There is a difference in sound between the S910 and T2, especially when when played through some good speakers. I happen to have a friend's S910 besides my T2, played through Mackie SRM450's (same settings, cables, CMP OFF and EQ flat, Effects Off, Studio Drum Kit), and the T2 sounds much cleaner and discrete. Also, there is less noise coming from the T2 outputs.
Yes, there is a difference...and, I think the S910 sounds more like the Tyros2 than the Tyros3.
That said
...the S910 has a
slightly (very slightly) thinner sound,
but not on all patches...some are equal, including the SA Sax and SA Concert Guitar. Some are are different, like the Live Grand Piano and the synth sounds.
As Diki said in an earlier post, sometimes a big
fat sound is not what is wanted...perhaps that's why I like the S910 so much...and, also why I liked the Tyros2 over the Tyros3, the former being sweeter and less robust,
but in a good way.
I didn't find the S910's outputs noisier than the Tyros2, but it could have been the way I set them up.
Ian