I have this Yamaha CDX-593 player since 1999. It was the first player where I installed a clock (first generation from LC-Audio), back then.
It's collecting dust now, on a shelf.
Anyway, here's some (marketing) background on what Yamaha claims as a 'true' 20 bit system:
http://www.yamaha.com/yec/customer/tech ... probit.htm
After all these years, only a month ago I could get the service manual.
Yes, I payed for it.
Out of curiosity, I've always found this (modified) player very natural sounding, not 'digital' at all, and certainly one of the (if not really the) best sounding bitstream implementations I've heard, as cheap as the player is (was).
It also has that sort of dynamics like a good multibit dac.
Here's the relevant part of the schematic.
The Yamaha chip (YSZ914B-FES), in the middle of the pic, is between the decoder/digital filter (left) and the dac, an AD1854 (right)
What's goin' on here?