I have seen this before. Depending on the grounding scheme of the amps, you can get major buzzes from ICs - no matter the length. Getting around the problem may be tough. I had an easy way out with MIT T2 ICs, which never seem to buzz even with my sensitive Kora Aries and so I didn't experiment much on other ways to solve the issue. I would say any shielded cable could improve things but the problem is grounding, as you already figured out. I will think about it and if I think of anything, I will post again. Of course, MITs could solve your problem too. But lifting your ground should work. Hmmmm...
What preamp are you using?
Arthur
What preamp are you using?
Arthur