Originally Posted by Walbaum
Some of the models are: CD-36, CD-46, CD-52MkII, CD-57, CD-57MkII, CD-67MkII etc.
Generally with Marantz the higher numbers are better (unless it's below 20 in which case it's really high end stuff)
The 52MKII is good, that's an early bitstream machine from around 1992-4 when they were still very well made. The 57/57Mk2 or 67MkII are mid- late 90s and would be the ones I'd go for from that list.
The 36 and 46 were more budget machines as far as I remember.
Generally all but the really high end machines will be very cheap 2nd hand. The 1980s ones are also more expensive because of collectors value. The real affordable classic 1990s machine was the CD63MkII / Ken Ishiwata Signature. Also look out for earlier machines called "SE" as these were limited editions prior to KIS.