Balanced and Un-Balanced

[Artslap]

Hello,

 

Please excuse my ignorance.

 

What is the difference between Balanced and Un-Balanced Outputs and what is the advantage of the Balanced?

 

I have noted there seems to be three connections to the Balanced outputs. Is the third Earth?

 

I remember using the three pin connectors (XLR?) when doing AV stuff in the Theatre with Mics and whatnot.

 

Technical advice gratefully appreciated.

 

CP.

Edited August 19, 2013 by Artslap

[Zaphod Beeblebrox]

Hello,

 

Please excuse my ignorance.

 

What is the difference between Balanced and Un-Balanced Outputs and what is the advantage of the Balanced?

 

I have noted there seems to be three connections to the Balanced outputs. Is the third Earth?

 

I remember using the three pin connectors (XLR?) when doing AV stuff in the Theatre with Mics and whatnot.

 

Technical advice gratefully appreciated.

 

CP.

 

A balanced system employs three connections:

Earth

Positive input

Negative input

 

An unbalanced system employs two inputs

Earth

Positive OR negative input

 

To understand the advantages of a balanced system one needs to consider the old fashioned ribbon cable used for TV antenna systems. Although such systems have been supplanted by coax cable (which is an unbalanced system), they worked quite satisfactorily. An unbalanced system relies on the shielding surrounding the active conductor to prevent noise from entering the system. For 99.999999% of domestic systems, this arrangement works just fine. Most professional systems employ a balanced arrangement.

 

In a balanced system, any noise which enters the connecting cables, will impinge on the +ve and -ve conductors more or less equally. Since the interference will be in-phase in the cable, it will appear to be out-of-phase at the load (amplifier). The interference will be (theoretically) cancelled out. This type of arrangement is useful when cables are run alongside noisy lighting cables and other electrically noisy environments.

 

As I stated before: For normal domestic systems, there is no advantage to using balanced lines, except for the inherent mechanical superiority of XLR connectors over RCA connectors.

[CraigC]

That mechanical superiority is a good reason, as is the earthing arrangement possibilities and also the fact that the earth pin engages prior to the signal pin when mating the connector, unlike a RCA ( what were they thinking?)

[betty boop]

That mechanical superiority is a good reason, as is the earthing arrangement possibilities and also the fact that the earth pin engages prior to the signal pin when mating the connector, unlike a RCA ( what were they thinking?)

 

just a point of note, have and still use a mix of rcas and xlrs. the only failures in all these years I've had is been with xlr cables and xlr sockets. in which case both cables and sockets have had to be replaced. while more robust they are also more complex...and hence also more prone to failure..unfortunate but true...and this is in a domestic setup

 

agree re the earth. cant hot swap rca's ! not that probably a good idea to hot swap xlrs either ! hehe

[ellrotts]

That mechanical superiority is a good reason, as is the earthing arrangement possibilities and also the fact that the earth pin engages prior to the signal pin when mating the connector, unlike a RCA ( what were they thinking?)

 

whats wrong with that? its not like we hotswap anyway, even with XLR's

[Juicester]

we should throw 'quasi-balanced' into the mix....   that seems to be the third 'pillar'....

[Newman]

A fully balanced output also allows 6 dB higher signal level from the same basic circuit.

 

It is also less susceptible to ground loops.

[LunA]

I am no technician but I believe single end sounds more natural than balanced! I tried it myself and I never like true balanced design.  That is only my opinion! 

[Juicester]

I am no technician but I believe single end sounds more natural than balanced! I tried it myself and I never like true balanced design.  That is only my opinion! 

 

i guess it depends on the specific implementation of the balanced design you're referring to!! there are so many variables....

[Newman]

The main problem I find with balanced outputs isn't the balanced output, it's the corresponding input! (looks around room in confusion with 3-pin connector in hand...)

[andyr]

we should throw 'quasi-balanced' into the mix....   that seems to be the third 'pillar'....

 

What do you understand by the term "quasi-balanced", Juicester?

 

Andy

[betty boop]

What do you understand by the term "quasi-balanced", Juicester?

 

Andy

 

I think he means fake balanced. ie not really balanced design, just usign xlr connectivity.

[andyr]

I think he means fake balanced. ie not really balanced design, just usign xlr connectivity.

 

Let him speak for himself, al.

 

Andy

Edited August 20, 2013 by andyr

[metal beat]

I think he means fake balanced. ie not really balanced design, just usign xlr connectivity.

 

Is shoving a transformer into the circuit to make it balanced fake?

[Juicester]

I think he means fake balanced. ie not really balanced design, just usign xlr connectivity.

+1. As in, comparing examples, the Modwright LS100 (fake balance) and the Modwright LS36.5 (Real balanced).

 

Chris

[Sir Triode]

Is shoving a transformer into the circuit to make it balanced fake?

 

Yes. The circuit has to be balanced not SE converted with a transformer or IC.

[WhakPak]

Explained here:

http://en.wikipedia.org/wiki/Balanced_audio

[Newman]

I disagree, I think. The OP is about balanced outputs, not balanced circuits specifically.

[Juicester]

I disagree, I think. The OP is about balanced outputs, not balanced circuits specifically.

i disagree - i think the OP didn't necessarily know enough to think that the circuit and the output could stem 2 different conversations. In asking about the 'benefits' of balanced - i think it's pretty obvious that the OP is referring to the circuit (not just the outputs).

[andyr]

i disagree - i think the OP didn't necessarily know enough to think that the circuit and the output could stem 2 different conversations. 

 

3 different conversations, perhaps - in that there are also interconnects which are known as "psuedo balanced"?     These use "twinax" rather than coax - ie. there are 2 signal wires under the shield:

• one wire carries the signal
• the other is signal ground, and
• the shield is connected at one end only, so does not become part of the signal chain, merely acting as a (grounded) shield.  There are 2 ways of connecting this shield to ground: by soldering it to the barrel ... or (better, IMO) extending the shield into a pigtail which can attach to the (source component's) earth terminal.

 

Regards,

 

Andy

[Addicted to music]

Christ,,,

 

I thought you guys where referring to my internet bank account