There’s a Cambridge 851C on here and pretty sure seller is motivated to sale as its listed elsewhere. I have a 851C and an Oppo UDP 205 and the Cambridge is better. I use my 851C as a DAC as well for my Bluesound Vault 2 which it’s DAC is substantially better than the DAC in the Vault. The 851C is damn good.
As far as the Marantz CD6006, it’s not as refined as the Cambridge; it’s a good player but it is not up to the task (yes I’ve listened to one) and the 851C has digital in w/various inputs, single and balanced out and can be used as preamp out with your digital sources. The CD6006, besides sound quality, can’t compete.