| ▲ | The Surprisingly Long Life of the Vacuum Tube(construction-physics.com) |
| 50 points by surprisetalk a day ago | 32 comments |
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| ▲ | chromacity 5 hours ago | parent | next [-] |
| I think this is an odd article. It mixes together a variety of technologies that have little in common (gas discharge tubes, CRTs). It doesn't really say anything about the operation of vacuum tubes, their advantages, or disadvantages. And doesn't even really support its own thesis. The reign of vacuum tubes lasted for less than the reign of the transistor and is in no way unusual in the world of electronics. There are quite a few interesting stories to tell here. Probably the most interesting one is that transistors still underperform vacuum tubes in many respects that would matter to purists, but that don't matter in real life because we learned to compensate for it. Well, except for niche audiophile audiences who don't believe in negative feedback or digital signal processing and want a very linear amplifying component... that they then connect to op-amps, DACs, and ADCs on both sides because that's the only practical way to do it, but there's a performative tube somewhere in between. Another cool story: there were some "integrated circuit" vacuum tubes! |
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| ▲ | cogman10 4 hours ago | parent | next [-] | | There's really not benefits to vacuum tubes pretty much anywhere. The only place I can think of where they are superior (which may not be true anymore) is high power transmission in, for example, radio and radar towers. In all other applications transistors will be superior. Especially because any problem from a transistor can be fixed by adding more transistors until the problem is gone or imperceptible. The audiophile purists are using pseudo-intelectualism to justify a superiority complex. They frequently fail double blind tests whenever push comes to shove. The most famous example of this was them being incapable of telling the difference between a coat-hanger and a premium cable. | | |
| ▲ | aidenn0 6 minutes ago | parent | next [-] | | > There's really not benefits to vacuum tubes pretty much anywhere. The only place I can think of where they are superior (which may not be true anymore) is high power transmission in, for example, radio and radar towers. Tubes are still fairly common in 62 dBm HF ham amplifiers, but solid-state amplifiers are available now, so it's only a matter of time there. > In all other applications transistors will be superior. Especially because any problem from a transistor can be fixed by adding more transistors until the problem is gone or imperceptible. This is often, but not always, true. E.g. parallel MOSFETs operating in triode mode are subject to thermal-runaway. > The audiophile purists are using pseudo-intelectualism to justify a superiority complex. They frequently fail double blind tests whenever push comes to shove. The most famous example of this was them being incapable of telling the difference between a coat-hanger and a premium cable. Tube amps often will be audibly different in a double-blind because many of them have high harmonic distortion (as compared to a transistor amp). Most people think this is a Bad Thing, but audiophiles call it a "warm sound." | |
| ▲ | nolist_policy 2 hours ago | parent | prev | next [-] | | The LHC particle accelerator uses klystron tubes for RF amplification: https://indico.cern.ch/event/1559978/contributions/6664488/a... | |
| ▲ | dguest 3 hours ago | parent | prev | next [-] | | Photomultiplier tubes have a solid state counterpart [1] but there's still a lot of use for the vacuum tube version. [1]: https://en.wikipedia.org/wiki/Silicon_photomultiplier | | | |
| ▲ | tempaccount5050 3 hours ago | parent | prev | next [-] | | Eh. As far as instrument amps go, it's not about perfect fidelity. It's about color and distortion. You'd never say "perfectly white lights are the best for your living room." No one actually wants a perfect white light, people want some more yellow in there because it looks better. The goal isn't equal spectrum coverage or whatever. People like the non-linearity of tubes and that's ok. | | |
| ▲ | cogman10 an hour ago | parent [-] | | The thing is, much like "perfectly white lights" you can mimic the non-linear behavior of tubes with transistor circuitry. On the extreme end you can integrate a DSP into the line to add a "vacuum tube" filter onto the sound in pre-amp. Thinking you can't do that is like thinking all LED bulbs must be 5000k and only incandescent can give that warm glow (Which, funnily that color was chosen to mimic gas lights before incandescents). |
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| ▲ | bregma 4 hours ago | parent | prev [-] | | I disagree. There is nothing in the digitally sampled and modelled world comparable to plugging your guitar into a hot over-driven tube amp and showing the feedback who's the boss. Pure analog transistors don't give that luscious even harmonic distortion and usually just clip like a meth-addled dog stylist in a poodle-grooming station. | | |
| ▲ | n_kr 3 hours ago | parent [-] | | As a guitarist with over 30 years of playing, and owner of many tube and non-tube amps, I disagree. Even experienced guitarist cannot reliably distinguish between transistor and tube circuits in a blind test. Having said that, if only the knowledge of playing a tube amp gives someone a better experience, even if its not empirically distinguishable, thats a perfectly valid reason to prefer it. | | |
| ▲ | utopcell 3 hours ago | parent [-] | | Minor correction: An experienced guitarist cannot distinguish between "captured" amps, or amps which at their core simulate vacuum tubes at the software level. I definitely can't tell the two apart. However, I believe it is easy to distinguish a pure vacuum tube-based circuit from a JFET/MOSFET-based one. There do exist vacuum tube replacements like the AMT 12AX7WS [1] or Jet City's RetroVales [2], but I would argue that the fact that they try to emulate tubes via transistors is a strong indicator that the natural circuits for both sound distinct enough for guitarists. [1] https://amtelectronics.com/new/amt-12ax7ws/ [2] https://web.archive.org/web/20190803060713/http://www.robert... | | |
| ▲ | cogman10 an hour ago | parent [-] | | Not who you are responding to, but I'd say the point I was making wasn't that the sound wasn't different (though, the differences are almost certainly not large enough that most people can tell the difference). But rather that if that exact sound profile is desirable, it's easy to reproduce with transistors alone. The two products you list are proof of that. |
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| ▲ | GuinansEyebrows 2 hours ago | parent | prev [-] | | a non-trivial portion of the guitar-amp world is still very much set on tubes, even as amp simulators get closer to "the real thing". a cool recent development i've been following is the Octal by Verellen Devices (created by an awesome musician who also built some highly coveted boutique all-tube amps): https://www.verellendevices.com - it's basically designed to replicate the push/pull of power tubes in a solid-state package to push extremely loud guitar cab speakers. they seem to impart their own sound signature but still sound really really good, especially compared to a lot of solid-state guitar amps. |
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| ▲ | rexthonyy 2 hours ago | parent | prev | next [-] |
| I studied vacuum tubes back when I was in school. What a fascinating thing, the physics of it. It was a cool tech for its time but there is no way they could match the speed of the transistors that followed, it is just physically impossible, but still, it is nostalgically cool. |
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| ▲ | HPsquared 4 hours ago | parent | prev | next [-] |
| They are robust in their own way. Resistant to radiation, EMP and static electricity. Just don't drop them. |
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| ▲ | dude250711 5 hours ago | parent | prev [-] |
| Western Electric revives U.S. vacuum tube manufacturing at AXPONA 2026, showcasing 300B and 308B amps and plans for new 12AX7 production: https://www.ecoustics.com/news/western-electric-axpona-2026 |
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| ▲ | adrian_b 5 hours ago | parent | next [-] | | Interesting. While I agree that for a powerful audio amplifier the only good choices are either a state-of-the-art switching amplifier made with gallium nitride transistors or an archaic amplifier with vacuum tubes (while the intermediate historical technologies between these 2 extremes are obsolete), unfortunately it is very difficult to indulge in the latter choice, when the prices of good vacuum tubes have become orders of magnitude greater than in their heyday, e.g. at your link the price for a matched pair of WE300-B is $1500 and for a matched quad $3100, while the price of a complete ready-to-use amplifier is too ridiculously high. | | |
| ▲ | boring-human 5 hours ago | parent [-] | | Not to mention the cost of the gold-plated audiophile cables to wire it... | | |
| ▲ | adrian_b 4 hours ago | parent [-] | | Vacuum-tube amplifiers are not in the same class with techniques that are unlikely to have any perceptible influence on what you hear. Among amplifiers that are not perfectly neutral, vacuum-tube amplifiers subjectively seem more pleasant. Moreover, while an electronic audio amplifier made with modern components can be made perfectly neutral when terminated on a resistive load, i.e. it can reproduce any input signal without any changes except amplification at its output, once you connect loudspeakers at its output the amplifier-loudspeaker chain is no longer neutral, i.e. it no longer has a flat transfer function between the electrical input and the sound output and it is not at all clear which should be the output impedance of the amplifier as a function of frequency to ensure the least degradation of the sounds in comparison with the input signal. So it may happen that a vacuum-tube amplifier - loudspeaker system has actually a better overall fidelity than a typical audio amplifier that was designed to demonstrate a much higher fidelity on a resistive load (because thus the transfer function is easy to measure and correct, unlike the complete transfer function to sounds). In theory, one could make a modern amplifier reproduce any quirky behavior of vacuum tubes, e.g. a higher and frequency-variable impedance or certain kinds of distortions, but usually nobody bothers to do this, because it would be expensive and the normal amplifiers are good enough for the majority of people. | | |
| ▲ | Animats 3 hours ago | parent | next [-] | | > Vacuum-tube amplifiers are not in the same class with techniques that are unlikely to have any perceptible influence on what you hear. Yes, they are. The Carver Silver 7 was built to demonstrate this. [1]
It's a tube amplifier with 38 tubes per channel that costs $17,000.
It has all the important features - weighs 68Kg, vibration damping mounts,
takes four minutes to power up, and the wiring is silver.
Gets good reviews from the High End crowd. Then Carver built the Silver 7 T, a transistorized amp with the same transfer function. As a demo, the Silver 7 and the Silver 7 T can have their outputs differenced, or wired up to cancel and drive a silent speaker. Same output. Gets terrible reviews. [1] https://hometechnologyreview.com/CARVER-SILVER-SEVEN-MONO-VA... | | |
| ▲ | adrian_b 3 hours ago | parent [-] | | This is exactly what I have already said. Typical transistor-based audio amplifiers are different enough from traditional vacuum-tube amplifiers, but when the cost does not matter it is possible to design transistor-based amplifiers that are equivalent with vacuum-tube amplifiers. The example given by you shows that there are indeed many people who do not truly perceive the differences or non-differences, so they judge based on prejudices. Of course, I agree that there are many such people and the gold-plated cables were intended for them. I agree that they must exist also among the customers buying vacuum-tube amplifiers. |
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| ▲ | globnomulous 3 hours ago | parent | prev | next [-] | | > It is not at all clear which should be the output impedance of the amplifier as a function of frequency to ensure the least degradation of the sounds in comparison with the input signal. > So it may happen that a vacuum-tube amplifier - loudspeaker system has actually a better overall fidelity than a typical audio amplifier that was designed to demonstrate a much higher fidelity on a resistive load (because thus the transfer function is easy to measure and correct, unlike the complete transfer function to sounds). I don't know the electrical engineering at all, but I thought that this was a solved problem -- or that the degradation and mismatch were effectively negligible, well below the point of inaudibility. | |
| ▲ | robotresearcher 3 hours ago | parent | prev | next [-] | | >In theory, one could make a modern amplifier reproduce any quirky behavior of vacuum tubes, e.g. a higher and frequency-variable impedance or certain kinds of distortions, but usually nobody bothers to do this Don't almost all transistor guitar amps do this? | |
| ▲ | WalterBright an hour ago | parent | prev | next [-] | | In related news, replacing stock parts on your engine with chrome plated ones makes your car race-ready. | | | |
| ▲ | boring-human 4 hours ago | parent | prev [-] | | > Vacuum-tube amplifiers are not in the same class with techniques that are unlikely to have any perceptible influence on what you hear. I don't disagree. Not in the same class, but the audience overlaps. > one could make a modern amplifier reproduce any quirky behavior of vacuum tubes, e.g. a higher and frequency-variable impedance or certain kinds of distortions, but usually nobody bothers to do this, because it would be expensive In other words, the willingness to pay for OG tube amplifiers exceeds the willingness to pay for the sound thereof. I'm not sure you disagree with me either. | | |
| ▲ | adrian_b 3 hours ago | parent [-] | | As a child, I have used some very good vacuum-tube audio amplifiers, which had been built by my father, at a time when they were still the cheapest solution, instead of being a luxury product. They were excellent, so I feel nostalgia remembering them, and I would like to experience again listening through such an amplifier. Nevertheless, if I had so many thousands of $ to spare, I would rather buy some memory modules ... :-( When I was young I made a few unusual transistor power audio amplifiers, e.g. with the output transistors biased in class A and designed for high output impedance instead of low output impedance. I was very satisfied with their sound and some of them resembled more some vacuum-tube amplifiers than typical transistor-based audio amplifiers. However, despite their high audio quality they would have been completely impractical as commercial products, because they needed very big power supplies and they produced an enormous amount of heat. Semiconductor devices are much more difficult to cool than vacuum tubes, for the same amount of heat (because the temperature limit for the former is much lower than for the latter). Nowadays, switching amplifiers can cover all the audio bandwidth with excellent energy efficiency. With an appropriate combination of linear and non-linear feedbacks, one could reproduce both the distortions and the output impedance of vacuum triodes, to make an amplifier hard to distinguish from true vacuum-tube amplifiers. |
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| ▲ | drfuchs 5 hours ago | parent | prev [-] | | Kind of astonishing that they managed to retain the institutional / folk knowledge to be able to create a new vacuum tube product, never mind the machinery and inputs to manufacture them. | | |
| ▲ | Aurornis 5 hours ago | parent | next [-] | | There have been multiple companies coming back to try to make small batches of vacuum tubes. It’s not a mysterious process that depends on arcane knowledge. It does require some tooling and process refinement, but the only real obstacle is getting enough demand to pay off the investment in tooling and process refinement. | | |
| ▲ | cogman10 4 hours ago | parent [-] | | It's basically the same process as making an incandescent lightbulb. Which is why vacuum tubes took off in the first place. It's more parts and more metal working, for sure. But really it's shaping and dealing with thin films and a vacuum chamber. The hard part is precision. |
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| ▲ | mezzman 5 hours ago | parent | prev | next [-] | | Dalibor Farny is a great example of bringing nixie tubes back into existence purely by determination and deep research.
https://www.daliborfarny.com | |
| ▲ | ErroneousBosh 5 hours ago | parent | prev [-] | | In the 90s China bought the whole Mullard factory and shipped it over from England. If you buy cheap Chinese valves, you're buying Mullard ones which seem to be made to a higher standard than they ever managed in the 80s. Any two random EL34s out of the box will be a closer match than the crazy expensive "super matched pairs" that we used to buy. |
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