@mitch2 I previously owned Singxer SU6, this with Musetec 005, preferred usb over my OpticalRendu vs I2S with the Singxer. Now have Denafrips Gaia with Tubulus Ximius .5M cable, prefer I2S vs usb for both Laiv Harmony and Musetec 006. This with a much improved usb board in 006 vs the Amamero in 005, Harmony usb nothing special.
Gaia superior to Singxer in usb isolation on input and implementation of OXCO clock on I2S. Singxer SU6 as good as it is, simply doesn't play in same universe, build quality, design, parts quality in Gaia all far superior. Meaningful improvement in sound quality reflects this superiority, and the Tubulus cable I'm using provides another substantial and meaningful improvement. A lesser optimization of I2S than this may change equation of which interface superior.