[HN Gopher] The Tube Computer
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The Tube Computer
Author : elvis70
Score : 221 points
Date : 2024-12-03 18:54 UTC (1 days ago)
(HTM) web link (www.thetubecomputer.com)
(TXT) w3m dump (www.thetubecomputer.com)
| mikewarot wrote:
| Fuses help with the "bang", as do using 5U4 or other vacuum tube
| diodes in the power supply, which limit current. I've learned not
| to be absolutely frightened of B+ at 200-300 volts, though I
| definitely respect it. Once you get above 500 volts, and an
| amp... the danger is very real, and the fear returns, in spades.
| monocasa wrote:
| That being said, the biasing voltages get crazy too, leading to
| the big boy voltages.
|
| 300v b+ combined with 200v c- means that you're at 500v of
| potential if you short the wrong bits that are probably right
| next to eachother.
| peatandrepeat wrote:
| Exactly why I keep wooden chopsticks in my amp repair kit.
| But the voltage is moot without the amperage to back it up,
| and most power transformers will happily supply it in heaps.
| ownlife wrote:
| "The basic, domestic quality thermionic tubes have codes for a
| projected life span of either 1500 (6N3P-E) or only 500 hours
| (6N3P). Many were used and then stored for over 50 years, quality
| stamps may have been accidentally altered, so life expectancy may
| be questionable, both for the tubes and for me!"
|
| I love the idea of an expiration date, or at least an ever-
| present need for repair. It emphasizes the idea that the computer
| is a machine, subject to the constraints of the physical world.
| There's something charming about that.
| fortran77 wrote:
| I restore a lot of 50s era tube radio equipment. The tubes are
| suprisingly robust!
|
| I'm surprised at how many times _resistors_ go bad, and of
| course we all know that capacitors fail. But more often than
| not, all the tubes in a typical 5 tube AM radio I find are
| working.
| dhosek wrote:
| Radio Shacks1 used to have a tube tester machine in them.2 I
| was always impressed that there was such a finite universe of
| tubes that a single machine could test all of them.
|
| [?]
|
| 1. For the kids, this was a store that sold various electric
| gizmos including radios and circuit components, then later
| computer and televisions.
|
| 2. I _think_ they may have also been present in hardware
| stores as well.
| euroderf wrote:
| There was a tube tester in our town's main pharmacy.
|
| So in principle you could pull the main tubes from (say)
| your TV and have at it.
| quercusa wrote:
| There's a HeathKit one up on Ebay now: 'Heathkit TC-3 Tube
| Tester'
| retrac wrote:
| Bit of an aside but I wonder how far tube technology might have
| advanced, without semiconductors intervening. In the late 1950s
| and early 1960s, GE, IBM, and RCA, probably other companies, were
| working on "integrated tubes" with many components in a single
| envelope, as well as techniques for easier and more automated
| manufacture. For example, introduced in 1959:
| https://upload.wikimedia.org/wikipedia/commons/b/ba/Nuvistor...
| Animats wrote:
| > Bit of an aside but I wonder how far tube technology might
| have advanced, without semiconductors intervening.
|
| There were Compactrons. There were subminiature vacuum
| tubes.[1]
|
| A one piece printed circuit board of glass, with multiple
| tubes, might be possible. A glass plate made with lots of
| recesses, electrodes and wiring created by photo-etching like
| printed circuit boards, a glass plate on top, pumped down to
| vacuum and sealed. A low-density integrated tube.
|
| That's what a plasma panel display is. It's an integrated array
| of neon lamps. In a vacuum fluorescent display, each
| illuminated element is a triode vacuum tube. So it's quite
| possible to fabricate a big array of tubes.
|
| Maybe something like a ball grid array would work for external
| connections.
|
| Probably could have been done if necessary. Density probably
| would have maxed out around the density of elements on on the
| most dense vacuum fluorescent displays. Maybe devices at 1mm
| scale, or 1,000,000 nm. Good enough for mainframes and
| minicomputers, but not microprocessors.
|
| [1]
| https://archive.org/details/The_MIT_Museum_The_Subminiature_...
| adrianmonk wrote:
| Would tube reliability have limited how much you could scale it
| up? As far as I know, tubes have a limited lifetime and burn
| out eventually. If you have a million or a billion of them,
| they might fail so fast that your computer simply doesn't work.
|
| I don't know whether reliability is a solvable problem. Tube-
| based devices were once very common, so that suggests it would
| have been solved if it could have been.
| klodolph wrote:
| Tubes have a limited lifetime, but high-reliability, long-
| life tubes were developed specifically for digital circuits.
|
| One such development was a change in alloys for the
| filaments. It turns out that the filaments were made from a
| tungsten alloy containing silicon, and the silicon evaporates
| and is deposited on the cathode. The cathode has a special
| coating to help it emit electrons, and the silicon deposits
| would interfere. From what I can tell, the alloy for
| filaments had silicon in to make it easier to draw through
| the dies necessary to construct the filament in the first
| place, so there is some tradeoff between the lifetime of the
| tools used to make the tubes and the lifetime of the tubes
| themselves.
|
| This is not entirely unlike the problems faced by
| semiconductor manufacturers--problems with impurities, solid
| state chemistry, and vapor deposition. I can imagine an
| alternate timeline with extremely long-lived vacuum tube
| circuits.
| shrubble wrote:
| I recently read up on "zone melting" which was developed to
| purify germanium - but of course this same method can be
| used for other materials. Interesting that Hamming of
| Hamming codes fame gave encouragement to the developer of
| this materials process: https://fs.blog/great-
| talks/richard-hamming-your-research/ (search for Bill
| Pfann)
| actionfromafar wrote:
| Say a CPU was made the size and shape of a plasma TV. You
| wouldn't have to run it all at once. You could make many CPUs
| or logic blocks and re-route traffic to hitherto unused
| blocks when a fault was detected.
| anyfoo wrote:
| Oof. I don't know much about tubes, do they always fail in
| ways that are reliable to detect? (E.g. I can imagine that
| detecting a burned out heater is easy, but I don't know
| what other common failure modes there are.) And even then
| there's a lot of effort to just make the system "switch
| over"... and a lot of extra real estate with technology
| that was already constrained by the minimum size bound of
| the tubes.
| actionfromafar wrote:
| I was thinking pretty high level stuff, like running a
| quorum of CPUs or something. But it could also be a
| manual thing with switches on a panel. :)
| marcodiego wrote:
| For a long time I've been thinking about building one based on
| relays. The problem is that I would need a lot of relays just to
| achieve anything very simple. My solution: think about the
| simplest computer architecture I could come up with, and the
| simplest one was a NAND computer. In this architecture, the
| program is a simple loop with instructions all in the same
| format: input addess 1, input address 2, output address. The only
| supported instruction simply writes at the output address the
| result of a NAND operation of the input addresses.
|
| Since any circuit can be built using only NAND's, this computer
| can simulate any circuit, including the circuit of a Turing
| complete CPU. It certainly would be very slow, but relatively
| simple to build. I still have to think about a good type of
| memory for this machine. Maybe one day I'll take the courage to
| build it.
| fragmede wrote:
| http://nandgame.com might help with that
| mrob wrote:
| For something simpler than the computer described in the
| article, you might be interested in Usagi Electric's UE-1
| vacuum tube computer. Construction is nearing completion, and
| it's documented on Youtube:
|
| https://www.youtube.com/playlist?list=PLnw98JPyObn0v-98gRV9P...
|
| This is a 1-bit design based on the Motorola MC14500B:
|
| https://en.wikipedia.org/wiki/Motorola_MC14500B
|
| Code executes directly from a literal loop of paper tape, so
| the clock speed is very slow. I expect this design would also
| work with relay logic.
| anyfoo wrote:
| Yes, code executes directly from a literal loop of paper
| tape, and more specifically, there is only _one_ loop (the
| paper tape loop), and _every_ instructions executes at every
| iteration.
|
| Yet it can do what any other computer can do (in terms of
| computation, not I/O), because not every instruction has to
| actually effectively _do_ something in each iteration, and it
| is a cornerstone of theoretical computer science that you can
| transform every program into one represented in an academic
| language called "WHILE", which is restricted to exactly that
| principle: It only consists of a single outer WHILE loop, and
| then inside the loop you have a bunch of conditions.
| volemo wrote:
| That's how tom7's printable executable [1] works!
|
| [1]: https://youtube.com/watch?v=LA_DrBwkiJA
| anyfoo wrote:
| Yup, having an emulator for another, more complex architecture
| running on the very simple architecture is common amongst
| projects like this. Linux on Intel 4004 does exactly this:
| https://dmitry.gr/?r=05.Projects&proj=35.+Linux4004
|
| And its predecessor project(s) do as well.
|
| Usagi's UE-1 was already mentioned as another vacuum tube
| computer. It indeed just runs instructions in a loop, and runs
| _every_ instruction in each loop (but not every instruction is
| always effective).
| cyberax wrote:
| There's a Brainfuck relay computer:
| https://hackaday.io/project/18599-brainfuckpc-relay-computer
|
| Its author is now building a rack-mounted vacuum-tube based
| computer: https://www.youtube.com/watch?v=2HAf52AKt7Q
| Peteragain wrote:
| https://youtu.be/RfXrT619jBw?si=yWZO9S-PgLs_9DJd He made a
| bigger one a few years later..
| orbital-decay wrote:
| The problem with ultra low gate counts is always memory. No
| matter how simple your CPU is, you still need at least
| thousands of discrete components for it to do anything useful,
| unless you resort to something like Williams tubes or delay
| lines. (Torsion wire delay line is probably the most practical
| form of memory for a computer like this)
| immibis wrote:
| You can build an interesting CPU core out of whatever, and
| then connect it to a silicon SRAM chip, and still say you
| built an interesting CPU core out of whatever.
| Aardwolf wrote:
| Or if you can get your hands on magnetic core memory, that
| might be neat
| immibis wrote:
| I started designing this, designed one using transistors
| instead, and built half of that.
|
| But I think you can built an 8-bit relay version of my 16-bit
| transistor CPU core with on the order of 400 DPDT relays, which
| is on the order of $1000, plus a comparably big bag of diodes,
| which is much less than $1000. This includes registers (10 of
| them), control and sequencing logic (including a diode
| microcode matrix), but not RAM, which you wouldn't want to make
| from relays. (To make an 8-bit version you'd probably have to
| add another 3 upper address registers, to still have 16-bit
| addresses.)
| EMIRELADERO wrote:
| So, if this became sufficiently popular to a degree in which many
| more units like these were produced and released, and it was
| decided that they all should be connected somehow, in a sort of
| inter-network...
|
| ...it would finally be a series of tubes.
| debo_ wrote:
| From the website: The person who built this appears to be (at
| least) 70 years old. Amazing!
|
| > My family was homeless when I was born. But my parents found
| work, the council found us a flat, and 20 years later my dad was
| the managing director of a very large engineering firm, and my
| parents built a fabulous home.
|
| > To cut a long story short, much later my parents had a few
| personal problems, and sadly my mum finally killed herself. I
| don't think you ever get over it, you really just learn to live
| with it.
|
| > My life then went a bit pear shaped. I trusted bad people and
| guess what, really bad things happened. Very kind friends managed
| to put me back on my feet, and then, at 55, I met Judy and her
| family, and we've had the most wonderful 15 years together.
|
| > So please, what ever happens, please don't give up.
| lalabert wrote:
| "So please, what ever happens, please don't give up."
|
| Love that - thank you!
| lalabert wrote:
| Tommy Flowers (https://en.wikipedia.org/wiki/Tommy_Flowers) knew
| a thing or two about valves (and how reliable they were if not
| switched off!). We have him (amongst many others) to thank for
| the success of Bletchley Park.
| ForOldHack wrote:
| Brilliant! and warming. ( literally and figuratively. )
|
| "My family was homeless when I was born. But my parents found
| work, the council found us a flat, and 20 years later my dad was
| the managing director of a very large engineering firm, and my
| parents built a fabulous home.
|
| To cut a long story short, much later my parents had a few
| personal problems, and sadly my mum finally killed herself. I
| don't think you ever get over it, you really just learn to live
| with it.
|
| My life then went a bit pear shaped. I trusted bad people and
| guess what, really bad things happened. Very kind friends managed
| to put me back on my feet, and then, at 55, I met Judy and her
| family, and we've had the most wonderful 15 years together.
|
| So please, what ever happens, please don't give up."
| xupybd wrote:
| I'd really love to know more about him. That seems super
| interesting. Also to see this level of creativity after
| retirement is encouraging.
| equestria wrote:
| In my experience, it's more common than we suspect. I've met
| quite a few people in their 60s with fascinating hobbies.
| Some of it boils down to the fact that they had many decades
| to get good - and with career in the rearview mirror and
| adult children, they have a lot more time, too.
|
| But it's also true that with age, you lose the drive to get
| praise from strangers - so at best, you get a text website
| viewed by hundreds, not a series of TikTok or YouTube videos
| viewed by millions. And sometimes, not even that website.
|
| When that person dies and leaves behind a man-sized vacuum
| tube computer, or a collection of vintage calculators, or
| something of that sort... the heirs usually don't have the
| willpower to carry on, and because the stuff is impossible to
| sell, it's often destined for the dump. Maybe a couple of
| years in a storage unit before that.
|
| It's even worse with digital assets. Who's gonna renew that
| hobby domain or pay that hosting bill? I've seen some really
| valuable online resources disappear after the author died.
| anyfoo wrote:
| > Who's gonna renew that hobby domain or pay that hosting
| bill? I've seen some really valuable online resources
| disappear after the author died.
|
| This is why the Internet Archive is so important.
| equestria wrote:
| Eh, kinda. It technically preserves content, but it has
| almost zero discoverability. The site disappears from
| Google & co, so unless you come across a dead link in
| some old HN or Reddit thread, you won't even know it's
| there.
| anyfoo wrote:
| I didn't say it's _sufficient_ , but without the
| preservation that the Internet Archive does, we'd be
| completely lost.
|
| I have come across some wealth of deeply technical
| information by entering dead links on still live pages in
| the wayback machine, and _then_ following crosslinks from
| there to further old sites. I shudder to think what would
| have been if I hadn 't found the dead links in those
| cases, and I'm sure I still missed a lot because I didn't
| know it was there. So yes, this is a very real problem.
| 8bitsrule wrote:
| Yep. It helps IA that there are people keeping track of
| old URLs and making sure that they get added to the
| store.
|
| One thing they've added to their extension lately is a
| count of how many times a page/site has been saved. If
| one finds a great resource with a no- or low-count, it
| can be added at your request; sometimes it will ask if
| you want to save the page.
| 8bitsrule wrote:
| "so at best, you get a text website viewed by hundreds, not
| a series of ... videos viewed by millions."
|
| As my music-maker friend once put it, "it's not so
| important much how _many_ like it, but _who_ likes it. "
| djmips wrote:
| Or put a couple million into your stinky living computer
| museum!
| Optimal_Persona wrote:
| From down the tubes to a much more solid state of
| existence...bravo!
| akdor1154 wrote:
| > The IBM700 series was the most successful 1950s computer
| system. ... Able to handle 36 bit words using 18 bit
| instructions, it could be rented for $12,000 a month.
|
| That's cheaper than an AWS p4d.24xlarge.
| ChrisMarshallNY wrote:
| Not if you scale those dollars to 2024 Buck$. Back then,
| $12,000 was a _lot_ of money. You could rent a whole office
| building, yearly, for that (actually, you could probably buy
| it, outright).
|
| These days, there are flats in NY and SF that go for more than
| that.
| Yawrehto wrote:
| Apparently 12,000 dollars in 1959 even is over $100,000 today:
| https://measuringworth.com/dollarvaluetoday/?amount=12000&fr...
| klodolph wrote:
| > Vacuum Tubes require high voltages to work efficiently and are
| not for the faint hearted.
|
| People used to build vacuum tube circuits on breadboards at home
| back in the 1950s. They seem pretty frightening by today's
| standards, but they're a lot like big, hot, high-voltage, low-
| current transistors. The low-power tubes used for signals are not
| that hot, just kind of warm.
|
| I'm not really criticizing here, I just want people to think of
| vacuum tubes as accessible to people with any kind of electronics
| background, and just more inconvenient than transistors.
| neuralRiot wrote:
| Most people will get frightened by a medium-high or high
| voltage, but low voltage at high currents needs care too, a
| small short circuit could mean a huge fire. When I was studying
| we had to disassemble a decomissioned tube computer, the tubes
| were the sub-miniature type, the double triodes were just a bit
| bigger than a incandscennt christmas tree light bulb.
| TheOtherHobbes wrote:
| Plate voltages can exceed the skin breakdown voltage of ~450V,
| which potentially makes them more dangerous than a domestic
| mains supply.
| klodolph wrote:
| Start with 150 V instead.
|
| You probably don't need voltages that high. DIYers can stick
| with 200 V or something reasonable. The remaining people who
| deal with 450 V are probably servicing guitar amps.
|
| Plate voltages _can_ exceed much more than 450 V. The 811A is
| rated for 1500 V of plate voltage. But the same is true for
| transistors--you can find transistors with similar voltage
| ratings.
| bezkom wrote:
| How long before an audio manufacturer will implement some kind of
| DSP on this thing and marketing it as having "tube warmth"?
| ginkgotree wrote:
| I build Vacuum tube audio amplifiers, mostly Push-Pull class A's
| with EL84s. This is next level. Absolutely awesome!!
| Optimal_Persona wrote:
| Ooh those must sound glorious! I've never played through one,
| but have been close to Vox AC30 guitar amps cranked up loud!
|
| For non-musician HN'ers, if you've heard Brian May with Queen,
| that's the sound of overdriven Class A EL84s!
| unit149 wrote:
| >using 18 bit instructions, it could be rented for $12,000 a
| month.
|
| Release of the IBM700 utilized 6N3P diodes, that tend to burn out
| due to voltage alterations, until the 7000 series, with System
| 360 was transistorised.
| kazinator wrote:
| It's possible to build a switch so that these 62NP tubes are
| interchangeable with 12AX7 (or ECC83).
|
| Instructions in this thread:
|
| https://www.diyaudio.com/community/threads/6n2p-ev-vs-12ax7....
|
| Pins 9 and 5 of the tube socket must be galvanically disconnected
| from the PCB. The switch is then interposed there.
| hilbert42 wrote:
| Wonderful project. I learned vacuum and solid-state electronics
| in parallel so I'm familiar with tube electronics. My fascination
| with valves go back to my early childhood when I used to move our
| console-type radio from the wall and touch the grid-1 spigot
| connection which would make a loud humming sound much to the
| horror and chagrin of my parents.
|
| One of the problems I've witnessed with training in electronics
| these days is how little time is devoted to vacuum tube
| electronics. Perhaps that's a necessity given constraints of
| course time etc. but without an understanding of how vacuum tubes
| work an important part of one's understanding of the subject is
| missing.
|
| Vacuum tube technology is still a vitally important part of both
| electronics and of physics experimentation. For instance,
| magnetrons (microwave ovens, radar, etc.), klystrons, TWTs
| (travelling wave tubes), high power transmitting tubes (TV, FM)
| all rely on vacuum tech. So too do PMTs (photomultipliers) and
| imaging devices such as vidicons and orthicons. In physics,
| understanding thermionic emission is essential to understanding
| thermodynamics, so too cold cathode emission and related tech
| such as vacuum deposition, etc. Even electron microscopes and
| similar instrumentation relies on vacuum technologies.
|
| Unfortunately, now since the widespread adoption of semiconductor
| electronics much of that vacuum tech tends to be rather
| specialized so those who've an interest in learning the subject
| don't get any hands-on experience at an early age.
|
| What's great about this project is that it brings vacuum
| technology to the fore where it can be not only seen but also
| demonstrated.
|
| Learning the transfer characteristics of thermionic diodes and
| triodes is an excellent way to gain such experience. And to begin
| one doesn't have to go to such lengths as this amazing project,
| starting with a single tube superregenerative FM receiver is a
| good place to start.
| taikahessu wrote:
| And future proof! Made me question my sanity for a moment.
|
| "(c) 2025 TheTubeComputer.com"
| Aardwolf wrote:
| > They can switch several hundred million times a second, and in
| the 1950s they were combined with germanium diodes as the basis
| for many incredible computer designs.
|
| Whoa, I didn't know they could switch that fast! Because afaik
| vacuum tube computers were measured in thousands of mathematical
| operations per second
| volemo wrote:
| I guess it's highly dependent on the type of the tube. The
| documentation [1] for the 6N3P (the one Mike uses) talks about
| input resistance at 100 MHz, so the tube must handle at least
| as much.
|
| [1]: https://www.istok2.com/data/575/
| immibis wrote:
| Keep in mind that's in relation to amplifying analogue
| frequencies around 100MHz. It doesn't necessarily mean you
| can make digital logic that runs at 100MHz
| hoseja wrote:
| >They can switch several hundred million times a second
|
| Huh. Wasn't expecting that.
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