I've run a lot of cables as a manufacturer. Not only that but we made the first balanced line product for high end audio- the MP-1 preamplifier. Over the years one of the more obvious deals for an interconnect between the preamp and the amp has been the Mogami mentioned several times already on this thread.
If you know only one thing about the balanced line system, the thing to know is that its purpose in life is to eliminate interconnect artifact!
In order to do that the equipment that the cables are used with has to support the standard: pin 1 is ground, pin 2 is non-inverting, pin 3 inverting, but most of all whatever is driving the cable should be able to drive a 600 ohm load without ill effects, which is how all the cable artifacts are swamped out. Most high end audio manufacturers don't get that last part.
IOW if the standard is met, the cable and its length will hardly affect the sound at all- and will be far more accurate than single-ended. So if you are hearing big differences between cables, that is an indicator that you are not getting everything out of them they have to offer.
If you know only one thing about the balanced line system, the thing to know is that its purpose in life is to eliminate interconnect artifact!
In order to do that the equipment that the cables are used with has to support the standard: pin 1 is ground, pin 2 is non-inverting, pin 3 inverting, but most of all whatever is driving the cable should be able to drive a 600 ohm load without ill effects, which is how all the cable artifacts are swamped out. Most high end audio manufacturers don't get that last part.
IOW if the standard is met, the cable and its length will hardly affect the sound at all- and will be far more accurate than single-ended. So if you are hearing big differences between cables, that is an indicator that you are not getting everything out of them they have to offer.