The CDX-1060 was the last in the line of super players starting in 1982 with the CD-1 and ending with the CDX-1060 in 1992 (it was sold until 1994). It had an MSRP of $800, even today they still catch a good price on e-pay only the CDX-1120, 2020 and special players like the CDX-5000 go for more.
Unfortunately Yamaha dropped there CD-P's from the American market in the early 90's so many Yamaha CD-P's were newer sold on the US market.
As mentioned earlier the 1030 uses the S-Bit DAC, where the 1050 and 1060 uses the S-Bit+ DAC. The main improvement lies in the DAC where the + stands for the added I-PDM part (Independent Impulse Density Modulation) Witch give the player better performance all over. The difference between the 1050 and 1060 is much smaller, I believe the 1060 is a tweaked 1050. The Yamaha engineers took the 1050 and said “how can we improve this without making a new design", the result is all kinds of small tweaks where the draw is the most eye catching. It resulted in a player that performs just a bit better than the 1050 (In my eyes it also looks better).
And then there is the lost child; the player that dropped from the sky, the CDX-993. It came out of nowhere, the super line of players ended in 1992 and then 6 years later in 1998 suddenly Yamaha made a new (and the last) super player. It started with the new Pro-Bit DAC in 1994 (YAC-514) developed for the CDX-880, then the engineers were allowed to make a player witch would take this DAC as high as it would go (and properly as high as Yamaha thinks 16 bit 44,1 kHz CD quality will go).
About the Pro-Bit I have to clarify, it is not instead of the S-Bit+. It is on top of the S-Bit+. The signal coming from the S-bit converter is run thru an intelligent selection where the Pro-Bit part applies one of 20.000 algorithms to up sample the signal to 20 bit dependent on the sound pattern. PRO-Bit stands for Precise Reproduction of Original Bit.
An interesting thing about the CDX-993 is the name, it IS a super player and normally it would be named CDX-xxxx. But the weight of the player drops just below 10kg (9,6 kg), so it was not given the name CDX-1093. If the reason is internal politics (I think the player was designed by Yamahas English design team) or just a simple rule of the 10kg I do not know, but it is a small mystery.