Myth: Amplifiers based on vacuum tubes sound better than solid state designs, and a good tube preamp can even restore clarity and warmth that has been lost in the digital recording process.
Fact: Both types of amplifiers can have a frequency response flat enough for audio reproduction. But modern solid state amplifiers have measurably lower distortion than any tube-based design. Most tube-based power amplifiers also require an output transformer, which increases distortion - especially at the frequency extremes. Further, solid state power amps always have a better damping factor.
Many people - including me - like the sound of tubes, especially in a good guitar amp.
Even if you prefer the sound of tubes, please understand they simply cannot restore any quality that was lost earlier in the recording process. All a tube preamp can do is add an effect that you may find pleasing. Studio monitor amplifiers should never have a "sound;" if they do, they are in error. Tube circuits can affect the sound in a way that is similar to analog tape recorders, and you may in fact find that pleasing. I won't dispute that even-order distortion can sound good, by adding overtones that are richer than odd-order distortion, which is, musically speaking, dissonant fifths. However, all distortion adds intermodulation (IM) products that are not harmonically related to the source material, and are thus decidedly non-musical.
As we have come to learn with Ethan's posts
, there is much truth in what he writes, though the conclusions based on those truths are sometimes suspect–occasionally just wrong. Let's take a look at several of these often believed quotations.
"Studio monitor amplifiers should never have a "sound;" if they do, they are in error
." Well, that's nice to say and makes sense. Only, it's inaccurate. All amplifiers impart a sonic signature; some more, some less–as do the other tools of recording engineers, from microphones to loudspeakers. Of course the ideal would always be to use amplifiers, microphones, monitors, wiring and recording apparatus that are sonically neutral. The problem is, they do not exist.
"...tube amps simply cannot restore any quality that was lost earlier in the recording process. All a tube preamp can do is add an effect that you may find pleasing
." This is a very common myth - and a carefully written one at that. The author is 100% correct that nothing can restore that which has been lost. It is for this very reason we cannot restore MP3 and lossy files to their original splendor. Once lost, forever gone. But it is to the second sentence where we have our differences.
"All a tube preamp can do is add an effect that you may find pleasing
." Poppycock. I have numerous examples of circuitry, both tube and solid state, that hide information less than other configurations. And this is a point I try to help people understand. Great circuitry does not bring out more information, instead, it hides it less. And therein lies a big difference.
I recall the first time I listened to DirectStream playback a CD. One of my coworkers mistook the playback for high resolution (we had both a CD and high resolution copy on the server of that track). He was right! For the first time, it was evident the gap between CD and high resolution audio had been nearly closed–and not because DirectStream revealed more–but because DirectStream hid less.
So, the next time you listen to kit that uncovers missing details, remind yourself that your previous reference had been hiding it, not the opposite.