By changing from rca to xlr, you have changed the configuration of the dac's output circuit that is being used, the configuration of the preamp's input circuit that is being used, gains and signal amplitudes (and therefore presumably volume control settings), susceptibility to ground loop effects, susceptibility to pickup of low level noise, output and input impedances, and probably the relative amplitudes of some harmonic distortion components. The make and model of the specific cables have nothing to do with any of those things; they are just one more variable among many.
Definitely an apples to oranges comparison, as was said above.
Regards,
-- Al
Definitely an apples to oranges comparison, as was said above.
Regards,
-- Al