Thanks to Sony's industrial clout and good marketing perspective, the 101 is without a doubt the most remembered 1st generation CD player.
It should be kept in mind, however, that the hardware side of the format (which is what made it really new and different) came from Philips ; it is mainly the PCM coding and error correction schemes that Sony perfected for this Philips format.
Build-quality is equivalent to that of all 1st gen' players : nowadays unbelievable - which doesn't mean reliable :)
D/A conversion is done by Sony's own chips : CX-7933, CX-7934, CX-7935 and the CX-20017 for the digital to analogue conversion itself.
The back of the CDP-101 holds a very substantial transformer and heatsink, a pair of output plugs, "auto-pause" and "anti-shock" switches.
Some models sported a "sync out" minijack output as well which was planned to launch the record mode on cassette recorders with the help of the ubiquitous RM-65.
All versions had the mysterious "accessory" connector, planned for graphics to be output - CD after all only was the side result of Laserdisc reasearch. That terminal, however, was never used by anyone.
If Sony's bigger players were all metal, the CDP-101, showing what the future held, has its enclosure made of hardened plastic with a glossy and slightly metallized finish - very good-looking and not feeling "plasticky" at all.
According to legend, the name "101" was chosen with the formats' coding scheme (0s and 1s) and because "101" is the PCM equivalent of "5" - and 5 is a lucky number in Japan.
Given the astounding amount of CD players Sony sold throughout the 1980s and early 1990s - more than any other manufacturer - the lucky number's charm worked very well.
Sound-wise, the 101 is part of the best 1st gen' players I have heard : deep, well-defined bass, lush highs and a midband which isn't all that bad. Where it fails, like all 1st gen' players, is on the fortes : when there suddenly is a big surge in dynamics.
One is then reminded this is a 1st gen' player indeed : squashed and blurry soundstage, grainy and overemphasized highs.
Feel-of-use-wise, it is up to any early/mid 1990s ES player - in a different way, of course.
The compactness adds to the impression of solidity for if the case and front are of hardened plastic, all of the rest, transport pads included, is metal and metal only.
Best of all : said pads are relay-driven so there is no mechanical click but only a click from the relays inside only. That certainly ads to the magic for the CDP-101 really gives the feeling it follows the commands non-mechanically, almost etherally.
The blend of materials, textures, finishes and color hues is part of Sony's all-time best.
However, sadly, in true Sony tradition, especially in the 1980s, none, absolutely none of the official images show any of it.