I should listen to my cd collection more - but they are mostly representative of the older sampling methods so somewhat obsolete/incomplete.
This is the area where you can benefit most from an upgrade. Modern digital technology has improved the old Redbook format by leaps and bounds. A high quality DAC mated with a transport, such as Cambridge or PS Audio, now reveals detail in CD's never before possible. There are so many threads now stating how members are enjoying the sonics coming from those silver disks.
If you have a large CD collection, then maybe you should head in this direction.
Multibit DACs are able to process 16/44 Redbook in its native form and the result is a more natural, realistic sound from digital.
DSD capabile DACs can process SACD and hires files resulting in excellent SQ.