The Rane Library has many interesting audio relaed technical documents. The most famouse of them is Note 110 Sound Systems Interconnections - it is a classic. Just few days ago I happened to look around at The Rane Library, and found some really interesting material related to audio systems and ground loops:
Grounding and Shielding Audio Devices document points out that the use of entirely balanced interconnection with both ends of the shield connected to chassis ground at the point of entry provides the best available performance. The document goes through several grounding practices. The Audio Engineering Society is developing a recommended practices document which also condones chassis-grounding balanced shields, among other things.
Pin 1 Revisited document tells that cable shields are essentially an extension of the shielding enclosure of equipment, and they should be connected directly to that shielding enclosure. To make equipment cheaper to build, manufacturers started connecting cable shields to the circuit board’s common trace, then took that trace to the chassis. The problem is that any voltage drop across the wiring that is common to both the shield current and the circuit’s path to ground will be injected into the audio circuitry.
SCIN: Shield Current Induced Noise tells about testing audio cable shielding properties on different cable types and different frequencies. The article also covers induced cable current effects. The article details this testing arrangement for testing SCIN: