@antigrunge2 I have continued to successfully use a USB hub, but didn't forget your suggestion and found a used Intona Isolator to try between my Innuos Zen mk II and the Ayre Codex. Unfortunately it does not work at all and I cannot get a lock with any cables on hand. (Surprisingly it did provide an improvement when used from the Zen directly into a M2Tech Hiface with a BNC cable into my old Theta Gen Va.) I have no idea of the difference in galvanic isolation it provides compared to the USB hub.