question about Balanced signals.

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". 

@dukebdevil If there is a 6dB increase in gain by going balanced, then the equipment does not support the balanced standard (AES48). The reason this is important has to do with your opening question about the best interconnect for the money.

If your equipment supports the standard then the interconnect will cease to be important. It will simply work and sound correct. And if the equipment supports the standard then there will be no 6dB gain increase as well.

There are three ways to do a balanced output: output transformer, a solid state circuit that can sink current and float at the same time, and the method we patented using a Circlotron. Inductive sources, like a phono cartridge are balanced sources. So think about this: if you apply a phono signal to the input of a differential amplifier, will it make a difference if one side of the signal is at ground? The answer is ’no’ the total Voltage is exactly the same whether one side is at ground or not.

A phono cartridge can meet all the requirements of AES48 as a result. Does this clear things up?

So with this all in mind, Mogami Neglex is a good balanced cable for not a lot of money (I use them in my home system) that will keep up with any high end audio balanced cable of any price so long as your equipment supports AES48. To me this is a big deal since high end audio cables can cost north of $1000/foot! My cables at home are 30 feet long and cost about $300/pair. If $1000/foot I’d be looking at $60,000!! For no difference in sound that’s pretty significant. Capishe?