Great little converter/DDC. Bought two, now selling one. Xing has done OEM for Denafrips dacs so they have a solid rep. Works with Mac and Windows. This unit comes with AccuSilicon clocks. Runs on USB 5v or external supply (not provided).
This was used for the SPDIF output so can't help with questions about i2s.
$150. Paypal only.

