degree but is also likely to have a strange glow from ionising the gas. Depends how much gas has leaked in.)
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.
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.
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.
Brackets contain world's first nanosig, highly magnified:[.]
vacuum tubes.
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.
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Especially when it's one of these played through one of these.
The 'silvering' in most tubes isn't a screen but is caused by a process called 'gettering' where a small amount of a magnesium or calcium-based compound is burnt off (evaporated) by an external induction coil as part of the final manufacturing process. As the valve is 'gettered', the magnesium/calcium 'cleans out' any small traces of gas left in the envelope.
AT&ROFLMAO
"While vacumn tubes are strictly in the realm of hobbyists and zealous audiophiles"...
Right...like all professional musicians who use an electric guitar are "zealous audiophiles".
remember, vacuum tubes are used in modern appliances, like your microwave ( yes, your magnetron is technically a vacuum tube ), CRT anything ( TV, monitor etc ), high power radio transmitters, guitar amps ( the good ones ).....Claude makes much more than just triodes, see the end section of his video.
The pressure is not really that great 1Atm is about 14 pounds per square inch, with a cylinder and hemispherical shape you can withstand incredible pressures, you just cannot have any weak spots.
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 with full crew 1968)
you wouldn't have asked. that glow is vacuum. good old vacuum.
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.
if this is supposed to be a new economy, how come they still want my old fashioned money?
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.
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 tubes can easly be modeled in a DSP.
http://emusician.com/dsp/studio_devil_virtual_guitar_amp/
http://www.analog.com/processors/tigersharc/overview/customerstories/fractalAudio/fractalAudioIndex.html
http://www.sweetwater.com/store/detail/FM15DSP/
The truth shall set you free!
The article talks at great length about the manufacture of the CRT bulbs, and the exhaust process, both of which were easily automated, even back then. I talked about the automated "sealex" machines in my last post.
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 assembly of the "guts" did not.
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