Unbalanced and Balanced output voltage

Milpai,

The idea of balanced circuit is to separate negative signal from positive and from the ground. In conventional RCA unbalanced connection we only have one signal terminal and ground while in balanced circuit we have Negative, Positive signals and ground.

If RCA output in the same component let's say CD-player is specified 2V, than for balanced it's +2V on positive 'leg' and -2V on negative 'leg'. The total output voltage is sum of magnitudes giving 4V. Very simple math.

Thanks,

In my case is the other way around. I am using a Sony SCD-XA5400ES connected to a passive amplifier. From the RCA the volumen is OK but when I connect the XLR I have to turn the volume almost to maximum to get good sound. I do not think this is good because I believe that the impedance is also high. The Sony has 2 vols in both RCA and XLR. I wonder if the problem is the preamp that does not have any gain...

Marakanetz,
Thanks for explaining. It makes sense now - why I have the much wanted gain in my system. And I believe that it is safe to assume that when a manufacturer specifies 2V via RCA and XLR, it actually means 4V to preamp thru XLR.

Raulpjc,
I am surprised by what you are facing. What is your preamp and amp? Can you try one more thing? Connect the Sony to the preamp via RCA. Then connect the preamp and amp via XLR and see if it makes any difference. Let us know how this works.

Component must have a true balanced circuit otherwise having XLRs are just for adapter purposes. McIntosh amps/preamps are example of having XLR with no true balanced circuit.

I believe the same goes for my Parasound A21 amp. It is not truly balanced. But that gain worked it's magic in my system :-)