"Do you know the HoloAudio Spring DAC?"

I believe that second harmonic distortion is sonic gold for audiophiles: It's very seductive, especially if you want a warm sound quality, three-dimensionality, and beautiful reproduction of ambience and depth. Based on the listening tests, there does not seem to be a sonic negative side if the proportions are done right. Yes, too much second harmonic and detail will be lost or the sound can become flubby, like some inferior tube preamp designs. That's why this listening test was so useful, as we can discover how much harmonic distortion is "just enough".