what makes vacuum tubes the better choice for some application (most notably an amp for music) over more modern options?
In: Engineering
When it comes to amps, vacuum tubes are analog and as such tend to have a more pleasing sound to the human ear even as they distort at higher volumes. Transistors tend to be louder and crisper at high volumes.
Also being analog they don’t suffer any losses or distortion from an analog to digital (and back to analog) conversion.
IIRC the distortion from tubes (and components that they require, such as transformers) is mostly even harmonics that are more pleasant to the ears than the odd harmonics from transistors (even harmonics are the same tone played one, two, three… octaves higher, and that probably makes them closer to the natural harmonics produced by the instruments).
OTOH with transistors and ICs you can produce essentially distortion-free amplification and add your own mix of even harmonics.
So a good deal of this is a matter of personal taste and a bit of hype.
It is a matter of personal preference. Objectively (ie measured by instruments) modern solid state or digital amplifiers can be designed with much lower total distortion and background noise of an audio signal relative to vacuum tube amplifiers. Distortion here being a measure (ELI5) of the accuracy the output signal matches the input signal.
But vacuum tubes amplifiers tend to distort in what can be perceived as pleasant – giving a “warmer” or less “clinical” sound. Very high quality and low distortion sound equipment can give music a sound of “distinctness” that some people think as too cold and separate especially if they’re not used to it.
A tube is not an equalizer.
If you compare a solid-state amp and a tube amp in a high-gain setup (heavy metal eg where tube amp is the king), the differences are minimum.
Changing the amp’s _speaker_ and/or mic positioning will give you more radical results rather than changing the tube(s) in your amp.
Nowadays a lot of touring musicians are changing their setups to solutions like Kemper, since tube amps are bulky, fragile and expensive. Technology has gone a long way since the first amp sims.
For guitar amplifiers, the distortion is the point. The best way to think about it is that the amp isn’t there to make the guitar louder, it’s an integral part of the instrument. The guitarist plays the amp as much as the guitar to get the sound that he wants. Tubes distort in pleasing ways to make sounds for electric guitar. You can accomplish much of the same using a pedal board, but overdriving tubes was how it was originally done.
Sorta another way of looking at this. Our world when you dig into it is near infinite complexity. As we attempt to approximate the world as precisely as possible, we end up smoothing over edges that aren’t really smooth. Making things too perfect, like a planned community where all the houses fit together too well. The solution often isn’t trying to make something that approximates better and better until the conscious mind can’t tell the difference, but rather, to let go and let some of the innefficiencies and complexities from a natural system leak into it. The Tube’s have a degree of randomness to them not planned by a computer but by physics which take input from everything in the world around them, and I think these add the complexity our brain secretly craves.
The answers all skew toward audio applications, which isn’t surprising. There are other applications where vacuum tubes are still used, however.
– Radio and TV broadcast. A single (big!) vacuum tube sits at the heart of most high power terrestrial broadcast amplifiers. Transistors can do the job, but it requires a complex network of many components to develop the required power at radio frequencies.
– X-ray. All medical and industrial X-ray sources use a vacuum tube to generate X-rays
it used to be a different sound that was harder to achieve in solid state amps (typically the alternative to tube amps). Now though we’ve gotten really good at being able to emulate stuff. Instead of spending 4x as much on an equivalent tube version of a solid state amp, you can buy a pedal that creates that same “sound”.
IMO,
Instead, what it’s become is kind of a call back to tradition and the “classic” way to build amps, similar to buying older cars. Some people like the concept of being able to see the tubes lit up and creating the sound coming out of their amp.
It’s kind of the same concept as just plugging your guitar into a computer and plugging your headphones in. You can get virtually any sound and effect you want by doing that with software and time. A lot of guitar people, though, want the feeling of actually having all of that amplification/speaker equipment in the room with them that they can actually feel. The sound being pushed, the heat from the amp, etc.
Another thing is people want the amp that created the sound on a specific album/song. Most of the guitars Kurt Cobain used were super cheap or pawn shop guitars. About 10 years ago, you could track these down used for a few hundred bucks. Then they started getting popular in the indie scene. Now the same guitars that used to be $300, are almost $2k cause everyone wants to copy their idols. I think people buy those amps because it gives them hope that they can create something similar.
For me it’s almost strictly a nostalgic motivation to buy tube at this point. It was the first quality amp that I bought and eventually sold. At this point I really want another one but not really because of the tubes but rather so I can get what I used to have.
I had read that tube amps are more suitable for lower amplitudes like record player preamps or headphone amps, the reasoning being that they have a faster response than transistors and therefore make for a more accurate or brighter sonic picture. But that’s only at low volume and it doesn’t scale. I don’t know if this is just audiophile mumbo jumbo or not though.
The reason is because classic designs and variations on them persist forever. There was a time when tube guitar amps were often displaced by solid state designs; the Gibson/Moog Lab Series sold a lot of units, as did the Roland JC series. Peavey solid state amps also sold a lot.
By the 1990s, the rise of Guitar Center and the Internet changed how people saw solid state. Solid state evolved to being entry level amps ( although Sears/Wards and the Crate marque had cheap solid state entry level amps ). People wanted to derive prestige from expensive toys. The number of people who used amps as tools declined.
Guitar players are not all that rational in their choices. But still – many of the better amps are tube. At higher volume, there can be significant sonic differences. Not always.
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