Ralph,
"Please note that balanced and single-ended are inherently incompatible! You can’t be both at the same time- its either one or the other."
You can feed a single ended signal into a fully balanced preamplifier, ground the negative (inverting) amplifiers positive input - connect the two negative inputs of both amplifiers (non inverting and inverting) together and a balanced signal will appear at the output of the preamplifier and the signal would be fully balanced from here on.
Don,
"I have always wondered why "almost nobody" buys (or even tries) inexpensive "pro" balanced cables, on the "true fully balanced" audio equipment, such as Pass Labs and ARC. They sound the same as the expensive ones IMO!"
Me too, the Canare L-4E6S wire offered by Bluejeans cable and other makes for a nice set of interconnects.
Good Listening
Peter