As strongly as I believe that the listening experience is the most reliable method of judging the quality of audio equipment, I've been biased against single-ended tube amplifiers because of their quirky measured performances. Without having heard single-ended under good conditions—much less living with an SE amplifier—I had concluded that many listeners must like them because they're euphonically colored by large amounts of low-order distortion and impedance interactions with the loudspeakers. SE amplifiers seem to be a departure from the goal of making the electronics transparent. Moreover, the range of loudspeakers suitable for SE amplifiers is so restrictive that I wondered why anyone would bother with these underpowered distortion-generators. I had fallen into a trap that I've repeatedly railed against: drawing conclusions without firsthand listening experience (footnote 1).
The $395 NAIT, rated at 20Wpc, is a good-sounding little amp. It's very open and spacious-sounding, but, like the $250 Rotel RA-820BX, sometimes sounds a little hard in the upper registers.