All true and valid points, Al. The balanced outputs in Tim de Paravicini’s EAR-Yoshino 868 pre-amp are created via output transformers (rather than integrated circuits or, heaven forbid, opamps)---which are widely used in recording studios, in which Tim does a lot of work. The pre-amp’s circuitry itself is single-ended.
And the balanced inputs in Roger Modjeski’s Music Reference RM-200 power amp are accomplished via some sort of resistor network, which Roger has described here on Audiogon. That description may as well have been, for a technically-limited music lover such as myself, in Greek. ;-) Unlike the EAR 868, the RM-200’s circuitry is fully balanced.