Blitzula,
The CD3.5 uses a 18 bit DAC with Phillips VAM1201 transport.
Amasingly still a good player but it can sound really rough around the edges compared to the newer Naim players. I do like how this player carries on the tune. It drives the music from the bottoms up rather than the head first. No sticking out trebles and has a better note shaping than its predecessor.
Upside of the CD3.5 over the CD5i is you have an option to add an external PSU later whereas CD5i, you can not.
CDS2/XPS:
This is a Naim's former flagship player with the old PSU. ( current model is XPS2 with slightly different voicing )
Most natural sounding out of all Olive range. Better frequency extension, resolution and warmer tonal balance yet it has the best timing out of the old range and can still compete well with the new players.
As you expect, it is better rounded than the CD5i and it just offers so much more in frequency extensions and whole lot less mechanical. ( even compared to the new CDX2 )
CDX/XPS
The seller is offering it with the older PSU. I even liked this player *bare*.
What added power supply units offer is a better handling on the bass notes and it opens up the entire frequency range. ( wider stage and effortlessness )
The music sounds more convicing.
The sonic gain from the CD3.5 and even a bare CDX ( meaning not using an external power supply ) is quite large.
Don't get hang up on the word 'smoother'.
It's relative to the CD5i. It's smoother compared to the CD5i or CD3.5.
But it's still a Naim player. IF the speed, fun and dynamcis are your thing, it kicks arse over any of the familiar CD players mentioned on this board (excluding Krell players
)
At any rate, if you are thinking buying used off the net, I'd suggest get the serial numbers from the seller and check it against the service record at NANA. ( Naim Audio North America)
And check it against how old the unit is:
Naim Product History
Naim Serial Numbers
Generally, later the serial numbers, better. As Naim often revises the inside cct. without letting the public know. Also, as a rule of thumb, for digital gear, newer is better because of less wear and glitches on the transport themselves.
AFAIK, Naim still stocks the transports used in aforementioned players, but I would also check with NANA. I was told that they are out of CD3 and older transports.
Also, ask the seller if the players have the PIC upgrade. This is important since PIC chip will able to read the copy protected discs. ( Still all Naim players can't read a CDRW )
Info on the PIC upgrade
Finally, all those older players do not have RCA outs. ( infamous DIN thing ) so you need a DIN/RCA lead if you are using non-Naim preamp. No biggy as number of after market cable producers should be able to fit source end DIN. Just make sure pin configutaion is correct. ( consult NANA )
Manuals
Is it pain in the arse?
You bet ya. But you really ought to do a home-work before you purchase one of the older Naim players off the Net.
This is one of the reason, I prefer to deal with an authorised dealer.
Good luck.