Anyone have any advice?
3 responses Add your response
It's the components that need proper grounding to prevent ground loop, not the cable. RCA interconnects have no ground wire and XLR has that 3rd grounding wire. But that is to help protect against RF and EMI.
You mention Earth Ground...it's your amp that needs it. And only one component should be earth grounded. Grounding more devices can lead to ground loop.
You have to understand how the shield works. Interference can be capacitively or electromagnetically coupled. In first case it is straight forward draining interference to ground. In case of electromagnetic interference lower frequency coupling is prevented by the cable lenght, that has to be 1/10 of wavelength to be an effective antenna and by the skin effect for the higher frequencies. Non-magnetic shield cannot protect against electromagnetic interference so interference is being induced but because of skin effect it appears on the outside layer - the shield. Equivalent field inside of the shield is zero. As for grounding - shield should be grounded at one end (but XLR shields are grounded at both) and every component that requires grounding should be grounded (in star fashion) to common ground point. That's pretty much safety requirement.
Electron flow does not play a part since electrons are not moving at AC (vibrating in place). Electric charge is moving back and forth but when it comes to delivering power it is not even by the cable but rather on the outside of the cable by electromagnetic field (called Poynting Field).