musical fidelity 3.2 cdp + x10v3 vs. JOLIDA 100

If it were me, I'd dump the Adcom for a tube pre amp before doing anything else. I think you'll find that move a better way to test the tube waters.

My view is definitely go for the 10v3. And include the matching power supply unit as well. I recently added this combo to my system (Pioneer LD/CD player; Krell KRC HR pre Krell FPB300c power-amp & Monitor Audio Studio 20SE speakers) and it transformed the Pioneer CD (a competent, versatile but not outstanding unit) into a giant killer. I should add that my normal front end is a modified Esoteric P700 transport feeding a MF Trivista 21 DAC and the Pioneer with the X10v3 virtually matched that of the P700/Trivata 21! In fact, if one is really into the 'tube sound'; you can even tag the X10v3 between the 21 DAC & pre-amp to good effect.
The X10v3 with MP 3.2 player should give a performance on a par with the Trivista 21, which in my view, is one of the best DACs around at the moment.