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The NR1 was withdrawn from the catalogs fairly quickly everywhere but remained available in Japan until circa 2000/2001, on special order, just like the fully MOS-FET and bigger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 ; the highest s/n spotted was 200 608), 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)...
For the export markets (EU and, marginally US), about 100 pairs seem to have been made - so the total worldwide run should be around 800 pairs.
A real pair here, late in the production run.