EDIT: rephrased, some comments on FS clock, please re-read.
What do you have, an ADI-2 FS or an ADI-2 DAC FS? Could you kindly stay consistent in your product descriptions? Thanks.
Option A) if you connected an ADI-2 DAC FS as clock slave:
- D/A conversion happens in both cases (UFX, UFX III) on the ADI-2 DAC FS
- using it's internal FS clock
In this case, no difference whether you use UFX or UFX III
Option b) if you connected an ADI-2 FS as clock slave:
- D/A conversion happens in both cases (UFX, UFX III) on the ADI-2 FS
- but if I remember right clock is being used from clock master (either UFX or UFX III)
So, if I recall it right, the ADI-2 FS would use the clock from AES which is in the case of UFX III a FS clock.
Then it could be, that there is maybe a little difference in sound.
But I also remember that it has been mentioned on forum, that the introduction of FS clock alone with the ADI-2 Pro FS it delivered only better measurable but not audible better results.
The question is
- what device you have exactly and whether I remembered correctly that ADI-2 FS would use the clock from AES and
- whether you did proper blind testing to avoid any bias ..
I think there is a good chance that the difference is based on expectation / psychoacoustic effects, if tests have not been performed as blind tests with quick A/B tests possible.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13