Just stumbled on this:
A new vacuum tube which puts vacuum fluorescent display technology to practical use
Nutube, similar to a conventional vacuum tube, has an anode grid filament structure, and operates exactly as a triode vacuum tube. Also similar to a vacuum tube, it creates the same characteristic rich overtones. By applying their vacuum fluorescent display technology, Noritake Itron Corp., a Noritake Co. Ltd affiliated company, have devised a structure which achieves substantial power saving, miniaturization, and quality improvements when compared with a conventional vacuum tube.
Realising substantial power savings
By making the form smaller we have succeeded in making significant power savings requiring less than 2% of the electrical power of a conventional tube. This allows for efficient and simple battery operation.
Nutube is less than 30% of the size of a conventional vacuum tube.
Real vacuum tube sound
The real triode structure produces a warm, unique vacuum tube sound, delivering excellent linearity.
High reliability, long life
Made in Japan. 30,000 hours of continuous life expectancy
KORGSince its establishment in 1963, KORG INC. has always strived to manufacture epoch-making electronic musical instruments using innovative creativity and the company’s own extensive technological expertise. In 1975, KORG introduced the world’s first compact tuner with a needle meter and has marketed innovative products worldwide at the forefront of the musical instruments market. KORG synthesizers combine excellent sound quality and features and have earned the support of music fans and professional musicians everywhere. Today, KORG designs and develops a wide range of electronic musical instruments from synthesizers and tuners, to digital pianos, signal processors, digital recorders and other peripheral equipment.
And for no good reason I want one!!!
The first radios I made were made with vacuum tubes. I find the notion of a Raspberry Pi sized card with a vacuum tube radio on it curiously attractive ;-) Unknown is the ultimate frequency response of these tubes. They are intended for the audio market so might not have the needed MHz range.
The FAQ says it runs on 5 VDC to 80 VDC. Gallery of pictures showing products using it:
All this has me thinking that you could package many of these in one vacuum package (with ion blocking metalized dividers) and a common heater and make a “Vacuum Tube Integrated Circuit”…. God I want to make one! Just to make some head scratch inducing devices out of it ;-)
Now it’s got me wondering just how much you could miniaturize and still have decent performance out of a vacuum tube…
Looks like I’m not the only one wondering:
Could modern, nanoscale vacuum tubes replace transistors?
By Joel Hruska on June 7, 2016
The systems that Dr. Scherer and his research team are working on are nothing like classic vacuum tubes — according to the team, the structures are roughly 1,000x smaller than a human blood cell, which would make them 6-8nm. One problem with modern CPUs is that they suffer from significant amounts of electricity leakage — Scherer’s designs would use leakage current to flip states on purpose, thereby improving efficiency and overall performance.
One reason for this research is that Scherer thinks the microprocessor teams scaling below 10nm will encounter problems. The properties of silicon apparently change at that point, becoming both elastic and emitting light. “It’s a different material, and it gives you this different behavior,” Scherer told the New York Times.
Can tubes replace transistors?
Dr. Scherer isn’t trying to reinvent the transistor or replace the silicon economy. Boeing is funding his research due to its potential applications in space and aviation technologies, and silicon will obviously be the gold standard for everyone for years to come. It’s still interesting to consider the question: Could such a fundamentally different technology, shrunk to a microscopic scale, solve the problems of transistor scaling and performance?
The I-tripple-E IEEE has another POV:
23 Jun 2014 | 16:14 GMT
Introducing the Vacuum Transistor: A Device Made of Nothing
This curious mash-up of vacuum tube and MOSFET could one day replace traditional silicon
By Jin-Woo Han and Meyya Meyyappan
At the NASA Ames Research Center, we’ve been working for the past few years to develop vacuum-channel transistors. Our research is still at an early stage, but the prototypes we’ve constructed show that this novel device holds extraordinary promise. Vacuum-channel transistors could work 10 times as fast as ordinary silicon transistors and may eventually be able to operate at terahertz frequencies, which have long been beyond the reach of any solid-state device. And they are considerably more tolerant of heat and radiation. To understand why, it helps to know a bit about the construction and functioning of good old-fashioned vacuum tubes.
Notwithstanding these advantages, when considered purely as a medium for transporting charge, vacuum wins over semiconductors. Electrons propagate freely through the nothingness of a vacuum, whereas they suffer from collisions with the atoms in a solid (a process called crystal-lattice scattering). What’s more, a vacuum isn’t prone to the kind of radiation damage that plagues semiconductors, and it produces less noise and distortion than solid-state materials.
It is that “less noise and distortion” that has kept the Vacuum Tube alive in specialty audio gear. Turn a semiconductor amp up to full with no input, you hear a whoosing sound. “Cascade noise” as a few electrons “cascade” into noise. Do the same thing with a high end vacuum tube amp, you hear almost nothing. ( I’ve done it, though admittedly it was back in the late ’70s)
But after four decades of shrinking transistor dimensions, the oxide layer that insulates the gate electrode of a typical MOSFET is now only a few nanometers thick, and just a few tens of nanometers separate its source and drain. Conventional transistors really can’t get much smaller.
Then this very interesting bit of practical physics:
But vacuum-channel transistors don’t need a filament or hot cathode. If the device is made small enough, the electric field across it is sufficient to draw electrons from the source by a process known as field emission. Eliminating the power-sapping heating element reduces the area each device takes up on a chip and makes this new kind of transistor energy efficient.
Another weak point of tubes is that they must maintain a high vacuum, typically a thousandth or so of atmospheric pressure, to avoid collisions between electrons and gas molecules. Under such low pressure, the electric field causes positive ions generated from the residual gas in a tube to accelerate and bombard the cathode, creating sharp, nanometer-scale protrusions, which degrade and, ultimately, destroy it.
These long-standing problems of vacuum electronics aren’t insurmountable. What if the distance between cathode and anode were less than the average distance an electron travels before hitting a gas molecule, a distance known as the mean free path? Then you wouldn’t have to worry about collisions between electrons and gas molecules. For example, the mean free path of electrons in air under normal atmospheric pressure is about 200 nanometers, which on the scale of today’s transistors is pretty large. Use helium instead of air and the mean free path goes up to about 1 micrometer. That means an electron traveling across, say, a 100-nm gap bathed in helium would have only about a 10 percent probability of colliding with the gas. Make the gap smaller still and the chance of collision diminishes further.
But even with a low probability of hitting, many electrons are still going to collide with gas molecules. If the impact knocks a bound electron from the gas molecule, it will become a positively charged ion, which means that the electric field will send it flying toward the cathode. Under the bombardment of all those positive ions, cathodes degrade. So you really want to avoid this as much as possible.
Fortunately, if you keep the voltage low, the electrons will never acquire enough energy to ionize helium. So if the dimensions of the vacuum transistor are substantially smaller than the mean free path of electrons (which is not hard to arrange), and the working voltage is low enough (not difficult either), the device can operate just fine at atmospheric pressure. That is, you don’t, in fact, need to maintain any sort of vacuum at all for what is nominally a miniaturized piece of “vacuum” electronics!
Oh my… I think I feel a whole new “everything old is new again” moment happening ;-)
Also has wonderful possibilities for EMP and ESD resistant circuits if it has the true characteristics of a vacuum tube. (given the low operating voltage perhaps not but 5 – 80 v input implies it will survive one order of magnitude voltage spikes on the 5 vdc supply.
Best Class A amps I ever owned we tube based. Back to the future ;-)
Mesa Boogie 22 cal studio- still cranking after all these years. Russia still makes tubes…
Looks cool. I want one too. Vacuum nanoelectronics is not new however. The IVNC just held their 31st annual conference. http://www.vacuumnanoelectronics.org
I’m familiar with this stuff because I’ve been lucky enough to work in nanotech (among other related fields), although not in vacuum nanoelectronics Also, an old friend is past president of IVNC.
Effectively, the vacuum is much the same as a superconductor. Just miniaturise them enough, and vacuum tubes become compatible with standard logic. The frequency response will really depend on the grid size and the flight length, so if the ceramic package shown is around 14mm across and the grid is around 7-8mm, it’ll deal with frequencies up to the several GHz region OK if transmission-line techniques are used for the wires in and out and capacitances are kept small.
For THz-region diodes, we’re already using geometrical designs where electrons are emitted from a cold point and collected on a flat bar, with around a 2nm gap to jump across. Of course, the main problem is actually making things this small and precise.
Vacuum tubes aren’t dead yet.
It isn’t that the vacuum sucks… it’s that the atmosphere blows… ;-)
Hmmm. This makes my retired military mind wonder if this technology would be, like old style vacuum tubes, more resistant to EMP? If so, it would definitely have military applications, as well as add invaluable “hardening” to various space applications, energy distribution grids, communications systems/networks, etc., etc. during solar flares and coronal mass ejections, etc.
I dunno, E.M.
Dyson, Kirby, Hoover, Electrolux, Shark, Shop-Vac; they pretty much all suck. Well, unless you hook up the hose attachments to the wrong end. Then your assessment is spot on.
Heard once in a lab…
“Oh No! My vacuum is leaking out!! “….
I really hope your wife was not around when you wrote this. You sound as excited as when you first married her! :-)
Tubes have always fascinated me. But in the solid state age, I have long grown immune to their lure (heat being a major factor). My wife has a tube radio – antique. And no, it does not work any longer. But had I the time, I would not mind playing with the new smaller ones.
“The first radios I made were made with vacuum tubes.”
That’s cheating, my first radio used a germanium diode and a toilet roll centre.
OK, ok, my first REAL radio was vacuum tubes…
I did make a couple of crystal things that didn’t work worth a damn. Yeah, it could pick up something like 2 stations that you could almost hear … but it was more a proof of concept demonstrator than an actual radio, IMHO.
I made them just long enough to go “Hey, it makes noise. Not worth listening to anything though.”
The regenerative detector single tube radio was my first REAL radio. Then an added audio section made it nice with a speaker. Still have a fondness for regenerative detectors…
Most of the time those old sets stop working for one of two reasons.
1) Tube has burned out. Look at them. Any not glowing likely need replacing. More subtle degradation of properties (transconductance, microphonic loosening of parts) usually don’t prevent operation. A little gassy doesn’t hurt too much either, and lots of gas either cases a blue glow or the tube stops glowing at all…
2) If old, the most common problem is the wax / foil / paper capacitors are shot. Usually shows up as hummm first as the filter caps on the filaments stop filtering. Easy to replace the capacitors. The ceramic disk ones are pretty much bullet proof so not worth worry unless physically broken. Same thing with resistors.
I’d expect about 5 bench hours to fix it, not counting time buying tubes or caps…
But Lucille Ball had a radio in her mouth with saliva connecting 2 silver fillings! ;-)
This is one of my favorite videos:
Also, check out some of the DX crystal sets. Pretty impressive:
Oops – video won’t play from here. Search on “claude paillard vacuum tube video”
Reply:[ Or just click the video again and it takes you to YouTube directly… -EMS]
@jim2: That’s a great link in your 10:20 pm comment. I bookmarked that one.
Impressive link on the DXing. Though I note he started out as I did:
“If you are anything like most radio ‘nuts’, you probably had a crystal set when you were a kid. Thinking back to those good old days, I recall that I could only hear two local stations on my crystal radio.”
Like diy vacuum tube, and it would be great fun to build some, but despite the desire to do it, the time is probably a killer for me… But folks often forget that the first ones were all hand made… They didn’t need a factory and neither do you!
FWIW, somewhere in my “deep doo” kit I have a 2 tube SW radio kit I bought decades ago. Just waiting for “someday” if ever I needed to make a robust EMP resistant radio from scratch to find out what ended the “world as I knew it”… From Australia it uses big UK model tubes ;-)
@Mobile Aviator here:
Sorry I was slow on the approval… busy with being lazy and watching YouTube ;-)
Yes, they are more EMP proof. Not quite as much as big tubes (gaps smaller for discharge arcs, smaller elements fry with lower currents) but more so than semiconductors (less resistive heating, no dopants to migrate, more heat resistant in general).
Perhaps more important, they are also so small you can stuff a bunch of them into a small iron and lead lined box and not add much weight at all. EMP resistant stuff in an EMP resistant / radiation shielding box: Very hard to fry… Add a couple of protective discharge paths (think miniature lightning arrestors) and “Bob’s Yer Uncle!” it ought to be good to go. (Neon Bulbs might make great protective devices. Passive until discharge voltage, then conduct heavily, and react at voltages suited to vacuum tubes while being small enough to not add too much stray capacitance to things… )
So yeah, it adds a very nice new/old option to small avionics…
You can also find surface-mount Gas Discharge Tubes for overvoltage protection. Break-over at 30V is the minimum I’ve seen. They are faster and better than the semiconductor overvoltage devices, but also cost a bit more. Zinc Oxide devices tend to need replacing if they’ve had a large hit, but GDTs degrade much more slowly and, if the current isn’t excessive, have lifetimes in the millions of hits. Protection up to the kA range if you use the 1/4″ devices, and several hundred amps for the SMD devices.
“I made them just long enough to go “Hey, it makes noise. Not worth listening to anything though.” ”
Your preparation for modern TV
Tee Hee ;-)
Yeah, I guess so!
Interestingly enough, I never did like vacuum tube sound. I also do *not* remember them being EMP resistant; though I’m sure that you can make them be (as well as make semiconductors such, too).
I also do *not* remember them being EMP resistant
For most designs the Federal Govt tests when they are actively investigating EMP back in the 1960’s showed that they were approximately an order of magnitude or two more tolerant of voltage spikes than transistors of the day. Modern FET and low voltage IC circuits are much more susceptible to voltage spikes than those 1960’s – 1970’s era discrete transistors but we also do a better job of designing in clamping and surge protection into circuits for ESD protection and stray RF interference (RFI).
The real problem is that EMP surge protection is a system level problem and no matter the tolerance of over voltage for specific components and IC’s the overall system vulnerability depends on the whole system design and how it is used (is it on a dirty unfiltered AC supply or a closely regulated power supply backed up with a purpose designed surge protection system and have maintenance people kept protection intact by not leaving off panels or using out of spec fuses and protective devices – or just been stupid and have power lines draped over other power conductors which might induce large currents in the “protected” circuit behind the surge protection.
Bottom line, without unit specific testing as installed we can only guess.
I built a 5U4 based power supply in about 1970 based on a power transformer from an old TV set. Some times I’d short out the power supply (first time was an accident, but then… ;-)
The plate would warm up and then turn a nice cherry red ;-)
I’d say it was fairly resistant to overheating 8-0 and surge…
I think the capacitors in any device would puncture before the tubes would be an issue…
Various thoughts (apart from many happy memories of hours of playing with valve gear as I learned my skills … I still have some 807’s in the attic, and a 5U4G!):
If you’re not hung up on the miniaturisation, a French radio amateur has made his own firebottles, and gone on the air with them. See here. A real labour of love, and 10/10 to him.
Not quite a crystal set, but for a competition about ten years ago a fellow identified as “Macrohenry” built a single transistor receiver which could drive a speaker to reasonable volume. The trick was to use a reflex regenerative circuit, with a transistor having a gain of about 700x (not that hard these days). Send the signal through it first at RF and then after detection at AF and you’ve got an aggregate gain of about half a million. More here.
And something which has been irritating me (as an old audiophile) for years. Yes, if you play a plasma and a solid state amp beyone their rated power levels, the valves will sound “warmer” because they don’t clip so sharply at the rails. But if you’re overdriving your amps like that, you are driving them into distortion – and the whole point of hi fi is to get rid of distortion, not to try and generate “sweeter sounding” distortion, aaargh. (Mutter, grumble, bitch, gripe …)
Many, many years ago I thought that playing about with vacuum tubes, except of course you would not need tubes, would be a good hobby for bored astronauts (or cosmonauts) on long duration missions.