hi, i have never tried the xa25 without a preamp but i have gone the passive preamp route before and did not care for the sound vs. a dynamic energetic preamp.
btw i have the cary slp 05, not the 98.
sounds just burst and project into the room lively and without strain. no DAC that i have heard or even many linestages can compete. expensive yes but hearing is experiencing. shortcuts are just that, they can sound fine until you hear something else.