Dazzdax, you may be on to something, because in the case of the particular tube preamp we tested, it was actually the feet that resulted in the most deviant performance that I thought sounded the best (or most natural)... So it may be the euphonic distortions that the ear prefers rather than the most technically perfect reproduction...? I find a direct correlation with these results and audiophiles' general love of tube sound, since tubes are generally rich in even order harmonic distortions.
Recently, my quest has taken me to search for amps that measure very well, and actually come across that way from a subjective sonic standpoint. My recent fascination with the NuForce amps is case in point. These diminutive digital amps are VERY MUSICAL -- and their distortion levels are VERY low -- the opposite of how it usually works in the world of audiophile componentry. It's all very interesting.