question about Balanced signals.

What is the purpose of a balanced circuit. If you want it to reduce hum and noise you need a differential input. The signal does not have to be differential but both legs need to have the same output impedance to ground. The input must have the same impedance on each leg relative to ground but should be lower than the input impedance of the driven device.

All of those criteria are met in a proper balanced circuit. 

Dear @dukebdevil :  I have  serious  doubts that your amplifier be a TRUE balanced design as you posted. Please read these:

" The voltage gain (into 8 ohms) was 28.4dB via the unbalanced RCA jack. This is slightly on the high side for a THX-certified design, but 6.7dB lower via the balanced XLR jack, which is very unusual. "

That was measures by in real time by STHP review ( J.Atkinson. ).

Additional to that in the manual operation Rotel stated:

" Rotel's balanced design. "

A true balanced design is only that a true balanced design but not Rotel's or Luxman's or whatever manufacturer name.

I think could be better that you forget about your OP with this amplifier.

R.

The best man to answer your question is Atmasphere. He practically made 'True Balanced' equipment the norm when most manufacturers only offered RCA.

Bob

@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".