"You're always building models. Stone circles. Cathedrals. Pipe-organs."
October 29, 2020 10:36 AM Subscribe
The 11 greatest vacuum tubes you've never heard of.
Carter M. Armstrong in IEEE Spectrum lays down the law on the vacuum tubes that receive too little honour.
The Telefunken VF14M, as used in the Neumann U47 and U48 microphones, is of course in there.
Carter M. Armstrong in IEEE Spectrum lays down the law on the vacuum tubes that receive too little honour.
The Telefunken VF14M, as used in the Neumann U47 and U48 microphones, is of course in there.
Also somewhat related are Blueglow's Youtube channel (and relax to his soothing old school Winston-Salem area accent) and Mr Carlsons Lab Youtube channel (and relax to his soothing Canadian accent).
posted by NoMich at 11:04 AM on October 29, 2020
posted by NoMich at 11:04 AM on October 29, 2020
And I’ve pretty much stuck with radio-frequency tubes, so I’m ignoring the vast panoply of audio-frequency tubes
I felt a great disturbance in the net, as if millions of guitarists suddenly cried out in annoyance and closed their browser windows.
posted by doubtfulpalace at 11:07 AM on October 29, 2020 [7 favorites]
I felt a great disturbance in the net, as if millions of guitarists suddenly cried out in annoyance and closed their browser windows.
posted by doubtfulpalace at 11:07 AM on October 29, 2020 [7 favorites]
[Gyrotrons] have also been explored for nonlethal crowd control, in the U.S. military’s Active Denial System. This system projects a relatively wide millimeter-wave beam, perhaps a meter and a half in diameter. The beam is designed to heat the surface of a person’s skin, creating a burning sensation but without penetrating into or damaging the tissue below.some problematic tubes here tbh
[...]
Due to their small size, low weight, and high efficiency, MPM amplifiers found immediate use in radar and communications transmitters aboard military drones, such as the Predator and Global Hawk, as well as in electronic countermeasures.
posted by theodolite at 11:13 AM on October 29, 2020 [6 favorites]
Almost all of those have "Mad Scientist Takes Over The World" vibes
posted by AzraelBrown at 11:28 AM on October 29, 2020 [3 favorites]
posted by AzraelBrown at 11:28 AM on October 29, 2020 [3 favorites]
Yeah this is the crazy mad scientist end of electrical engineering, high powered microwave antennas and phased-array radars and electron beams glowing in an enclosed vacuum that will never release a photon that a human eye will absorb. I feel like joking that I saw the Klystrons play in a dive bar in Cambridge MA back in '92 but honestly this article is just too pure and good for the regular Metafilter hijinks.
He figured that this undulation could result in a periodic interaction with an electromagnetic wave in a waveguide. That, in turn, could be useful for creating exceedingly high levels of peak radio-frequency power. Thus, the ubitron was born.
This is the discipline that makes Turbo Encabulator scripts seems positively straightforward. These people always had huge labs in my university EE department that were always busy but somehow no one was ever seen going in or out? They looked like Frakenstein's laboratory with honest to god 4 meter tall van der graaf generators and various high-power transmission line lab setups. Most EE labs were just wiring a few transistors and some ICs together along with a few biasing resistors, but the microwave labs had machined square brass tubes that weighed a lot and had to be bolted together and you got told to point them in a certain direction so you didn't accidentally cook your own spleen.
Computer programming is fun and pays well but this part of electrical engineering is straight up forbidden Hyborean lore where there's a perfectly good theory to explain everything but once the cathode heats up and the electrons start getting accelerated it's all bind faith and the hope that the calculus really works out. If a resurrected British radar engineer from the 30's showed up one day and said there were no electron beams, just bottled malevolent spirits I think most people would be easily convinced.
I mean, how can you hold up a medical magnetron and explain that this thing somehow fixes brain tumours? I know precisely how it works yet at the same time it really, really makes no sense.
posted by GuyZero at 12:23 PM on October 29, 2020 [10 favorites]
He figured that this undulation could result in a periodic interaction with an electromagnetic wave in a waveguide. That, in turn, could be useful for creating exceedingly high levels of peak radio-frequency power. Thus, the ubitron was born.
This is the discipline that makes Turbo Encabulator scripts seems positively straightforward. These people always had huge labs in my university EE department that were always busy but somehow no one was ever seen going in or out? They looked like Frakenstein's laboratory with honest to god 4 meter tall van der graaf generators and various high-power transmission line lab setups. Most EE labs were just wiring a few transistors and some ICs together along with a few biasing resistors, but the microwave labs had machined square brass tubes that weighed a lot and had to be bolted together and you got told to point them in a certain direction so you didn't accidentally cook your own spleen.
Computer programming is fun and pays well but this part of electrical engineering is straight up forbidden Hyborean lore where there's a perfectly good theory to explain everything but once the cathode heats up and the electrons start getting accelerated it's all bind faith and the hope that the calculus really works out. If a resurrected British radar engineer from the 30's showed up one day and said there were no electron beams, just bottled malevolent spirits I think most people would be easily convinced.
I mean, how can you hold up a medical magnetron and explain that this thing somehow fixes brain tumours? I know precisely how it works yet at the same time it really, really makes no sense.
posted by GuyZero at 12:23 PM on October 29, 2020 [10 favorites]
A New Old Stock (NOS) - e.g. never used - VF14M is such an integral part of the classic U47 mic sound that they'll run you about $4K if you can find them. There's a cottage industry of converting the mics to use a different but similar tube.
posted by Candleman at 12:30 PM on October 29, 2020 [1 favorite]
posted by Candleman at 12:30 PM on October 29, 2020 [1 favorite]
If you want a lot more detail on the VF14M and the U47.
posted by Candleman at 12:43 PM on October 29, 2020 [2 favorites]
posted by Candleman at 12:43 PM on October 29, 2020 [2 favorites]
Voodoo. Pure Voodoo.
Thank you for inviting me to this entirely strange, unfamiliar but fascinating dance spectacle. It was dance, wasn't it? Whatever, it was very very interesting.
posted by From Bklyn at 12:56 PM on October 29, 2020
Thank you for inviting me to this entirely strange, unfamiliar but fascinating dance spectacle. It was dance, wasn't it? Whatever, it was very very interesting.
posted by From Bklyn at 12:56 PM on October 29, 2020
The French tube called the carcinotron is another fascinating example born of the Cold War. Related to the magnetron, it was conceived by Bernard Epsztein in 1951 at Compagnie Générale de Télégraphie Sans Fil (CSF, now part of Thales).
The name "carcinotron" makes me think it's used to cause rather than treat cancer...
And the strange name? Philippe Thouvenin, a vacuum electronics scientist at Thales Electron Devices, told me that it comes from a Greek word, karkunos, which means crayfish. And crayfish, of course, swim backwards.
Ah. Never mind.
posted by mandolin conspiracy at 1:13 PM on October 29, 2020 [1 favorite]
The name "carcinotron" makes me think it's used to cause rather than treat cancer...
And the strange name? Philippe Thouvenin, a vacuum electronics scientist at Thales Electron Devices, told me that it comes from a Greek word, karkunos, which means crayfish. And crayfish, of course, swim backwards.
Ah. Never mind.
posted by mandolin conspiracy at 1:13 PM on October 29, 2020 [1 favorite]
For sheer gobsmacking WTFery, I give you the 8974: only 1.5 MW maximum plate power from 600 A blatting through its thoriated tungsten filament. Although only 60 cm long, it weighs about as much as a full Marshall stack.
Your guitar amp valves are weak.
posted by scruss at 3:31 PM on October 29, 2020 [1 favorite]
Your guitar amp valves are weak.
posted by scruss at 3:31 PM on October 29, 2020 [1 favorite]
"two section thoriated tungsten filament"
easy, this is a family-friendly site. you can't use language like that here!
also, a 22kV 125A cable is no joke. I guess it's obvious once you think about it that TV and radio transmitter towers have a single path for signal amplification (which radiate ~ 80 kW), but it's a little shocking to think that much power is flowing through a single tube.
posted by GuyZero at 4:16 PM on October 29, 2020
easy, this is a family-friendly site. you can't use language like that here!
also, a 22kV 125A cable is no joke. I guess it's obvious once you think about it that TV and radio transmitter towers have a single path for signal amplification (which radiate ~ 80 kW), but it's a little shocking to think that much power is flowing through a single tube.
posted by GuyZero at 4:16 PM on October 29, 2020
Also, exciting news, the electrode of a thoriated tungsten-based tube is also radioactive!
posted by GuyZero at 4:17 PM on October 29, 2020
posted by GuyZero at 4:17 PM on October 29, 2020
One feature of that article that stands out to me is how many of the inventions happened accidentally, instead of through careful extrapolation of existing theory. Someone noticed that a mistake in design or manufacturing created an unintended effect and investigated it, only to discover a new device principle that could be exploited.
It reminds me of how activity-sensing rate-adaptive pacemakers were invented. A pacemaker designer was trying to invent a small system that could measure breathing in an implantable device and was testing ideas in dogs. It used a piezoelectric crystal bonded to the inside of a sealed implanted pacemaker can to generate a signal as the dog's breathing deflected the surface of the can. The breath signal was being obscured by the motion of the dog, so they kept trying to tie the dog down more tightly in hopes that they could see the respiration signal.
It finally dawned on the designer that the "noise" was measuring the dogs activity, and that that signal could be used to adapt the rate of a pacemaker to increase with more activity and decrease with less. The concept led to Medtronic's Activitrax, the first rate-adaptive implantable pacemaker.
posted by Mental Wimp at 5:05 PM on October 29, 2020 [4 favorites]
It reminds me of how activity-sensing rate-adaptive pacemakers were invented. A pacemaker designer was trying to invent a small system that could measure breathing in an implantable device and was testing ideas in dogs. It used a piezoelectric crystal bonded to the inside of a sealed implanted pacemaker can to generate a signal as the dog's breathing deflected the surface of the can. The breath signal was being obscured by the motion of the dog, so they kept trying to tie the dog down more tightly in hopes that they could see the respiration signal.
It finally dawned on the designer that the "noise" was measuring the dogs activity, and that that signal could be used to adapt the rate of a pacemaker to increase with more activity and decrease with less. The concept led to Medtronic's Activitrax, the first rate-adaptive implantable pacemaker.
posted by Mental Wimp at 5:05 PM on October 29, 2020 [4 favorites]
Microwaves are weird. Long time back, I had an electronic technician job. One of my duties was tuning a micro wave device. It was a cast metal box, about 10 x 12 inches and four inches high. In it were six chambers. On top, one per chamber were these big screws, an inch in diameter and maybe three plus inches long. I hooked by a microwave signal generator to one corner of the box and a frequency analyzer to another. There were channels between the chambers. I would heuristically adjust the screws until the right frequency spiked on the meter. Then I locked down the screws with a big hexagonal nut. No wires, no components, just a metal box with big screws. I got to be real good at it. I had to teach the engineers who designed them how to tune them. These tubes would fit right in.
posted by njohnson23 at 8:58 PM on October 29, 2020 [5 favorites]
posted by njohnson23 at 8:58 PM on October 29, 2020 [5 favorites]
About a decade ago when I was still living at the crazy artist/music/etc co-op in SF, I was hanging out with ryanrs there.
One of the things they had there was an electronics lab, and a couple people who used it were mad scientist level hackers that liked to mess around with RF amplifiers, including microwave stuff. A couple of them were even gainfully employed at various points as engineers by companies like Google and some telecom companies.
One of the projects laying around was a weird hybrid thyratron-based audio amplifier built into the cooking cavity of a commodity home appliance microwave that used the microwave energy as a power source for the amplification circuit. Imagine a large thyratron tube somehow bodged inside a functioning microwave and to use it as an audio amplifier you had to feed a signal into some threaded bolt taps protruding through the case and a small hole cut into the wire mesh door/window and then turn on the microwave.
It looked like something straight out of /r/VXJunkies which is a subreddit where people roleplay turbo encabulator fake tech, and since I knew ryanrs was an electrical engineer I figured he'd like to see it because he'd probably know what it was.
Well, he sure did immediately recognize what it was and it was the only time I've ever seen him visibly upset, concerned or outright scared by basically anything and I remember his reaction was to immediately stand up, back quickly away and said something like "DON'T YOU DARE TURN THAT FUCKING THING ON ANYWHERE NEAR ME. I'M SERIOUS. GO PUT THAT DOWN RIGHT NOW. WHAT THE FUCK."
I had no intention of turning it on or plugging it in because it looked - and was - dodgy as fuck, but his reaction to it as an experienced EE always stuck with me because it was so much NOPE NOPE NOPE.
posted by loquacious at 7:59 AM on October 30, 2020 [9 favorites]
One of the things they had there was an electronics lab, and a couple people who used it were mad scientist level hackers that liked to mess around with RF amplifiers, including microwave stuff. A couple of them were even gainfully employed at various points as engineers by companies like Google and some telecom companies.
One of the projects laying around was a weird hybrid thyratron-based audio amplifier built into the cooking cavity of a commodity home appliance microwave that used the microwave energy as a power source for the amplification circuit. Imagine a large thyratron tube somehow bodged inside a functioning microwave and to use it as an audio amplifier you had to feed a signal into some threaded bolt taps protruding through the case and a small hole cut into the wire mesh door/window and then turn on the microwave.
It looked like something straight out of /r/VXJunkies which is a subreddit where people roleplay turbo encabulator fake tech, and since I knew ryanrs was an electrical engineer I figured he'd like to see it because he'd probably know what it was.
Well, he sure did immediately recognize what it was and it was the only time I've ever seen him visibly upset, concerned or outright scared by basically anything and I remember his reaction was to immediately stand up, back quickly away and said something like "DON'T YOU DARE TURN THAT FUCKING THING ON ANYWHERE NEAR ME. I'M SERIOUS. GO PUT THAT DOWN RIGHT NOW. WHAT THE FUCK."
I had no intention of turning it on or plugging it in because it looked - and was - dodgy as fuck, but his reaction to it as an experienced EE always stuck with me because it was so much NOPE NOPE NOPE.
posted by loquacious at 7:59 AM on October 30, 2020 [9 favorites]
→
I'd heard (perhaps apocryphally) that that's how the thermionic effect was discovered: early light bulbs were troubled by carbon deposition from the filament on the glass. Some bright spark put a metal plate inside the glass envelope, and was surprised that charge was building up on it.
posted by scruss at 8:05 AM on October 30, 2020
Someone noticed that a mistake in design or manufacturing created an unintended effect and investigated it, only to discover a new device principle that could be exploited
I'd heard (perhaps apocryphally) that that's how the thermionic effect was discovered: early light bulbs were troubled by carbon deposition from the filament on the glass. Some bright spark put a metal plate inside the glass envelope, and was surprised that charge was building up on it.
posted by scruss at 8:05 AM on October 30, 2020
The most exciting phrase in Science isn't "Eureka!" it's "Hmm, that's funny".
posted by Mitheral at 9:34 PM on November 1, 2020 [1 favorite]
posted by Mitheral at 9:34 PM on November 1, 2020 [1 favorite]
« Older "It didn't die. They killed it." | Cape Town's garden of good and evil Newer »
This thread has been archived and is closed to new comments
posted by swift at 10:57 AM on October 29, 2020