Part of Technics' last full-fledged audio-only series.

Launched just after Japan's 1990 economic crash, the "900" series and the related "5000" units didn't sell much. They had many qualities and very affordable prices but the market was going down and... Sony ruled anyway on the DAT market. Especially on the crucial 150k¥ part of it: the effective sales proportion of DTC-77ES vs SV-D900 should be around... 1 to 1000 :)
On the professional market, however, the Panasonic decks sold extremely well and the D900 uses the same RA-1001 mechanism as the revered SV-3700, SV-3800, SV-3900 or SV-4100... or the consumer SV-DA10 and SV-E10... or the Denon DTR-2000G or the Onkyos or the STUDER DAT recorders - same RAA-1001 everywhere !

The SV-D900 is a slightly upgraded SV-DA10 : Class AA analog circuits, some better componentry, OFC wires for the power transformer plus the BMC supplementary base and top and the (bulky) sideburns. The rest is exactly the same. At the center of the D900 was the MASH a/d and d/a chips: developped jointly by NTT (Nippon Telegraph and Telephone) and some part of the Matsushita empire, MASH converters allowed extreme linearity and zero cross distortion. Rather strangely for a top unit, multiple d/a chips were left out of the D900...

Some of the "900" units saw market-related versions under the "10" name (SL-PA10, SU-MA10 etc), some slightly different, some not... The SV-D900 was only released in Japan and somewhat "on order only".
The Technics brand was officially shut-down by Matsushita on december 28, 2005, after nearly 40 years of success - the market for high-end audio isn't down anymore, it has vanished forever.