A certain Keith G, of uk.rec.audio "fame", writes :

Nooooo.....

I'm talking about disks where there are both CD and SACD versions of the
same music.

It depends whether or not they are taken from the same master.

If you take the same master and put it on SACD and CD, they will both be
identical. Any differences will be down to differences in the player,
not the recording.

--

"Jokes mentioning ducks were considered particularly funny." - cnn.com