Smothing signal (similar way to vacuum tubes, analog)

[k brown]

Plus a lot of the 'smoothness' of vintage gear hasn't anything to do frequency response, but alterations of transients - especially in the case of transformers (core saturation effects, etc.). A combination of slightly slowed transients and an increase in second harmonic distortion (which is euphonious) is a lot of what people hear as the 'smoothness' of tube audio.

For example, I built a tube microphone preamp based on a very old Pultec line amp, but I left out the input and output transformers because my application didn't require the functions they provided. It produces the cleanest, clearest sound of any mic pre I've tried. So, the famous 'tube sound' isn't necessarily inherent in vacuum tubes themselves; used in a properly designed circuit, and within it's design parameters, they are very linear devices.

[tulamide]

What tubes added to the sound (well, at least what nowadays is said they added), is warmth. This warmth is nothing else than a mild distortion, as others already said (harmonics are added). I'm working with Cakewalk and each track there has a channel strip. One of the tools in there is tube emulation. Call me ignorant, but I don't hear a difference, unless I put it to the highest level, where it is just a simple and subtle distortion.

I don'T think tube emulation is worth it!

[Spogg]

Someone once said that a perfect amplifier is a piece of wire with gain.

In other words the signal path should ideally not change anything in the waveform. What I think some people crave is the colouration produced by imperfect technology. But when that technology was current, engineers strived to eliminate that colouration.

I’ve never really understood this hankering for old sound quality myself. I have to assume that it’s some type of nostalgia and/or fashion. Taken to its extreme we might one day see an advert for a new plugin that proudly boasts that you get authentic random clicking when you move the mouse.

I’ll stop now.

[tektoog]

I think it has also to do with what's callled "listener fatigue"...
Human ear is not made to listen to perfection, pristine sound for hours...
That produces that phenomenon called "listener fatigue"...
Same debate has been going on since the CD release back in 1987 I think it was....
And that's maybe an explanation for people looking for to get a warmer sound that the crystalline sound that comes out of a 96khz state of the art today's soundcard... But I agree that leads to what's called cognitive dissonance... I'll buy the best gear out there, just to alter it and get a worse sound that I was producing with my 4 track recorder back in 1991...
Same deal with plugins that emulates records scratches, or tape recorders... I personally don't get it... but hey...
Why not

[martinvicanek]

There is certainly a lot of myth and religion around tubes. Like the previous posters, I often wonder why people would want to emulate in detail the imperfections of old days equipment, having available a far superior and even cheaper technology today. On the other hand...

As a teenager I had a Gison Les Paul guitar and a Vox AC30 amplifier and, yeah, when I cranked up the volume, suddenly the world seemed a much better place! Today I can get a reasonable solo guitar sound with a soft distortion and some pre/post filtering. Plus a whole lot more sounds which I didn't have back then.

So yeah, maybe a bit of nostalgia there.

[k brown]

Well, there are two very tangible and audible differences between tube and solid state, especially when it comes to power amps. It's a lot easier to design a low-distortion tube circuit than an equally low-distortion solid state one. It takes a good deal of engineering know-how, and more complex circuitry to get THD to low levels with solid state devices, whereas a fairly simple tube circuit can be quite low. The other factor is the fundamentally different way that transistor circuitry clips - it tends to generate more THD (and a lot of ugly in-harmonic distortion) just below clipping, then clips suddenly and with nasty-sounding hard edges to the clipped waveforms. Tubes tend to generate much less THD (and that, mostly euphonic second harmonic distortion) just below clipping, then clip more gradually and with softer, rounder edges to the clipped waveform, until the clipping gets to gross levels. As a tube amp approaches clipping, the sound starts to become rather benignly compressed; as an average SS amp approaches clipping, the sound becomes rather ugly. So a sufficiently well-engineered SS device can sound as good as tube (as long as it's kept well below clipping), in most cases, and in average use, they tend not to.

A lot more than mere nostagia going on.

[tulamide]

I think that things are starting to get mixed together in an unfortunate way.

I don't know how tubes might have colored the signal (thanks for the word, Spogg, it makes total sense and I wasn't aware of it), but we should seperate the analog and digital domain. The latter knows no tubes, they can only be emulated. In this field there are seperate applications. A tube emulation that's supposed to mimic the behaviour of old analog mixing consoles, and tube emulations used to amplify and distort sound (e.g. Guitar).

I was talking about the former, and I repeat that the tube emulation (you can set it in Cakewalk to certain names, like Neve, but I don't know those old mixing desks) doesn't color the sound. There is no added warmth, no noticable change in the sound. It's just eating CPU.

So, what I'm saying is, that an emulation of tubes for the purpose of slightly coloring your sound is not worth the effort. It might have its worth in analog mixing consoles, but that was not the topic.

[mayo]

why smoothing is necessary when emulatig hardware and for perfect sound? Digital sound is perfect, detailed but many transients creates harshness at high volumes, after limiting etc. I have 12 years of experiences with music production, mixing, mastering and I know that many analog devices smoothen signals , reduces transients and make them softer, smoother, rounder - then sound is pleasant for ears, less sharp, less harsh

unfortunatelly basic saturation algorithms do not create same thing as analog devices and vice versa creates more distortion, harshness artifacts

I have also electrotechnical education and I know that transformers, vacum tubes smoothen signal, one of reasons is that signal goes thru "air" not wires, in vacuum tube signal goes thru air or vacuum as emmited electrons and in transformers as electromagnetical signal, so these things are not connected with wires and oldskool transformers and tubes smoothen signal lil bit

[k brown]

Air vs wires? ..--umm, no.

[martinvicanek]

The other factor is the fundamentally different way that transistor circuitry clips - it tends to generate more THD (and a lot of ugly in-harmonic distortion) just below clipping, then clips suddenly and with nasty-sounding hard edges to the clipped waveforms. Tubes tend to generate much less THD (and that, mostly euphonic second harmonic distortion) just below clipping, then clip more gradually and with softer, rounder edges to the clipped waveform, until the clipping gets to gross levels. As a tube amp approaches clipping, the sound starts to become rather benignly compressed; as an average SS amp approaches clipping, the sound becomes rather ugly.

Yes, I agree, and that is the origin of the prejudice that solid state amps are no good for guitar (or bass). Of course you can use solid state circuity to implement a soft distortion (germanium diodes for example). But once people are convinced that solid state sounds crappy, they are stuck with it.