You can add a 2nd UCX, clock sync them by making a digital connection (ADAT/SPDIF) or by using WC and use them in parallel.
In the DAW you would load the ASIO driver and have by this acces to both interfaces.
You only need to take care in the driver settings to always set the same ASIO buffersize for both UCX so that DAW tracks are without offset.
EDIT: But the big disadvantage of such a solution is, that
- you can't route channel between the two TM FX instances (one per interface)
- so you would need to route a few things in the DAW.
Ok, you can make an ADAT connection additionally between the UCX and route a few channels between them, but this is operational PITA (pain in the ass). This is limited to 8ch at single and only 4ch at double speed.
You might be able to add MIDI ports in a different way, but if you want to add 1-2 ADA8200 then the UCX will always be a limitation to you because it has only 1 ADAT port.
Therefore my advice:
1. sell the UCX, you will still get a good price for it.
2. Then buy a new recording interface that fully satisfies your current and future I/O demands.
By getting one of the newer / flagship interfaces you get besides better preamps and analog I/O also additional features like e.g. Autoset and DURec.
You can use my Excel comparison sheet to compare technical data and features from this blog article:
https://www.tonstudio-forum.de/blog/ind … B-MADIfac/
Direct link to the Excel: https://www.tonstudio-forum.de/index.ph … -04b-xlsx/
I would consider getting either UFX II or even the UFX+. Then you not only get MADI but also two different possibilities to connect to the PC, either USB3 or Thunderbolt. Even USB2 is possible (as 30ch interface like the UFX II).
The UFX II / + gives you a wide range of different I/O types and analog ports. You can add ADA8200 as you want (it has two ADAT ports, so you can connect two of them). Later you can even think of adding MADI devices (64ch at single speed, 32ch at double speed). The UFX II/+ have 2x MIDI I/O and also two very good headphones outputs (even more powerful than those from the UCX).
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13