Pioneer's first CD player was entirely home-made - laser-block and d/a conversion excluded.
As produced, the P-D1 surely did not comply to Pioneer's earlier attempt to include 4-channel surround sound in the upcoming DAD format, as implemented in the Model 1516 prototype.
The feature still was a "possible option" as late as april 1981 and Philips wasn't entirely against it either...
The P-D1, in its final shape, as presented at the 1982 Japan Audio Fair, was ready (and shown) at the october 1981 Fair, but marketed only a year later, during the official japanese launch of CD in october 1982. The last (brief) pre-production sample was btw named PL-1000.
At 198,000¥ in 1983, the P-D1 was near the top of th 1st gen' crop but seemingly didn't sell much and is nowadays an x-rare rarity nowadays.
My own P-D1 unfortunately wanders more than it actually plays music so I cannot comment on its sound qualities... But it is part of the units I will never ever let go.
The P-D1 is design-wise one of the true masterpieces with not only the two-piece structured transparent hub but a work on textures, hairline anodization and edge details (generally not Pioneer's forte) which is near perfection.