What is the advantage of a balanced interconnect?


How does a balanced interconnect work (perform) as opposed to a regular interconnect?

I've been out of the "market" for a while and am a little behind. It seems "balanced" is better; however, one guy told me that unless I am running long lengths I don't need to worry about balanced interconnects. Equipment would be NAD or Parasound CD Player, undetermined DA Converter (the $3,000 question), tube monoblocks, and Magneplaner speakers (probably just 1.6's). [I think I hope to purchase a DAC with a volume control and run the interconnect directly to the amplifier - no pre-amp. I think.]

A quick primer on balanced interconnects would be appreciated. Thanks
delsfan
Balanced will null out the 2nd harmonic and have 6db more gain....The system will be cleaner.....Used a single twisted pair and a double twisted pair of the same wire for the tests (SE vs Balanced) between the Blowtorch and JC-1s.....
Rwwear...How do I go about evaluating a device that eliminates inaudible noise?
I have not reviewed the suggested thread so this might be redundant: Another factor is that many amps with balanced inputs are not really balanced at all. They just provide the inputs and then internally convert the signal to unbalanced.
The 2nd harmonic is one after the first harmonic, and two before the fourth harmonic.