Which functions do you mean in particular? Room EQ?
The best would be to upgrade to an UFX II and to sell the UFX to re-finance. You will still get a good price for the UFX.

I see certain disadvantages in operation if you would connect the UFX to the UFX II, which has only 1 ADAT port.
So you could transfer only 8 (of the 30) channels at single speed and only 4 channels at double speed.
Also operation would be more combersome as all needs to be routed through this one ADAT port.

You could as an alternative connect UFX II and UFX in parallel and clock synch both devices, but this has other operational disadvantages as then you would always have to route your monitoring from UCX II through USB to UFX. This is too cumbersome for my taste, I would not recommend this to you.
Also for the latency compensation it would not be ideal, as UFX and UCX II have different converters with a different latency. then the latency compensation will not be correct for one of the two interfaces.

The best solution would be to directly upgrade to an UFX II or even UFX III.
Then you have the same plugs and you can most likely even load your workspace from the UFX to the UFX II, as the number and type of ports is equal.

EDIT: BTW. With the UFX II you will also get the same converter as the reference converter ADI-2 Pro FS. You might have read in the forum that the UFX II has now the same analogue board as the UFX III.

There are quite a lot of interesting and significant differences between:

A) UFX and UFX+/II
    https://www.tonstudio-forum.de/blog/Entry/68-RME-UFX/

B) UFX+/II and UFX III/II (updated UFXII with analog section from UFX III)
    https://www.tonstudio-forum.de/blog/ent … iii-en-de/

Summary of differences

A) UFX and UFX+/II

• revised version of analogue circuits and DSP

• improved SNR and THD values

• DURec: internal RTC (Real-Time Clock), allows timestamps in DURec recordings

• DURec: increased reliability when using slower or multi-partitioned USB thumb devices

• DURec: supports multiple FAT32 partitions, last active automatically reactivated after power-cycle

• Microphone inputs with + 18dBU max, no PAD

• Microphone inputs with 75 dB Gain Range, 10dB more compared to UCX/UFX

• Headphone outputs with only 2 ohm impedance, with +19 dBu max output level

• New Remote Control "ARC USB" (details below) for regular and stand-alone operation

• ARC USB pluggable either to the UFX+ or alternatively to the computer (TotalMix FX does the interfacing)

• Word clock BNC switchable to MADI coaxial

• Rotary encoders on the right of the display now individually adjust the volume of Phones 9/10 and 11/12.

• Fully stand-alone. There are additional settings compared to the UFX.

• New MADIface driver supports smaller ASIO buffer sizes down to 32 samples (UFX 48 samples)

• Only UFX+: USB3, Thunderbolt connection to Windows / Mac, supports "hot-plugging" under Windows

• Only UFX+: Additional 64 channels by MADI with the options: auto, optical, coaxial and split

• Only UFX+: total channel count 188 channels (94 IN, 94 OUT): 24 analogue, 32 ADAT, 4 AES, 128 MADI

• Only UFX+: MADI split mode allows 32 channels each via MADI optical / coaxial

• Only UFX+: MADI I/O via TotalMix still available on USB2 for local routing, but no SW playbacks, audio from PC)

• Only UFX+: DURec: up to 76 channels can be recorded simultaneously - optionally 12 analogue and 64 MADI inputs

B) UFX+/II and UFX III/II (updated UFX II with analogue section from UFX III)

• A new analogue section with improved SNR values and 6 dB better THD+N.

• High-quality converters from AKM (AK5574 as AD converter and AK4490 as DA converter), which are already familiar from the ADI-2 Pro FS.

• Fast converters with only 5 samples of AD latency and 6 samples of DA converter latency.

• All analogue outputs are now "DC coupled" and suitable for controlling synthesizers.

• USB3 CC mode allows the utilization of all 94 I/O ports, regardless of whether for Linux, Mac, or iPadOS.

• Track names for DURec, where the user-defined channel names in TotalMix are adopted as track names in DURec recordings. During the subsequent conversion of the DURec multichannel files (using RME's Wav-File-Batch-Processor 1.31), individual channel files receive the track name as the file name.

• Remap Keys enable the assignment of 33 different functions to the four direct selection buttons on the display.

• Lock Keys allow deactivating only the four front buttons or even the three encoders (first introduced with the UCX II).

• FS (Femto second) clock.

• The digital section has also been revised, and the UFX III now features 3 separate AES/SPDIF receivers and transmitters, enabling both ADAT ports to be switched to optical SPDIF.
  

Hi Alex.

It is no problem to combine any recording interface with an ADI-2 Pro FS R BE or even ADI-2/4 Pro SE reference converter.
Model differences and nice features (except ADI-2/4 Pro SE) see this blog article: https://www.tonstudio-forum.de/blog/Ent … ses-EN-DE/

You can connect the ADI-2 Pro or ADI-2/4 Pro SE via AES or ADAT, there is no quality degradation.
See my blog article about the integration into your setup:
https://www.tonstudio-forum.de/blog/Ent … our-Setup/

Also, AES provides galvanic isolation and would allow for even longer cable runs in the studio.
ADAT has IMHO two advantages:
- you do not need the breakout cable (one cable tree less)
- small diameter optical TOSLINK cable, can be up to approx 16 m long (although specs tell 10 m)
But if you needed the two ADAT ports for other stuff, then use AES.

I would think twice and decide to go straight with a combination of UFX III and ADI-2 Pro FS R BE.
Reason: you have more possibilities / options to expand in terms of additional hardware through MADI.
Two ADAT ports can quickly be too few especially if you want to have the freedom to be able to record in double speed.
Look at the 12Mic at double speed, for 12 analog inputs you need already 3 ADAT ports for recording at double speed.

The UFX II / UFX III are in a price range where I would say, this is most likely your last / final recording interface, as it gives you everything you might need. Therefore it makes sense, to choose the UFX III with MADI to be future proof for greater sustainability after purchase.

Another reason is, that you can make use of not used MADI ports for creating submixes and recording them via loopback recording. If your ADAT and AES ports are already in use, then this is not possible.

My proposal for you is such a setup that I have. You do not need all of these devices, I only wanted to give you an idea.
Basically, I talk about: UFX III, ARC USB, ADI-2 Pro FS R BE, the rest is an option.
Also nice in such a setup is ADI-2 Pro FS R BE as SRC (sample rate converter for DAT or some guitar emulations)

PC----ARC USB
|                                                        TV+
| USB3                                     BluRay+  \
|                                                           \   \
UFX III+---ADAT1 OUT-----------TOSLINK Switcher-----Optional: ADI-2 Pro FS R BE #2----->e.g. HiFi as Main Out B
|         |        \                                                                       central D/A conversion for different sources in front of HiFi
|         |         \
|         |          +---ADAT2 OUT--------->ADAT IN---ADI-2 Pro FS R BE+---AN1/2 OUT---->Monitors (Main Out)
|         |                                                                                  +---AN3/4 OUT---->Phones
|         Optional: AD/DA Converter                                         +---AN IN<---Analogue Device
|         |                                                                                  +SPDIF<----SRC----DAT or alike
|         Optional: Mic Preamp
|         |
+MADI+
  OM4

My setup as an example:
Blog article about UFX III with some photos, the link mentioned above already:
https://www.tonstudio-forum.de/blog/ent … iii-en-de/
Setup Diagram: https://www.tonstudio-forum.de/attachme … -v002-jpg/

Very future proof...

Alternative: get UFX II sell UFX.