In spite of all the high technology available these days, in the form of computer based audio systems; there are still those boring old gits who insist that a glass tube with a strange collection of bits of metal inside, and all the air sucked out, still makes a better sound than the latest transistor amplifiers.
Of course anyone who has "studied" electronics knows that these old valve circuits have not even a hope of getting the "signal-to-noise ratio" that state of the art kit can achieve. That is of course quite true but to be honest, that also is a bit misleading as I don't know of a single course syllabus that actually covers valve circuits and very few tutors even mention them in passing!
So why is it that guitarists will pay double the price for a monster tower of amps and cabs with valves?

Why would a studio want a valve microphone pre-amp or compressor and not just the latest super microprocessor controlled digital jobby?

Does the "warm sound" have anything to do with the fact that these fragile glass components will take your skin off if you handle them and can chuck out more Watts in heat than sound level?

This is the music business here mate,... nothing is supposed to make sense is it? How can we get a "pure" note out of such old noisy kit? Well that depends on what you call pure I guess.
It's all very well sitting down with a digital editing suite and cleaning up the wavs till they have notes, pure notes and nothing but the notes,.... but have you really improved the sound by doing so, or have you lost something? Theoretical audio is always evolving but the human ear is still the same bit of skin a gristle it always was, so can we really teach such an old bit of kit new tricks? No,.. and to make matters worse, the human ear is not nearly a linear device as far as audio pick-ups go and added to that, it is connected to a very individual filter called the human brain and any guy who has met more than one woman will tell you the brain is not a stable filter at all!
(Actually, that comment cuts both ways doesn't it ladies?!)
It is possible to fool the ear and the brain into where a sound is coming from in space, but most ears will be able to tell the difference between live and studio recordings, depending on how many rock concerts they've been subjected to! The ear is an amazing device all on its own but when you consider the added selective effect that the brain adds to what it "hears", then no other system of audio pick-up can even approach its quality, or its eccentricities.
I still have my collection of vinyl records and no matter how pristine the new CD might be, there is something about the hiss, crackle and other spurious noises that make them special to me. It really has nothing to do with sound "quality" in the theoretical sense, far more to do with the fact that when I first listened to these classics like "Stairway to Heaven", it was on a really cheap and nasty mono BUSH record player cos that's all I could afford thus, the hiss crackle and distortion became a part of the audio experience. Perfect it wasn't but it was, at a mere twelve watts, loud enough to upset the neighbours,.... frequently! More to the point, it was the music I was listening to, not the sound quality. Yes I do have amps now that are silent till driven, put your head in the bins and the first note will make your nose bleed! I also have some really nice digital instruments but there is something about a sound that is less than clinical,.. it is closer to what I hear in the real world. That is where old valve technology scores so heavily, it does distort but when it does so, it actually produces harmonics that are related to the musical scales we play, or listen to so it tends to add something that fits rather than sticking out like a sore thumb.

This is the reason that an old VOX AC30 will sound louder than some modern 100 watt amps, the overdriven valve produces a unique addition to the sound of a guitar that is very hard to accurately "emulate" with any solid state device. The sound Brian May gets out of a wall of these antiques is ample testament to that, quite apart from his own unique talent for making one note do more than many guitarists do with several!
The HAMMOND sound was born in valve state entirely, the little click that accentuated the notes was a function of the high voltages and not a designed in effect. Again, the classic "Whiter Shade of Pale" was done with a Hammond M100 series and nothing quite gets the same feeling, because it also had the same characteristic sound as the amp heads the rest of the band were using. The overall mix was thus producing the same "tuneful" harmonics, giving a wall of noise that was acceptable to the musical ear.
Two other more technical quirks to add to this is to do with the actual voltages that these two technologies operate at. Solid state devices have power supply rails that are quite low, anything from 5 to maybe 30 volts. These voltages are very flat and regulated. If you drive a signal till it manages to reach the supply rail, the top of the signal get very flat with very sharp edges. This has the effect of severe distortion and masses of harmonics, overdriving digital recorders shows this up real quick!
Valve circuits on the other hand have voltages that are above 100 volts and the smoothing is not as acute. The point at which a signal "hits" the anode voltage is softened by the resistor feeding it and that resistor, with the smoothing capacitor, creates a low frequency "time- constant" which tends to round off the edge of the resulting distorted signal, thus the imperfection is not so jagged on the ear. HH in the uk, made a module for their amps that consisted of a series of such filters to get close to a valve sound. Rocket science it aint but it was close, not close enough to put Jim Marshall out of business though!
Ah yes,.. I mentioned heat in passing didn't I? Interesting thing about noise from solid state stuff is that the figures they give you only apply to "bench" conditions usually, which means as soon as the thing gets hot in the rack you crammed it into, the noise gets worse because most components get noisy when hot. Valves on the other hand, are designed to work hot, hence getting a bit warm in the rack aint gonna make the slightest difference is it? The spec will still be just the same as when it quit QA,.. unless you fiddled with it!

And one final point,... stupid I know but if the worst was to happen and some idiot actually did "push the button" to wipe out the world as we know it,... all your super-conductors and high-tech semiconductors will be dead with the first bang. Valves (and beetles)will survive so at least rock music will survive,... even if we don't?

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© PB 2004