I'm not stating an overarching disparagement of usb, in many cases usb may outperform I2S, I keep on reiterating my experience with Singxer SU6 vs usb. I will continue to affirm what I believe to be inherent advantage of dedicated lines for data and clock, and no need to convert from usb to native I2S within dac. Does it seem reasonable to believe extracting data and clock streams from one cable is an advantage, same with detour through usb boards. With I2S one is simply supplying isolated and dedicated clock and data streams directly into native I2S path of dac.
Now I agree the downside of I2S is the cable, however, I'm reasoning the superiority of the clock in Gaia over 006 clock supersedes or overrides the downside of clock being further away and having to travel through short cable to I2S stream inside dac. Superior sound quality I'm getting via I2S is provides evidence for this.
As for choices made by manufacturers in regard to interfaces, plenty of dacs provide I2S inputs including Rockna, Mola Mola Tambaqui, PS Audio, most of the Chifi, and some others I've seen listed on forum. More at issue here is the failure of streamer manufacturers to provide I2S outputs. With so few streamers offering this output easy to understand why dacs wouldn't provide for it. Now, as to why streamers don't offer it, here is how I see it. Virtually all off the shelf computer motherboards (which is what all streamers are) have usb capability on board. These boards were originally developed for general purpose, only in relatively recent years have they become optimized solely for audio. We also have follow the leader syndrome, usb became the de facto interface because it was no hassle to integrate, integrating I2S requires more work, another signal path, clock and power supply. I also agree it can sound fine since so many years and so many manufacturers working on optimizing it. I've used many usb optimizing solutions over the years, each subsequent solution bettering the previous. If I hadn't purchased Laiv Harmony with the specific intention of trying I2S with it I wouldn't have even bothered with I2S to 006.
As to doing away with a DDC altogether, I have option of installing Pink Faun I2S board in my custom build streamer, I'd power via my Uptone JS 2 choke based lps. In going this direction I'd completely eliminate my Sonore OpticalModule, OpticalRendu (no more optical network conversion and total elimination of usb, AQ Diamond usb cable, lps, AC cables, DC cables). Question becomes does less become more?
Finally, based on reviews of the world class streamers and dacs, I have no doubt the proprietary interfaces they use are superior to both usb and I2S. Still, the native signal path within dacs remains I2S so the ultimate solution is to provide a superior clock and power supply for that clock within the dac. As for the streamer I haven't researched these proprietary interfaces enough to know exactly what they do, however, it seems reasonable to believe they provide dedicated runs for clock and data, I can't imagine mixing up data and clock on a single cable is the optimal solution.
