So AT&T did studies in the 1960 when transistor amps were being developed as to what sorts of distortion the ear/brain system reacts to. IIRC they found that 2nd harmonic was mostly ignored by the brain, 3rd harmonic was identified as providing a fuller sound and higher harmonics especially odd higher order harmonics were annoying to the brain. @nd and 3rd
If a recording is produced with transparent electronics then playback with equipment works very well so the 122 sinad is great. However many recordings (mostly older) were produced using equipment with poor Slew Rates and copious amounts of high (with 741 op amps for example) order odd harmonics. These recordings when played back through new hardware with distortion with inaudible distortion can sound very harsh. So if some equipment in the playback chain has some 2nd and 3rd harmonic distortion to mask the nasties then they experience for the end user can be more pleasurable.
This is why Tube amps can be so popular. Many artist I and other enjoyed produced performances we love on horrible equipment. Some companies cater to these customers. The Atma-Sphere products has a reputation of lasting forever rather like MacIntosh products.
If a recording is produced with transparent electronics then playback with equipment works very well so the 122 sinad is great. However many recordings (mostly older) were produced using equipment with poor Slew Rates and copious amounts of high (with 741 op amps for example) order odd harmonics. These recordings when played back through new hardware with distortion with inaudible distortion can sound very harsh. So if some equipment in the playback chain has some 2nd and 3rd harmonic distortion to mask the nasties then they experience for the end user can be more pleasurable.
This is why Tube amps can be so popular. Many artist I and other enjoyed produced performances we love on horrible equipment. Some companies cater to these customers. The Atma-Sphere products has a reputation of lasting forever rather like MacIntosh products.