The Surprisingly Long Life of the Vacuum Tube

ssurprisetalk 1 day ago 18 commentsRead Article on construction-physics.com

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chromacity•about 2 hours ago

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 it just doesn't matter 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 supremely 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!

cogman10•about 1 hour ago

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.

bregma•about 1 hour ago

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•35 minutes ago

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.

tempaccount5050•28 minutes ago

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.

HPsquared•44 minutes ago

They are robust in their own way. Resistant to radiation, EMP and static electricity. Just don't drop them.

dude250711•about 3 hours ago

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

adrian_b•about 2 hours ago

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•about 2 hours ago

Not to mention the cost of the gold-plated audiophile cables to wire it...

adrian_b•about 2 hours ago

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.

drfuchs•about 2 hours ago

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•about 2 hours ago

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•about 1 hour ago

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.

mezzman•about 2 hours ago

Dalibor Farny is a great example of bringing nixie tubes back into existence purely by determination and deep research. https://www.daliborfarny.com

ErroneousBosh•about 2 hours ago

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.