Originally Posted by kbmitch
Tubes color the sound. Pure and simple. They add harmonics which give the music a "warm" sound.
Some people say that, but any amplifier that adds harmonics also adds IM distortion products that are aharmonic and generally sound ugly.
Also the various harmonics of a fundamantal are of different orders, occur at different frequencies and all sound different if they are audible at all. Why would they all add warmth?
Some people like this sound
I still remember the days when tubed amplifiers were all we had. They were big, heavy,hot, expensive, and required nearly constant maintenance that was a PITA. A set of tubes were needed every year or two ifyou used the amp all the time, and a set of tubes could cost a serious fraction of the cost of the original piece of equipment. Many o tubes had to optimized to the piece of gear with bias controls, which really had to be done by someone with expensive test equipment. One of their congenital problems was that they all tended to have high source impedances and so their frequency response was audibly affected by the impedance of the speakers they were attached to.
and I have heard some tube enthusiasts touting that this result is the way it was meant to sound.
Their seem to be all kinds of enthusiasts in this world that want you to do as they say and spend your money the way they say.
But they could not be further from the truth. The amplifier or pre-amp should add nothing or take away anything from the original signal. There is no perfect amp but a well designed solid state amp will produce a cleaner, more accurate sound as long as it does not hit the clipping threshold.
That frequently seems to be the case.
At clipping it will add odd harmonics and quickly the music will sound downright awful (not to mention that your tweeters could get fried).
Actually, that is false. The reason why SS amplfiers tend to add only odd harmonics is that they are push-pull amplifiers and push-pull operation tends to cancel out even harmonics. The solution seems obvious - have a power amplifier with enough power that you never clip it!
Tubes, on the other hand, at the clipping point just add more of the same harmonics that are there at low volume levels which adds more warmth
That is false. Many tubed amplifiers are push-pull (balanced output devices) and also naturally cancel out their own even order distortion, and thus produce odd order distortion. I tested dozens of tubed amplifiers on my own test bench back in the days when tubes were all we had. When overdriven the better cleaner tubed amps produced very nice square waves, that were hard to tell from the square waves that were produced by SS amplfiers.
and they start to sing which is why tube guitar amps are frequently preferred. Tubes are great for screaming guitar solos but not really for accurate sound production.
Right, there is a big difference between producing music and reproducing music.
I know that there are going to be some that disagree with me. All in all, it all boils down to this: use whatever sounds good to you and do not let some salesman on commission convince you otherwise.
I shake my head at the thought of people who like the sound of IM distortion. I is not harmonically related to the music and it always sounds nasty to me.