Tube amplifiers sound better due to the euphonic distortions they enhance the music, along with plenty of other reasons. I’ll cover below. These are generally subtle effects most audible to musicians and very dedicated music lovers; casual listeners (those who “listen” with their eyes open while doing something different) usually won’t notice, but sometimes the main difference is so obvious that people’s wives will comment that “wow, that sounds significantly better” when individuals use tubes at home.
Tube amplifiers measure poorly inside the lab specifically due to these added distortions, however, these distortions tend to be part of what get them to sound better. To this day having an all-digital infrastructure from recording studio to SMSL DAC for many years and decades and decades used 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 since they have the music we create sound better: smoother, warmer and cleaner.
Ditto for guitar amplifiers used in creating music. The methods that tubes distort when pushed to the edge are much more musical than the artificial sounds that come from transistor amplifiers when overdriven. Some transistor guitar amplifiers make an effort to mimic tube distortion, but that’s a different article.
Obviously these are generally all very broad generalizations, and this is simply as much as a result of circuit designs used with tubes or transistors since the devices themselves, but do you know the distortions and other reasons tube amplifiers sound better?
Tube amplifiers have a lot more distortion than solid-state amplifiers, but most of it is second-order, which is 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; they are also exactly the same note more octaves above. Even-order harmonic distortion can be so pleasant that during the 1970s the Aphex Aural Exciter was extremely popular in recording and broadcast specifically as it was made to generate and add these harmonic distortions! You are able to still purchase it today.
Not merely is tube amplifier distortion harmonious, it improves as things get louder – exactly as they do in a musical performance. As instruments play louder, or when you hit a percussion instrument or piano key more strongly, they generate more harmonic content. As notes decay, the percentage of harmonic content drops again.
Tube amplifiers mimic this. A good tube amplifier such as the Woo Audio WA7 Fireflies increases its distortion directly with output level across 30 years of voltage, or even a million-to-one power range. In contrast, here’s just how a typical solid-state amplifier, in cases like this a Crown D-75, lowers its distortion with level, and after that suddenly clips like crazy (the nearly vertical line on the right):
Note that the Woo graph is in terms of voltage output, and the Crown plot is when it comes to power. In fact, the Woo plot covers a power selection of over 6 million to a single, as the Crown plot only covers a power selection of 50,000 to 1. With this particular progressive, “dynamic” distortion, tubes add sharp attacks while retaining long, floating sustains for each musical note.
The same as our ears, musical instruments and pretty much everything else natural, tube amplifiers possess the least distortion at the smallest levels. This is the reason a tube amplifier can sound great played softly, while with transistor amplifiers individuals are usually being forced to change it up to get it sound best. Honestly, I don’t bother using my dbx 3BX dynamic expander with a tube power amp, as it adds a lot of dynamic impact.
Meixing MingDa Valve Amplifier sound their finest in the volumes in which you really desire to enjoy them. The same as digital systems, solid state amplifiers measure and sound their worst at lower levels, and possess their best knhcnt at near their maximum output levels where no person 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 the majority of applications, a 30 WPC amplifier is approximately right.
What’s sad is that the few consumer magazines that make an effort to publish lab results usually only plot performance right down to 100mW, if in fact probably the most relevant power range where we enjoy most amplifiers comes from 1mW to 1W. What will happen below 100mW is extremely important; that’s right where almost all of our music lives!
Sadly even though you pay $150,000 for a pair of overpriced frou-frou solid-state amplifiers, you’ll see its reviewer said many nice reasons for it, but he still said “the greater I cranked them, the higher they sounded” on page three. So for $150,000 they don’t sound best in the levels I would like to enjoy them? Stick to the money; I don’t take ads from manufacturers.
Don’t let me stop you if you want Xiangsheng Pre-amplifier, but you don’t want it unless you like to crank it, possess a big room or inefficient speakers, or enjoy very wide dynamic range classical music at concert-hall volume.