... moved it here, seems more appopiate than the iggy impressions thread ...
I'm using a Gustard U12 (HDMI I2S) and thinking about a Melodious MX-U8 (Cat5 I2S) ... basically because it looks better
. Both are very popular nowadays, very good according to a lot of users and peanuts cheap ($150-250) in hifi terms.
I did not personally test I2S but you can look into the U12 thread, many swear on it being better with various DACs. Maybe it is. For me it is just something I'd like to have/try at some point and more of a theoretical/whatif question. Many industry people complain about USB (mostly with good reason) but I do not see anyone trying alternatives.
I2S may be one ... yes I know about the short-cable limitations but you can easily stack a DAC and a miniPC.
Or maybe PCIE cable out of the PC with the pcie-i2s converter inside the DAC .. similar short-distance issues but you have the converter inside the DAC an can isolate the crap out of it. IIRC, the phasure DAC designer tried this but went back to USB (not sure why, maybe someone can clarify).
Or ethernet ... send audio data over the network cable (much better for this purpose than USB) and just add a network endpoint & ethernet-to-I2S converter inside the DAC ..something as small and cheap as a raspi can do all that.. and in any case such a solution should not be harder/costlier than this contraption https://www.silabs.com/products/interface/usbtouart/Pages/usb-to-i2s-digital-audio-bridge.aspx
Any of the above could be (in theory) better than the current PCIE-USB-(SPDIF-)I2S chain. And I'm sure there are other solutions, maybe much better. There are lots of people doing interesting experiments on dyiaudio or in android/raspi communities, but even if they have the right plan/idea, most have neither the tools nor the expertise of a hifi vendor. OTOH, the hifi vendors (even more progressive ones like Schiit) dont seem to do anything but complain about USB.