This statement ticked off something in me when reading the article:
"The "Earths" are certainly very neutral, like their definition. But on the whole, they sound a bit rough: the sound, completely on fire and precise, is, however, a bit impoverished, [B]with the main notes very much in evidence, and lacking in harmonic tone[/B], a fact that one is able to notice, above all, in the acoustic pieces."
There can be 2 scenarios actually - A) OPA-Earth did not reproduce faithfully the sound and cut off the (nth-order, where n is a random number) harmonics, and B) The rest of the op-amps produced harmonics as their by-products which the listeners loved
But since it is widely known that chip op-amps produce more harmonics than transistor op-amps, B) is more likely to be possible.
People love harmonics, no doubt - evident in the widespread obsession with tubes, especially signal preamps as an unnecessary gain stage.
I'm not going to argue about hi-fi vs nice-fi, since I am guilty of using enhancements (I'd prefer calling compensation) and my system possibly has a big fat boost in the midrange
But calling the sound "completely on fire and precise" yet "impoverished" due to the lack of harmonics seems very contradictory, and the mention of acoustic pieces stretches it further - the violin has its own characteristic timbre, but when you record it, does the system see the timbre as itself - a complex waveform of sound pressure, or as the harmonics of the fundamental frequency?