I did some digging and found standard wired XLR mic. cables aren't the best choice for line level component and powered speaker connections. XLR balanced outputs are wired different by different manufacturers as it relates to ground pin 1 (signal ground) and the conector case (chassis ground). Most all Mic cables are wired straight that is the +pin2, -pin3, and shield gound pin 1 are the same on both ends. This is great for microphones, but not line level signals. :cry
This creates a ground loop between line level components.
For the worse case senario consider powered speakers. Your mixer, cd players and such are plugged into one A/C wall outlet and the speakers are plugged in to another wall outlet. All is well if all of the outlets are off the same circuit breaker. If they are not you might get a hum, buzzes and junk.
You can spend $50-$200 on ground isolators, humbuckers, and directboxes. They all do the job but I like to make $$$ not spend it! Plus the more components in the signal path the better the chance of something breaking or screwing up the sound.
:idea In my research I have found out how the broadcasters deal with this. All you have to do is mark your Line level cables as line level only. Then cut the ground (shield) off at the female end. The rule is ground only at the destination end NOT the source end of the signal path. So only the signal +pin2 and -Pin3 should be soldered at the female end. This is called isolating. As you see you still have the huge noise canceling benefit of balanced lines without the potential ground loops.
:confuzzed I found alot of info in the appendices of the my APHEX compellor owners manual. There is also info how to interconnect -10 unbalanced lines to +4 balanced inputs and vice-versa.
For the details. Start reading at page 28. :tup
Aphex Grounding PDF
Linear Mode
