Theoretically, this is impossible, unless the Wadia has a fault that a pre-amp can fix or disguise. You won't have to have tried it to know this basic fact. You're looking in the wrong direction.
My Only Question Is.........
Would someone please tell me the name of the preamplifier(s) on this planet that when inserted into the signal path between any recent Wadia cd player and any amplifier, IMPROVES upon the sound of the forementioned Wadia when compared to running it direct using its digital volume control near its peak. Remeber contestants that the better the preamp the less it imparts to the signal. Keep in mind also that answering this question intelligently would require that you have actually tried this.