It is an interesting deck - the prototype was even cleverer! I do have one though it has stopped working again! Tim did have a look at it a while ago but it misbehaved very rapidly! We think it is probably based on an Aiwa - Tim did find the machine he thinks it is based on but this is so obscure he has never found one in the flesh! It showed that B&O were covering their options by developing both a Philips based machine (the CDX) which used the 14 bit 4x oversampling route and the Japanese 16 bit 2x oversampling.
I actually bought a CD50 new when I had my 5000 system but sent it back because it was so noisy! I used a Philips CD player for a year or so before I replaced the system with a Beocenter 9500. My present CD50 is slightly quieter (well obviously a lot quieter at present! 😂 ) but a lot noisier than the CD5500.
My B&O Icons: