Tube amplifiers sound better due to the euphonic distortions they enhance the music, in addition to lots of other reasons. I’ll cover below. These are subtle effects most audible to musicians and extremely dedicated music lovers; casual listeners (those who “listen” with their eyes open while doing something else) usually won’t notice, but sometimes the main difference is so obvious that people’s wives will comment that “wow, that sounds much better” whenever people use tubes in the home.
Tube amplifiers measure poorly inside the lab specifically because of these added distortions, however, these distortions are often an integral part of what make sure they are sound better. Even today with the all-digital infrastructure from recording studio to SMSL DAC for years and decades and decades have tried tube pre-preamplifiers within the microphones themselves. Today their outputs are fed to tube preamplifiers before being digitised for recording, mixing and distribution. We use tubes given that they make the music we create sound better: smoother, warmer and cleaner.
Ditto for guitar amplifiers found in creating music. The ways that tubes distort when pushed to the edge are much more musical compared to artificial sounds that can come from transistor amplifiers when overdriven. Some transistor guitar amplifiers try to mimic tube distortion, but that’s an alternative article.
Needless to say these are all very broad generalizations, and this is simply the maximum amount of due to circuit designs used in combination with tubes or transistors as the devices themselves, but exactly what are the distortions as well as other reasons tube amplifiers sound better?
Tube amplifiers have far more distortion than solid-state amplifiers, but most from it is second-order, which can be quite musical. That’s why it’s called “harmonic” distortion. Second-harmonic distortion is the same note, an octave above. Ditto for higher-order even harmonics; also, they are the identical note more octaves above. Even-order harmonic distortion is really so pleasant that in the 1970s the Aphex Aural Exciter was very popular in recording and broadcast specifically because it was designed to produce and add these harmonic distortions! You are able to still buy it today.
Not just is tube amplifier distortion harmonious, it increases as things get louder – exactly as they do in a musical performance. As instruments play louder, or as you hit a percussion instrument or piano key more strongly, they generate more harmonic content. As notes decay, the amount of harmonic content drops again.
Tube amplifiers mimic this. An excellent tube amplifier like the Woo Audio WA7 Fireflies increases its distortion directly with output level across 30 years of voltage, or a million-to-one power range. In contrast, here’s how a typical solid-state amplifier, in this case a Crown D-75, lowers its distortion with level, then suddenly clips in great amounts (the nearly vertical line on the right):
Be aware that the Woo graph is with regards to voltage output, and the Crown plot is in terms of power. Actually, the Woo plot covers an electric power range of over 6 million to 1, as the Crown plot only covers an electric power variety of 50,000 to a single. With this progressive, “dynamic” distortion, tubes add sharp attacks while retaining long, floating sustains for each musical note.
Just like our ears, musical instruments and almost everything else natural, tube amplifiers hold the least distortion at the cheapest levels. For this reason a tube amplifier can sound great played softly, while with transistor amplifiers people are usually being forced to transform it up to have it sound best. Honestly, I don’t bother using my dbx 3BX dynamic expander using a tube power amp, because it adds excessive dynamic impact.
Mingda Tube Amplifier sound their finest in the volumes where you truly wish to enjoy them. Just like digital systems, solid state amplifiers measure and sound their worst at lower levels, and also have their very best knhcnt at close to their maximum output levels where nobody ever actually plays them. For normal use with normal music at normal levels, many of us enjoy our music at about 1mW ~ 1W long term RMS, or about .01W ~ 10W peak. For many applications, a 30 WPC amplifier is about right.
What’s sad would be that the few consumer magazines that attempt to publish lab results usually only plot performance right down to 100mW, when in fact probably the most relevant power range in which we enjoy most amplifiers is from 1mW to 1W. What happens below 100mW is very important; that’s right where the majority of our music lives!
Sadly even if you pay $150,000 for a couple of overpriced frou-frou solid-state amplifiers, you’ll see its reviewer said many nice aspects of it, but he still said “the better I cranked them, the better they sounded” on page three. So for $150,000 they don’t sound best on the levels I wish to enjoy them? Adhere to the money; I don’t take ads from manufacturers.
Don’t let me hold you back if you want Xiangsheng Pre-amplifier, however, you don’t require it unless you want to crank it, use a big room or inefficient speakers, or enjoy very wide dynamic range classical music at concert-hall volume.