The big one and there's not much else to say : whoever has heard music through a pair of these Class A monoblocks knows what I'm talking about - the NR1 is basically a much improved TA-N7B.
Granted, finding and listening to Sony's ultra gear is difficult... for that brand is known to have not marketed most of its ultra units : whether its ESPRIT series, its monster LaserDisc players, its R1 and R10 series or the "1" follow-ups. A distribution often restricted to Japan's domestic market, no reviews, no worldwide drooling and, hence, Sony after all only makes great portable gadgets :-( However, the TA-NR1 is fairly easy to find because it sold rather well - Sony makes excellent High-End units.
The NR1 was withdrawn from the catalogs fairly quickly everywhere but remained available in Japan until circa 2000/2001, on special order, just like the fully MOS-FET and bigger TA-NR10.
At least 600 NR1 were made (that's 300 pairs), with a strange switch between production runs at the very end of it : throughout the run T-tagged by Sony's Ikari KK subsidiary, the last 50 (japanese) NR1s were tagged by Sony's Sony DP (and the export models as well)...
A real pair here, late in the production run.