Ok, but surely RME knows the pin assignment since they make both products. Why haven't they done a for purpose cable already?

If you want uncluttered and simple, why not optical or USB? There is no difference! And why a PCIe card?

Years ago, when the ADI-2 DAC FS was the 1st unit released with FS clock, there was a discussion in this forum, whether FS clock would lead to audible better sound. The final agreement was, that SNR and jitter suppression is measurable better, but not audible.

Getting a PCIe card with TotalMix FX could give you some flexibility in terms of routing, but is not really required if you do not need it.

But if you get such a card, for whatever reason, then I would use a TOSLINK connection, as vinark wrote.

Simple and straightforward. You can plug them directly between the devices, you can perform clock synchronization over any digital connection. There is no better or worse quality, it's simply a digital connection which also provides galvanic isolation like (as good as every) AES implementation does.

Otherwise, use USB. Keep it simple!
Hint: if somebody - maybe from another forum — would tell you that an "audiophile USB cable" is needed .. this is pure nonsense, save the money. This is also digital transmission of audio data over USB. I can recommend you Lindy cables, which have an excellent price / quality ratio. Up to 5 m is possible using USB2. Do not spend more than €15-25.

Thank you both for the information!

Saw the information about the clock in the HDSPe AIO so I will probably go with that and toslink instead then, to avoid the breakout cable and seems I can explore many other options with that as well.

[ EDIT: in clarification with RME ]

I forgot to mention one thing.

The design of the ADI-2 DAC / Pro FS device series is special.

Even if the device is configured as a clock slave, the final D/A conversion is done with its internal non-FS clock.

This means that operating the ADI-2 Pro as slave to a master with FS clock will bring you no benefit.
If you don't need the HDSPe AIO Pro for other purposes (TM FX, routing), better save the money.

I'm just clarifying something with RME about D/A conversion in post #11.

Regarding your PC. That the PC doesn't boot and needs an USB install media to boot is strange.

Questioning myself what would be different or how could a RME PCIe based recording interface "cure" this?
If the PC is so hung up that all input devices not work, is your expectation, that at least music continues to run
through HDSPe AIO PCIe card and further to  ADI-2 Pro AE via AES or ADAT?

If the PC is not reacting to mouse or keyboard activity, the 1st action I would do is to reboot and fix it.
So I am really questioning what benefits you would have with a PCIe card.

Maybe a better solution is, to buy a dedicated PCIe USB3 card to connect only the ADI-2 Pro AE,
then the ADI-2 Pro AE is fully separated from the other USB infrastructure.
A good card with a good USB3 chipset (fully compatible to USB2) that is even known to work very well
with UFX III would only cost around €50 and is maybe worth a try.
https://www.sonnettech.com/product/alle … 4port.html

Windows 10 and 11 have drivers for this card included. The driver work with the more efficient MSI (message signalling) interrupt model.

To avoid misunderstandings about your setup, could you kindly post a diagram of your setup with the two PCs the switcher and how ADI-2 Pro AE and other external devices are connected to each other?
A little ASCI drawing which is quickly done in the editor here, like this for example: https://forum.rme-audio.de/viewtopic.ph … 48#p216648

Mic cables don‘t have an exactly defined “Wellenwiederstand” / HF impedance, but for sure nowhere close to 75 Ohm.

Most balanced mic cables are in the 110 Ohm area, that’s the reason why this HF impedance was selected in the AES standard, and why analog mic cables typically work flawless as digital AES even at greater distance.

EXPLANATION:

Wellenwiederstand / HF impedance has nothing to do with DC / audio frequency resistance.

The effect of the HF impedance comes into play only if the transmitted frequency is high enough to form a “wave” inside the cable, for a 5 m cable i.e. that would be at ca. 10 MHz (10 Mega-Herz).

If the impedances of sender, cable and receiver are not matching, energy is reflected at the connection points, which can disturb transmission, if too strong.
Digital transmission can, up to a certain point, handle this disturbance, so a little HF impedance mismatch usually doesn’t hurt.

For analog audio frequencies HF impedance is of no concern, as no wave can build up in an interconnect cable.
Only exception: long distance overland telephone lines, where the reflection can create audible echoes.