Thanks for pointing me to dCS. I read the Vivaldi review in Stereophile which includes this paragraph addressing my question.
Which is not to say, “Come back, Compact Disc—all is forgiven!” With hi-rez recordings at my fingertips, including some for which I also had the CDs, two things were clear: 1) While the best-engineered and -produced CDs can sound pretty good, CD sound pales next to SACD or hi-rez PCM; and 2) Those who trumpet CD’s transparency and claim that higher resolution is inaudible are being guided by mathematical “proof”—not their ears, which for some reason they fail to trust.
So, even with a $70k+ DAC stack, the CD recording is limiting the performance. This is what I expected, since my GDAC sounds wonderful for 24/192 and my vinyl. I’ll have to try the new DS DAC when it comes out to see how it compares.
Thanks all