Some folks use unshielded interconnects, ie. UTP ... Unshielded twisted pair. Nothing different than what you did if you lifted the shields at both ends, other than the fact that UTP has no shield in the first place. As I mentioned in another post, Shield twisted pair cables are commonly wired with the shield only connected at one end, usually the source end. Many cable manufacturers make their cables this way. I would dare say it's probably the most common cable these days.
Just curious as to whether you lifted the shield at both ends? If so, you can try connecting it back at the source end only. This should give you some benefit to the shielding without bringing the hum back.
Just an example, a short read from Van Den Hul ... http://www.vandenhul.com/userfiles/docs/Ground-End_Marking_Stickers.pdf
