Ten year old digital source upgrade suggestions?

Hello
I use a Samsung SE 506 Blu-ray Disc drive to rip CD's via a generic USB cable to a 2011 Mac Mini which is wirelessly recognized by a Logitech Squeezebox Touch connected by an Analysis Plus Digital Optical cable to a Metrum Acoustics NOS DAC.
A ModWright power supply and tube stage modded Denon 3800 player is also connected to the NOS DAC with Cardas Golden Reference RCA.

I'm guessing the thrifty Samsung spinner and its included cable may have been a choke point?
We're very used to the Squeezebox, but?
Aside from power outages the Metrum has been on the whole time.
Is it just me or does the CD player sound a bit different than the ripped music?

For the sake of the everything matters context I consider the difference between an inexpensive moving magnet  phono cartridge and a multi $K moving coil cartridge or a change of speakers to be a substantial sonic change worthy of cost. At the same time I can easily hear cable changes with my system. 

I'd say I'm looking for the weakest link first and so on. 

M