Thanks for your replies.
@RME Support: Okay, I'll put my question this way: Will the ADI-2 FS fullfill the idea of faithful reproduction of the original the same way like the ADI-2 Pro?
@ramses: Sounds like a decent plan. I will consider it. But if @vinark is right and it makes all no difference, I will stick with my Fireface until its broken;) I just thought there is some special quality of the reproduction of the original by the ADI-2 interfaces.
Vinark argues on the basis that converter differences are very small.
Personally, I consider A/D conversion to be less critical than D/A conversion. Microphones, for example, have significantly poorer SNR values compared to todays A/D converter. And as far as D/A is concerned, with a multi-tack recording, the spatiality is only created during the mixing (except when perhaps doing stereo recording).
Various components are responsible for ensuring that spatiality can be optimally reproduced: room, loudspeakers, amplifiers, D/A converters.
Kai once posted why he prefers the slow filter on the ADI-2 Pro.
https://forum.rme-audio.de/viewtopic.ph … 68#p177168
https://forum.rme-audio.de/viewtopic.ph … 41#p186341
You you also can assume that KaiS has also a very good room, excellent active monitors etc.
These filters all have pros/cons among them conversion speed, etc. But to have selectable filters you need a product where this can be selected. All recording interfaces have usually AD/DA converter where converter latency is low and linear frequency response is well in the hearing range.
But when choosing such product with selectable AD/DA filter then you need to get either ADI-2 DAC or Pro and then also everything else has to be right in order to be able to perceive it at all, quite apart from the fact that we all hear differently. And by that I mean both listening habits and hearing ability (!).
If you really want something very good, including the really great product features, then get an ADI-2 Pro right away. It's excellend for your monitoring. But you could also postpone that !
I personally would sell the FF400 asap as long as there is a market for it. If you continue to operate it the likeliness is quite high that the value is getting lower and once it's completely dead, then you do not get any money out of it anymore. Makes no sense IMHO.
Then it's really better to get a UCX, which after 15 years delivers significantly better quality and features in every respect.
There are people who, after connecting their €200 monitors, want to hear a quality improvement when using the ADI-2 Pro, but such spontaneous statements, which certainly did not result from a blind test, should always be treated with caution. In my opinion, you should better have a good room and active monitors with excellent speakers, so that the sound quality can be better transported to you as listener. But you didn't tell anything about your surrounding conditions, not even what you record and how.
Besides this you would benefit from a better / richer feature set of both units, UCX II and ADI-2 Pro.
My recommendation again: buy the UCX II, then sell the FF400, then save money and add the ADI-2 Pro FS and integrate it into the setup. If you should have the feeling that the ADI-2 Pro FS doesn't bring you any further benefit, then send it back and enjoy the UCX II alone.
UFX+, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1650v4, Win10Pro22H2, Cub12Pro