question about Balanced signals.

@rauliruegas thank you for locating that info.  agreed, everything I have read about Balanced says you gain about 6dB of gain over unbalanced, not lose.  this helps explain why we were confused when trying the PSA Dac Jr as a preamp.  it was too wimpy with SE, someone suggested that it should be stronger with balanced so I got a pair of XLR and it was even lower output.  I guess to Rotel, dual mono (who isn't) and the inclusion of XLR jacks with a "balanced" or "unbalanced" switch is "Rotel Balanced". 

@atmasphere  sorry was trying to sum it up without going into details (because that is where we tend to make our technical mistakes).  In this last post, I should not have said "cable" .  As you clearly are aware, it is the whole design that contributes to less noise relative to signal (conversely higher signal to noise ratio).

@atmasphere Thank you for the xlr cable suggestion.  I too like to save money and even if on short runs, an unbalanced cable is able to sound "clean", that cable is likely to be much more expensive to get similar performance to the balanced path.

audio-gd responded that "The preamp convert the SE input to balanced output.".  

without getting into the weeds, it seems there is one highly desirable outcome of balanced/differential circuits.  A balanced cable will have less noise, giving a higher signal to noise ratio.