typeS5 said:
Thanks for the suggestion. I'll try it out once i have the time.
Also, what's the difference between a balanced/unbalanced connection? Haven't really found any good explanation as to what balanced/unbalanced really means.
Do you know how sound waves can cancel each other out? If a sound wave is, say, +1, and you make a copy of it, and invert it, so that is -1, and then you add them together, you get nothing at all?
Balanced connections use this principle to cancel out noise that is picked up by the cable.
Here's how it works:
On a balanced connection, the signal from the instrument (say, a mic) travels down the wire on two conductors/wires (not counting the shield). The same signal is on both conductors, but ONE of them is inverted. Lets call these two signals +S and -S.
Now as the signal travels down the long wire, electric noise can be picked up along the way (wrap a mic cable round a transformer and you get the idea). That noise arrives at the other end as well, and it will be the same on each wire. Lets call the noise N, and since it is not inverted, it is +N on each wire.
Now the two signals arrive at the receiving end. One conductor carries the original signal and added noise (i.e. +S and +N), the other one carries the inverted original signal and the added noise (i.e. -S and +N).
Now here's the magic part - the receiving device (like an amp) takes the inverted signal, and inverts it again, i.e. turning -S into +S, so that it now is +S and -N.
Now it adds the two signals (from the two conductors) together. Since the original signal, and the inverted+inverted signal are the same, the original signal is nice and strong (think of it as +S + +S = +2S).
But the noise that is picked up along the way faces a different situation.
Because the noise appears identically on both conductors (+N and +N), the inversion at the receiving end will invert the noise signal on that conductor (making it -N), and when it is added to the original signal (which also has that noise on it, but not inverted, i.e. +N), the noise is cancelled out (+N + -N = 0), leaving you with a nice, clean and strong signal, without noise.
Balanced signals can be sent over long distances, which is why you will always see them used at stage shows and studios.
Guitars are usually unbalanced devices, and serious noise makers (as are pedals). The longer the cable, the worse the noise potential. Which is why stage/studio engineers often plug short guitar cables into something known as a DI (Direct Injection) box, which converts the unbalanced guitar signal into a balanced signal.
On your mixer, both the XLR MIC and TRS LINE inputs are balanced. You can plug an unbalanced cable into a balanced connection and it will work, but of course you wont get a balanced signal.
But if you plug an unbalanced XLR cable (where pins 1 and 3 are shorted) and switch on Phantom Power, you could end up with a smoked mixer, or guitar, or both.
Hence take care.
