Pass X1 or BAT 51 SE to drive Pass Aleph 1.2 ?

I have a pair of Pass Labs Aleph 1.2 driving Egglestonworks Andras 2. The preamp is a CJ Premier 14 with unbalanced interconnects which I want to change for either a Pass X1 preamp or a BAT 51 SE to get more dynamics and soundstage. I will also establish a balance connexion. Does anyone have any experience with those two ? Any recommendation ?

Thanks for your help.