Unbalanced and Balanced output voltage

Here is more info..

My amplifier is McIntosh MC252 and I using as preamp, the DAC Grace Design m903 which is in fact a passive preamp (in reality it has a little gain). When I connect the Sony RCA to the preamp and this XLR to amp I get good volume, pretty loud at 3/4. When the connection is XLR all over, the volume has to go at over 90%. Connecting the Sony XLR and the preamp-amp RCA shows the same problem, which makes me conclude that is the voltage output of the player.

But, with the Oppo 95, the problem does not exist even thouhg the volume hat to go higher for XLR than RCA, let saa fro 60% to 75% versus 90% with the Sony XLR.

I have the feeling that there is a mismatch but do not know where...HAs anyone tried the Sony throughout XLR, impressions? THanks

When using a Wadia cd player's built in digital volume control the loudness levels are the same regardless to whether the RCA or XLR out puts are used . But I was under the impression that they used a 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 :-)

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.

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.

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...

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.

Elizabeth,
Thanks for explaining. I was aware of the amp's output, being limited to the spec. It was about a new CDP (in future) with XLR in my system that I was thinking about.
So does it mean that if the CDP outputs 2V per leg, that is equal to 4V to preamp? And then this 4V becomes 8V when it is sent from preamp to amp connected via XLR? This could mean trouble, as it would lead to too much gain in the system.
Yes, I do have to reduce the position of the volume knob when connected via XLR. When using RCA (between preamp and amp), my volume knob was at position 12-14 (depending on recording level) out of the available 24 positions. Now I have to go down to 7-8 to listen to comparable volumes.

Great question, Raul. You beat me to it. I was thinking of posting this today.
If someone can also answer the "leg" of XLR that I discussed a couple of weeks back. I have also noticed the same thing as Raul. 2V vs 4V. Is it that:
1.Some manufacturers do not prefer the "leg" approach and provide the "total" of "2V+2V" = 4V as the XLR out to the preamp
OR
2. Some manufacturers provide the figure of "2V" at each "leg" of the XLR to the preamp?
The reason I want to find is, when I switched from RCA to XLR between the preamp and amp, I got [substantial] gain. And some folks did mention that the gain "doubled". So whatever volts were going from preamp to amp - are they sent twice over + and - "legs" of the XLR?

the true balanced compoonents most-likely will have double voltage out of XLR. in case with RCA the voltage is measured between ground and positive while in XLR the voltage is measured between positive and negative pins +2v and -2v with respect to ground.