As I suspected: marketing BS! In the world of speaker amps, single-ended (such as SET amps) are revered (by some). The idea is that the less components that are producing your sound signal, the more pure it is likely to be. But it seems that the headphone industry has turned this around and done the opposite, by using a 'nice' sounding word to sell their amps, maybe because the word 'balanced' just sounds right, whereas 'differential' is....forgettable. I know that they're much higher impedance, but I'm sure that SE is generally more appropriate for driving headphones than it is for loudspeakers. My main frustration is the cabling: you don't have different connectors for SE and balanced....sorry....differential amplifiers for speakers, but for headphones....it gets complicated!