BAT or Pass With My Sophia 2s?

I have both: a pair of Pass XA 100.5 monoblocks and a VK-600SE.

My speakers are Wilson Sophia 2. Preamp varies between SS and tubes (I'm still searching...)

Both are great amps. The differences to my ears:

Pass:
- Better midrange
- Thicker, more tube-like bass
- Warmer presentation overall, not much in the way of 'air', but highs are very smooth

Bat
- Bass is much tighter, less overhang
- Midrange and highs not as smooth as Pass
- Leaner presentation with much more air

At the moment I prefer the Bat, but both amps are great.

Meant to add that if you're going with a tube pre, the Bat would be the one I recommend.

What Tvad says is true. If you go with the Pass, you need to be careful to find a preamp (that you like) that has low output impedance.

I'm picky about preamps and I've gone through several in the last couple years.

I have no experience with any of the Bat preamps (although I'd like to try them).

I'll be auditioning a Joule over the next week.