your love affair with balanced circuits is legendary. are you wrong about them? no. are balanced circuits the ’main thing’ about how circuits might perform? no.
balanced circuits = one advantage....but not the whole ball game....which is what you are saying. and that cannot be known. we all can have an opinion about it though.
the best performing systems i have heard up till now have not used balanced circuits. which proves nothing either. since that aspect of a system is not dominant in it’s performance....one way....or another.
(emphasis added)
My comments were about balanced line operation- the use of balanced cables in audio. Not so much about balanced circuits in audio equipment (that is a different conversation which I avoided).
That balanced lines when supported by AES48 are superior than any RCA connection is both measurable and audible. There is more than one advantage. Since I don't know which you were referring to I'll name a few:
* no ground loops since ground is ignored and used for shielding only
(this means if you get a ground loop with balanced lines AES48 isn't being supported)
* prevents coloration caused by the interconnect cable
* lack of colorations (including high frequency roll off) allows for longer cable lengths.
* since the crux of the operation lies with the associated equipment, the cable itself can be quite inexpensive
* Since the associated equipment will have a high Common Mode Rejection Ratio (CMRR) noise impinged on the interconnect cable is rejected at the input of whatever its driving. This isn't possible with a single-ended connection so you get lower noise.
OK I've listed 5 advantages and there are more.
My recommendation as always with this sort of thing is to try it. Phono cartridges are already a balanced source and most tone arms are wired balanced so this is really about the interconnect cable and what is receiving it. SUTs, being transformers, can run as a balanced input quite easily with very high CMRR values. Their output can be single-ended (this is why transformers are good at converting from one to the other). So this would be an easy thing to try.