After all the auditioning by the audio gods here, what is the final verdict on the fidelity between USB vs I2S on MK2?
I’m currently connected via I2S using AQ carbon.
Please advice. As always, a lot of appreciation to this forum, which has guided me to get best out of my system (with a “small” side effect of spending perpetually on audio from the day I met you all).
I recommend trying them both and using the one you like best. What everyone else thinks doesn’t matter.
With that said, I did exactly that and am currently using I2S.
would suggest whichever I2s you use, i would lean on glass for you cable construction…the purer the better…
According to Ted they are equal. But in my system, I found USB input sounds more “analog” than I2S. It could be that the cables themselves make more difference too because MK2 is sensitive to hearing cable differences. Also, there are way more cable selections in USB than I2S. I believe there are better cables in USB than I2S because few makes audiophile HDMI cables.
AQ Dragon48 is the best cable for I2S, but it is not a “warm/analog” sounding cable for sure. There are larger selections of USB cables that sound superior to it (from my own experience similar priced Stealth T-select and Shunyata Sigma will beat it quite easily). Shunyata Alpha USB is a great cable too.
I agree with Donald that they are very close. In my system, I2S via the Airlens just edges out USB, but at much greater expense…
I agree with Donald, when I used MK II I went for USB.
Is it even possible to answer this factually? Seems to be too many variables that can’t be accounted for.
A streamer that has identical outputs via both usb and i2s…in output level, jitter or any other parameter.
A usb cable and i2S cable that would sound exactly the same. Not sure how someone could even answer this objectively.
If someone can solve these variables first, then comes in a listeners personal preferences for what sounds “better.”
Ah, but for the fun of a hypothetical question we’ll all do our best to answer it. 
I can eliminate one variable. My previous streamer, Euphony Summus2, had both I2S and USB outputs, I2S HDMI output was its best output according to the manufacturer. But when comparing similar priced cables (AQ Dragon48 I2S vs. Stralth T-select and Shunyata Sigma USB), my clear preference was with USB link. This was completely opposite from DS MK1. MK2 has improved the USB input so much more than before.
My comparison in the DSD Mk1 was with a Nordost Valhalla 2 USB cable thru the USB input vs the Matrix 2 I2S converter thru the I2S input with a AQ Dragon HDMI cable, and it wasn’t even close. the I2S wins hand down! The DSD Mk2 is a different animal. The difference was much closer with the Valhalla 2 USB input which definitely has better resolution to the sound. The Matrix 2 is now in the junk pile. But when I got the ChordMusic USB cable, the MK2 took on another level of musicality. Yes, the cables you use can make a signicant improvment to the sound, but not enough to help the mediocare USB input of the MK1.