Originally Posted by Kiwiburger
Just because a cable is passing a digital signal doesn't mean it isn't susceptible to ground loop hum. But I believe it would manifest as jitter and clicks and pops - and affect left & right equally.
If it really was a ground loop hum, the same principles of isolation or disconnecting a redundant ground connection apply. Neutrik make these great inline transformers that turn s/pdif into AES, so you could run balanced cables even for your s/pdif stuff. The transformers should block any ground loops.
But I suspect this hum is in an analog stage somewhere, not digital. But it could still be the ground connection via the digital cable that is causing it. So I would try the transformers, since i've got them. I think every studio should have these transformers anyway, so might be worth a punt.
Hmmmm, try hooking up analog and see if the hum happens. If it does, and its still on the left, yer ART is hosed. If not, maybe yer expensive (screw Monster cable!!!) spdif cable is a POS.
I like Canare cable....