One of the ultimate LP record players launched shortly before digital disc would definitely change the landscape.
It isn't "the" absolute LP replay machine (absolute-ness isn't of this world) but measured performance is simply stunning and, unlike what its looks may indicate, the DP-100 was targeted at the consumer market.
The center of the DP-100 : a 15 x 14cm stator, leaf spring + oil decoupled 6,850kg two-piece platter and a 13 x 13cm rotor holding 21 coils. The shaft is 1,4cm in diameter.
At the center of this is the AU-169 Unit motor, which was first presented by Denon at the 1979 Japan Audio Fair and developed for cutting lathes - hence the presence of that all too often used icon on each of the many ads Denon published in Japan.
Albeit enormous, the version inside the DP-100 is however somewhat smaller than the AU-169 - especially its power-supply !
The top frame is made of a c. 1...4cm thick single diecast aluminium piece, rectified and finished in hammered style with a varnish added. Although not Denon's forte, ever, this one color + finish team is absolutely beautiful.
The four feet mix springs, an articulated piston and oil to isolate a total mass of 48kg.
The speed locking system is equivalent to that of any 1970s Denon or Sony turntable : a 1000 magnetic pulses are printed on the platter's rim, read by a magnetic head and fed into a Quartz PLL loop.
The small front lid hides the secondary controls : speed selection, pitch control, anti-skating & lifter speed (for the DP-100M) plus two controls which only the stock tonearm allows - Cut off frequency between 3Hz and 13Hz and Q Damping to tame the inherent 8Hz resonance of the tonearm.
The tonearm installed on the DP-100 is of the Dynamic Servo Tracer kind : filled with coils, magnets and sensors to effectively follow the groove in an "active" manner. Like a Sony Biotracer but simpler.
Wands are interchangeable : medium weight in "S" shape or low-weight in straight shape ; the straight wand is made of "a special light alloy which has been heat-treated, like a cartridge cantilever".
The DP-100 is the barenaked arm-less version but, like the DP-100M, it has an interchangeable armboard to fit any other tonearm of almost any size : the original one measures 28,2cm.
An optional DK-1000 wood+leather enclosure pushed the bill to 1,100,000¥ but only about one on ten DP-100 was fitted with it.
The total production run for the DP-100 and DP-100M is anybody's guess but should be around 250 pieces.
The highest serial number spotted in Japan (on a 100) bears an 11 8 118 ("11" means Denon factory, "5" is product run (or month ?) and "118" is the actual s/n) ; another (on a 100M) has an #11 3 088. The highest DK-1000 serial spotted is #67 so either more DP-100/m were made or more DK-1000...
From these and others we can guess a production running over several months, each run quite possibly launched when enough orders had been received.
Denon in Japan doesn't remember anyhting but Denon in Germany recently unearthed a forgotten demo sample in its warehouse (!) and it bears a n°3 serial number (probably a pre-prod. sample).
The last prototype, shown at the 1980 Japan Audio Fair, was at the same time completely different and somewhat equivalent : more obvious consumer design (less "streamlined") and smaller in width, depth and height but the link between the two is evident (unlike the original L-07D 1978 proto' and the final product).
It should be noted that around 1991 Denon planned and built a fully finished and functional studio turntable prototype named DP-X to try and come back into high-end LP replay.
This DP-X was however not produced : ten years was too long an absence for a come-back.
A real 100M here, with serial #11 2 003. ("11" is the regular Denon prefix, for all that was built in-house ; "003" is the actual s/n).