This very much depends on a few factors.....
1.The quality of any partnering pre-amp being up to the same or higher level than the source.
2.The output stage of the Wadia being either unable to drive the input stage of a given power amp adequately,or of poorer performance.
3.IIRC,the volume control of certain CD players,and I think the Wadia included,worked in the digital domain,and did so by truncating the bit length,resulting in decreasing sound quality at very low volume settings.
If this is true,then using a separate preamp may well be beneficial,but you would need to be certain of this first.
You could certainly try auditioning a few decent preamps,and would need to be looking at those from the likes of Krell,Levinson,Conrad-Johnson etc to get similar levels of performance.