understanding when and where to use balanced vs unbalanced

  • Thread starter Thread starter Nick The Man
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The relevant sentence of that wiki appears at the top:

"The factual accuracy of this article or section is disputed."


The original meaning of balanced was that both sides of the circuit had the same impedance so that interference (noise) would appear at the differential input at the same amplitude, and therefore be rejected. It had nothing to do with signal symmetry.

It has become common belief and usage that it has something to do with inverting the signal on the second conductor. Which is fine, as long as you understand that signal symmetry has NOTHING to do with noise rejection.

One really effective balanced output is called the impedance balanced output. The second conductor isn't even hooked to the output device. It's hooked to grounded through a resistor.
 
You are absolutley right that a Balanced signal doesn"t have to have audio on Pin 3 (of a XLR) so it is the Impedance seen by the diferential input that canceles out any Noise that is picked up by the cable or other sources.......

There are Generally 3 types of Balanceing, Transformer balanceing and Impedance Balanced and there is also a third type of electronic balanceing which in a way emulates Transformer Ballanceing (Inverted Phaze on pin 3).....

Here is a Good page on Balanced audio which seems to be Fairly accurate......


http://www.dself.dsl.pipex.com/ampins/balanced/balanced.htm
 
TexRoadkill said:
Well it does mean one or the other :p
No, you can use a trs cable to connect two unbalanced pieces of equipment.

The cable is neither stereo or balanced, the signal it carries is. A TRS cable is capable of carrying a balanced or stereo, but the signal has to be balanced in the first place.
 
Farview said:
No, you can use a trs cable to connect two unbalanced pieces of equipment.

I was referring to situations where TRS cables are actually called for.
 
boingoman said:
It has become common belief and usage that it has something to do with inverting the signal on the second conductor. Which is fine, as long as you understand that signal symmetry has NOTHING to do with noise rejection.

Then what is the point of that type of balancing?
 
Just to make this all even more complicated, lets put an end to the +4, -10, balanced and unbalanced thing....

+4 does not mean balanced, and -10 does not mean unbalanced.

Balanced cables are perfectly capable of passing -10 and unbalanced of passing +4. It is common for +4 to often be balanced and -10 to often be unbalanced, but it is not necessary:)
 
TexRoadkill said:
I was referring to situations where TRS cables are actually called for.
That is why a lot of people get confused about this. Someone blurts out half the story and makes it sound like it's the cables that are making something happen when they aren't.

You can use a TRS cable in any situation and the signal will be what ever it is. If you use a TS cable, the signal coming out of it can only be mono or unbalanced.
 
TexRoadkill said:
Then what is the point of that type of balancing?

Hey- I've been meaning to post a reply, it's been a ridiculous week for me. I'm working on it, though. The short answer is "I'm not 100% sure, I have some guesses and a couple other things to say."
 
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