I just LOVE letting my mind wander wander wander. (One second while I watch the magnetically-repelled train goes by at 80 mph, blowing silently, and just barely missing the bamboo in my back yard … and the eggs on top of it are still upright in their golden cages!)
So what about tubes? Are they really “warm” sounding, Or am I hearing heat because a tube is hot? Well look out … I’m not sure we know the whole story about tubes vs. transistors, unless we pull more of the picture in …
Warmth, the way Rupert N. describes it, has less to do with a particular sound than the feeling you get FROM that particular sound. He remarked once in a little speech he gave to a group of SPARS members in NY, that in a blindfold test of different recordings, a large percentage of the listeners actually relaxed their shoulders and settled back in their chairs when he swapped their listening from a transistor based system to a tube based amp. And he remarked loudly that THIS is what he is referring to when he says warm. Warm like a hug, or warm like seeing a long lost GOOD friend. NOT “fatter”, like I’ve heard, or “punchy” like I’ve heard. but warm. Like a baby wrapped in bear hide.
And he goes on to say that as a tube is driven harder and harder toward “saturation” level, it is the even order harmonics, particularly the second harmonic, that is the taking over in this warm, “addictive” sound. (Those are his words!)
I myself have fooled myself many times by thinking I was contributing to the “Fatness” or the “Punch” of certain instruments or recordings by using tube gear, when in fact, in a careful A/B comparison, I was usually simply adding gain. EVERYTHING sounds better when it’s a bit louder, right? Almost every tube device uses fairly good sized transformers in order to isolate the higher voltages needed to power up a tube, as well as matching the impedances of different “things” to the impedance of the tube amp. And these transformers are on outputs as well as inputs, meaning most audio has been through at least 2 transformers. AND I DO hear a fairly obvious difference in the sound of a piece of gear such as a Fairchild 670 or 660, as well as other tube gear. But the sound does seem to lessen as the amount of input comes down. So what am I hearing? Tubes used to be considered as pristeen amplification in, say, McIntosh stereo amplifiers. And Dynaco amps. So what AM I hearing?
Theory One ties together the magic “3”. Tube Saturation, Magnetic core saturation and Magnetic tape saturation.
There are 3 processes that a wagonload of today’s music never gets the chance to see. And to know!! Tape, core, and tube saturation. These 3 things have something in common. Do you know what those 3 things are? If you guessed the word “saturation”, well then by golly you are right! If you apply too much signal to a tape recorder, the tape will get saturated. Ditto for a tube. And ditto for a transformer! Saturation means only this. “OK! Come on back … a little more … a little more … almost… one more … WHOAAAA.!!! ” That is saturation. It will be a faithful reproduction from the tape as long as it doesn’t violate the saturation point. After that, you may very well give it more and more and more, but the output is going to stop and remain the same if you go beyond that saturation point. AND, yes, technically you have made that channel into a limiter! THAT is the sound that people like on music. It IS something that we don’t add very much of any more. But it is that classic sound that most of you have heard at some point, usually in your youth, and certain sounds, certain songs survive very warmly in a place near saturation. As opposed to what many describe to me as a “harsher” sounding digital recording.
Any time you have a wire wrapped around steel, you have a magnet. An “electromagnet”, more or less. The more electrons, current, volts … whatever you call it, when it gets louder going in, it SHOULD get louder coming out. BUT …. there is a point, called “core saturation“, in the case of a transformer (or even a tape recorder’s head!), tape saturation, in the case of magnetic tape, and tube saturation, in the case of a tube. This last case is what most guitar players like about various guitar amps. Man tends to gravitate, it seems, toward the saturation thing more than the digital thing. But what is it exactly that makes man seem to “prefer” this analog stuff over digital stuff? Before we go on, I am talking about a very unique few people on the planet who notice much, if any, difference. They generally are not listening like an engineer listens. Yet I believe to MY saturated core that MAN as a being, tends to, honestly, prefer the analog sound … somehow. So… Theory One, the belief that there is a physical thing that you can touch and measure called saturation, and it has been with us almost since the beginning of recorded sound; that is is slowly being replaced by a completely different set of rules we call “digital” recordings; Theory One takes us right up to … Theory two… which is next!