Can tube DSP substitute for tube amps?

[PongPoku]

DSP filters are becoming better at reproducing tube amps.

I am sure that lots of people who already invested a lot of time, money, and energy into tube ecosystem will not settle with tube DSP filters.

But, free open-source DSP filters can perhaps stand in the place of tube amps for casual music listeners who are not fussy about particular details.

This is great for miniaturization of devices. One can just enable tube effect in smartphone or computer.

What do you think? Are tube DSP filters good enough for casual listeners?

[merlyn]

Hi PongPoku, and welcome to the forum.

You're getting into hi-fi audiophile stuff there. Audiophiles are generally well known for being a bit nutty, and dare I say ... gullible. Like the Russ Andrews £2000 mains cable.

There is a technical basis to some of these ideas, but audiophiles don't seem to understand the technicalities, and get ... eh ... conned. Confirmation bias comes into this, and I do believe that audiophiles hear a difference. But it's not there, and in blind A-B tests, nobody can tell the difference between a decent mains cable and a £2000 one.

The technical basis of valves (tubes) is that a class A valve amp allows the second harmonic (an octave) to be introduced. This is generally considered a musical type of distortion. But it is distortion, which seems at odds with the idea of 'hi-fi'. So a DSP valve is introducing valve characteristics on top of the characteristics of the solid state system that is being used.

But if it sounds good to you -- if it 'warms up' the sound, then go for it.

[PongPoku]

People often use software sound effects to color the sounds.

This is better than paying a lot of money in the tube ecosystem.

I agree that just adding even order harmonic distortions through software DSP is likely to be sufficient for the purpose of adding tube-like sound.

Precise emulation of tubes is not necessary.

If I don't like even order harmonic distortions, then I can just disable the sound effect and enjoy HiFi.

[PongPoku]

Hi PongPoku, and welcome to the forum.

You're getting into hi-fi audiophile stuff there. Audiophiles are generally well known for being a bit nutty, and dare I say ... gullible. Like the Russ Andrews £2000 mains cable.

There is a technical basis to some of these ideas, but audiophiles don't seem to understand the technicalities, and get ... eh ... conned. Confirmation bias comes into this, and I do believe that audiophiles hear a difference. But it's not there, and in blind A-B tests, nobody can tell the difference between a decent mains cable and a £2000 one.

The technical basis of valves (tubes) is that a class A valve amp allows the second harmonic (an octave) to be introduced. This is generally considered a musical type of distortion. But it is distortion, which seems at odds with the idea of 'hi-fi'. So a DSP valve is introducing valve characteristics on top of the characteristics of the solid state system that is being used.

But if it sounds good to you -- if it 'warms up' the sound, then go for it.

After watching Not all distortion is created equal (saturation and harmonic distortion explained), it seems that distortions added by playback devices are generally undesirable, but even order harmonic distortions are less undesirable than odd ones in general.

Early solid state amps produced a lot of odd order harmonic distortions and produced hard clippings when they were overloaded. Tube amps produce more of even order harmonic distortions and produce soft clippings. That's why tube amps sounded better than solid state amps when solid state amps were in early stages of development. Nowadays, solid state amps are virtually transparent. Transparent sound is still better than unintended even order harmonic distortions which sound better than unintended odd order harmonic distortions.

Tube amps aren't better. They are just different. Even order harmonic distortions and odd order harmonic distortions can both be used as effects in production.

In general, it's better for playback devices to not add audible distortions. Distortions intended during production are okay.

[merlyn]

There is a bit more to it. Valves can handle high currents, so for a power amp this could mean it handles transients better, transients being the very high levels at the start of notes or percussive hits. To get a 'transparent' sound a transistor amp needs a lot of headroom, headroom being the difference between where the signal is and the maximum possible signal. Some solid state hi-fi amps are 450 Watts per channel, which isn't so they go deafeningly loud, but so that there is a lot of headroom. E.g. the McIntosh 462

A valve version is the 1502, and it is 150 Watts per channel, showing that valve and transistor Watts are not the same.

Given that they both cost about £15000, what they sound like is a bit of a moot point, certainly for me.

[PongPoku]

Cheap class D amps can handle transients by having a lot of headroom, but they can't dissipate a lot of heat because they just have small heatsinks in metal cases. They can't actually sustain a lot of power over time without too much heat. They can actually deliver a lot of power for a brief period of time. More expensive class D amps may have better heat dissipation capabilities with better metal cases that serve as large heatsinks.

For near-field listening, I consume less than 10 watt per channel. My class D amp along with the power supply sold with it can handle up to 77 watts at 4 ohm and 48 watts at 8 ohm without distortions. If it is given a more powerful power supply, it can handle more watt.

I don't know whether this provides enough headroom, but for the vast majority of the time, I consume less than 1 watt. I doubt that I actually consume more than 1 watt. But, I just assume I consume less than 10 watt per channel.

Recent class D amps just need better heat dissipation for sustained load. Near-field listening doesn't require sustained load.

[bluebell]

Valves can handle high currents

Valves can handle high voltages, that's why they need output transformers translating high voltage and low current into low voltage and high current for standard 4Ω or 8Ω speakers.

Transistors can handle high currents.

Valves have – especially together with output transformers – sexy distortion and saturation effects pleasing our ears.

[PongPoku]

Valves have – especially together with output transformers – sexy distortion and saturation effects pleasing our ears.

I figured out that tube amps produce asymmetric saturation which is often called tube saturation. Asymmetric saturation produces more even harmonics than odd harmonics. However, asymmetric saturation also produces intermodulation distortions which are always undesirable.

DSP plugins can easily simulate asymmetric saturation. Thus, you don't strictly need tube amps if you just want asymmetric saturation. Asymmetric saturation is only one aspect of tube sound, but that alone is good enough for people who want tube warmth. To get tube sound stage, one also needs to simulate non-linear frequency response of tube amps. Non-linear frequency response is less versatile than asymmetric saturation. Thus, I'd stick to linear frequency response of solid state amps.

I wonder whether tube saturation DSP plugins can insert even hamornics without much of intermodulation distortions and odd harmonics.

[PongPoku]

I found https://github.com/hannesbraun/airwindows-lv2

airwindows-lv2 tube2 plugin is the perfect way to add tube saturation to pipewire or jack.

Asymmetric saturation is just one aspect of tube sound, but it is the primary reason that people like tube sound.

If you want the real tube sound, then tube2 may not satisfy you.

But, tube2 can save a lot of money you were going to spend on tube equipments if you just want tube saturation.

I'm personally going to add tube2 to pipewire and forget about tube amps. I can fiddle with tube2's parameters and selectively point applications to it. It is more flexible and more convenient than real tubes.

It doesn't simulate every aspect of tubes, but it captures the essence of tube sound.

[PongPoku]

Does anyone else prefer airwindows-lv2 tube2 plugin to actual tube amps for convenience, flexibility, versatility, and cost savings?

When a piece of software captures the essence of a class of hardware, then I don't feel the need to buy the hardwares.

An example is retro game console emulators. I don't play games, but I would not buy retro consoles because there are nearly perfect emulators.

I'm pretty sure that people whose survival depends on selling or marketing tube amps will hate me for saying this. They don't care about truths. They just care about their own survival.

[Michael Willis]

I'm pretty sure that people whose survival depends on selling or marketing tube amps will hate me for saying this. They don't care about truths. They just care about their own survival.

That's not necessarily the case. They just require customers that disagree with you. There are still plenty of people who believe that digital emulation will never match the sound of a tube amp, and they are willing to pay for it.

[PongPoku]

That's not necessarily the case. They just require customers that disagree with you. There are still plenty of people who believe that digital emulation will never match the sound of a tube amp, and they are willing to pay for it.

They would still hate me because people are affected by voice, and I'm making my voice on the internet.

Just being informed of alternative options can reduce influx of new customers in the long run.

Tube sound is just different. It's not objectively better. If a digital sound effect captures the essence, then most may settle with the digital version or prefer it to real tube sound. Think of it as a software tube preamp that is reliable and consistent. It doesn't change over time. It doesn't require aging. It doesn't require maintenance. It doesn't require payment. It doesn't require extensive research before you can make it sound good. You can tweak its parameters easily. You may or may not like the sound. If you don't like the sound, just turn it off. Ditch it. There is no waste of time, money, and energy.

In most cases, people just want to sprinkle some even harmonics to their music. Tubes are not required for that. Software can do that.

That was my sales pitch.

[bluebell]

I'm pretty sure that people whose survival depends on selling or marketing tube amps will hate me for saying this. They don't care about truths. They just care about their own survival.

That's not necessarily the case. They just require customers that disagree with you. There are still plenty of people who believe that digital emulation will never match the sound of a tube amp, and they are willing to pay for it.

Hardware is sexy. I like Guitarix very much but I like my little Hughes&Kettner TubeMeister Deluxe 20, too.

[merlyn]

Valves can handle high voltages, that's why they need output transformers translating high voltage and low current into low voltage and high current for standard 4Ω or 8Ω speakers.

The way I look at an output transformer is that it changes the impedance from the high impedance of a valve, to the low impedance required to drive a speaker. Effectively that is the same thing as saying the transformer changes the output from low current/high voltage to high current/low voltage.

Transistors can handle high currents.

Maybe worth saying big transistors with big heatsinks can handle high current. Silicon gets hot.

What I was getting at was that valve Watts are subjectively louder than transistor Watts. In addition to distortion there is a compression like effect from valves. This means transients are smoothed out. Again, absolutely not hi-fi, but subjectively more plaeasing to the ear.

I was in a band with a guy who had an all valve (even the rectifier!) Mesa-Boogie Lone Star. It had a switch to put it into 5W class A mode. I have a 250 W solid state amp. Subjectively they were in the same volume ballpark, both with a clean sound.

[PongPoku]

Hardware is sexy. I like Guitarix very much but I like my little Hughes&Kettner TubeMeister Deluxe 20, too.

Hardwares look sexy because manufacturers want to sell their hardwares. Somehow, guitar amps look sexier than most women. The manufacturers really have perfected the look. It's hard to resist when you look at them. But, it's also a form of mind control. Mind control sells. Psychologists have learned how to manipulate human mind. You can create power differential by wielding psychology against people. Marketing is applied psychology. Psychology can be weaponized. You have to be careful with visual symbols which can program your mind easily. They can make you buy things you don't need. They can also make you believe lies. Tube amps consist of a set of powerful visual symbols that are hard to resist if you are not aware.

If you want sexy things in your room, you can buy fancy interior decorations.

My tiny class D amp doesn't stand out. It looks brutal. My big computer case looks brutal and makes me unhappy. Thus, I may add fancy decorations to my room.

If tiny class D amps perfect visual symbols, they can sell a lot as well.