In short, a balanced audio connection uses three wires instead of two (like in an unbalanced line). Two of these lines carry the signal (one "normal", one with inverted polarity), the third line acts as the shield (and is connected to the ground).
If noise (hums, buzzes) is induced into the signal lines, it can be canceled out at the receiving end by simply subtracting the two signals (normal and inverted) from each other.
In Recording, balanced lines often come in the shape of cables with XLR (three-pin) and TRS-Jacks (which can be easily confused with unbalanced stereo lines, because the plugs used are the same as regular stereo Headphone jacks)

More in detail, and most probably using more accurate tchnical terms:
http://en.wikipedia.org/wiki/Balanced_audio

To expand on what NoNoise said: balanced connections are differential, that is, the signal is formed from the difference between the two signal conductors. Interference that is common-mode, that is, induced equally in the two signal conductors, will cancel out in the differencing process and so will not corrupt the signal.

This topic may be helpful to you:
(Dead Link Removed)

So what exactly is the difference between a stereo 1/4" and a balanced 1/4"?

Balanaced, as said above, uses 2 cables to transmit the signal (plus the ground cable).
Stereo, uses one for the left and one for the right (plus the ground cable).

Stereo 1/4" has the left and right channels of a stereo signal on the tip and ring, with the ground being on the sleeve. It's unbalanced, because there are (presumably) two different signals in the two + conductors, with ground as common.

Balanced 1/4" has the same mono signal going through both tip and ring, with one of them 180 degrees out of phase, with ground as common. At the destination, one signal gets flipped 180 degrees back so it's now in phase. This has effectively eliminated most externally-induced interference along the cable path, plus it boosted the signal back up when it got flipped back because they now add together (oversimplified...but kinda).

They both use 1/4" TRS jacks and plugs. It's not the connectors that make the difference...it's the wiring and application of the connected devices.

Or...something like that... :shock:

Kapt.Krunch

Hey Codemonkey...I see you list a Ground Loop in your equipment. What brand do you recommend, or can I make my own? :roll:

Cheaper to make your own. Just run an extension parallel to and touching your snake, plug it into the oldest wiring system you can find and use unbalanced leads for everything (execpt mics but by all means, feel free to unbalance the signal before connecting to the snake box).
This won't cost you much, just the cost of an extension lead, and the irritation if you have good headphones to monitor with.

The only reason I get away with it is that the speakers are too powerful for the church and I can keep the levels of everything down.