older CD transport vs newer ones.

Funny you guys mention PS Audio PWT. It was the very next transport I tried after ML #37, so disappointed! Even after modding never came close to 37, much darker sounding, less involving, the 37 was such a special transport, on top of one of the best transport mechanism (Phillips Pro), the had proprietary mounting and servo. After selling PWT, gave up transports, migrated to streaming,  cd rips on NAS sound fabulous.
I no longer trust cd transports, I've used couple cheaper ones in bedroom system, both Emotiva and Sony have died. Cheap mechanisms used in these can be purchased for $20 or less on ebay. I'd check to see what mechanism used before I'd lay my money down for any modern transport, only the bespoke would be of any interest, something like Esoteric.

Jays Transport 

I disagree with slot loaders being rubbish.

Sorry but they are made for cars, 3in1’s, portables and computers with cheap Chinese lasers/motor assemblies etc
And they can put horizontal scratches right across the cd if there’s the smallest dust particles on the slot brushes.

Cheers George

Since you already have a dCS, great products, and you are very happy with the brand I would look for a matching dCS Transport, one that has a a VRDS, or Stream Unlimited transport mechanism. The overall performance will be seamlessly next level.

One of the greatest transports ever built was by TEAC - the VRDS. Which most always uses a Sony laser. For many years it was featured in most all Wadia digital components. TEAC  came up with a High End division called ESOTERIC which used the transport mechanism exclusively leaving other companies like Wadia out in the cold, for a while.

The VRDS NEO is regarded as the Best transport ever built. The VMK3 version is featured in dCS Vivaldi units, as well as several ESOTERIC units. Wadia was said on planning to produce their All in One 981 units with the VRDS NEO before their demise, only 6 prototypes were ever built, only 2 had a VRDS mechanism, none of those were NEOs.

It is my understanding that Philips has recently developed a similar type Transport which is said to rival the TEAC version at a fraction of the cost. You could also look for an ESOTERIC unit to integrate into your system. 

What ever you decide good luck. 

I second sns with the Mark Levinson #37 drive and Philips CD-Pro transport - I used this drive built in Madrigal Proceed PMDT in combinstion with Reimyo DAP 999 EX Ltd. for many years and it sounded great, nothing came close.
When the laser finally died I tested a lot of different CD- and DVD- drives as transports only (Denon, Primare, Micromega, Electrocompaniet, PS Audio PWT, TEAC) - nothing showed the same sonic quality.
Finally ended up with Audio Research Ref. CD9 SE carrying again the Philips CD Pro-Transport, which is said to be one of the very best drives ever built.
The Project CD-Box RS-2T sounds interesting as it carries the Stream Unlimited (ex-Philips Engineers) CD-Pro 8 transport - this company also supplied the laser drive for the Wadia S7i which is not a bad reputation at all.
Furthermore I second charles1dad that the better the transport the better the sound! 
Probably you can find an AR Ref. CD8 used with Philips CD Pro Laser mech. and use it as a transport only with your Rossini DAC (I clearly preferred even the AR Ref.8 to the PS Audio PWT, the Ref.9 is even better than Ref.8 IMO)