A protocol without error correction and without standardized connectors, which was designed for short connections between integrated circuits on PCB boards, where the designer can control spacing, line length, and impedance between components, thereby having control over timing and being able to ensure error-free transmission in the intended environments (hence being able to forego error correction).
Then some vendors in the audiophile industry started to market it for external cable connections between devices (often repurposing HDMI, RJ45, or BNC connectors with non-standard pin assignments) on the basis that it’s exotic and not the USB that the poor neighbors use, although cable connections don’t fulfill the design requirements for timing, impedance, and interference.
An I²S bus uses separate clock and serial data signals, for purely technical reasons of simplifying receivers on PCB boards (of which there can be many), but this proved useful in marketing to well-off consumers who don’t know that much about how things actually work.
My experience is that you can hook up a DAC to a ROCK/i7NUC. I have a Holoaudio Red as streamer with built in DDC that outputs to a Topping DS90 in my office and a Hermes 12th DDC directly hooked up to the NUC via USB, the DDC output is connected to a Pontus 15th. The latter works fine. I don’t see a reason why that wouldn’t work with a Nucleus. USB connections and PC’s are said to be “noisy” but that is where an additional DDC can help.
Yes, after a bit of research I’ve ordered the Fiio SR11. Hopefully the (far eastern) manufacturer will stay in business and continue to offer technical support for longer than a fortnight!
I have three, which are basic but appear to work just fine. I currently have them outputting over USB-C.
I left them on the M239 firmware, which is quite sufficient for Roon. The latest V630 firmware adds a bunch of features I didn’t need and might have risked stablity. Both firmwares remain available on FiiO’s site.
The initial configuration is a bit clunky, and one potential quirk when connecting to WiFi is that it apparently can’t detect 5GHz DFS channels.