the ideal case in reality when the whole system is either balanced or unbalanced to take a real advantage of canceling the noise.
for a true-balanced preamp modification you will definitely need something more than directly soldering XLR receptacles and mounting them onto the chasis. you will have to know how to separate the positive signal wire from negative signal wire and the ground to take the full advantage. simply coupling negative signal wire with the ground will bring the same result as unbalanced RCA and simply adding a parasite unused outputs.
on the other side of that issue you might never know unless you open the amp and see how XLR plug is connected there before you make a conclusion that it is true-balanced amp or any component. in this case there is no point to modify and you'd be better of with differently terminated interconnects.
for a true-balanced preamp modification you will definitely need something more than directly soldering XLR receptacles and mounting them onto the chasis. you will have to know how to separate the positive signal wire from negative signal wire and the ground to take the full advantage. simply coupling negative signal wire with the ground will bring the same result as unbalanced RCA and simply adding a parasite unused outputs.
on the other side of that issue you might never know unless you open the amp and see how XLR plug is connected there before you make a conclusion that it is true-balanced amp or any component. in this case there is no point to modify and you'd be better of with differently terminated interconnects.