BAT or Pass With My Sophia 2s?

From a thread discussing Pass Labs XA-30.5.

06-13-10: Madfloyd
I haven't had good experience driving the Pass with tube preamps. I've tried the Cary SLP-05 and the Audio Valve Eclipse and the low bass is rolled off. It's one of the reasons I got the Bat.

Both the Cary SLP-05 and Audio Valve Eclipse have output impedances that rise to 3400 ohms and 3090 ohms at 20Hz. Not good when matching with an amplifier having an input impedance of 20k ohms/30 k ohms (single ended/balanced) as does the Pass Labs XA-.5 series.

Match a tube preamp with a low output impedance (below 300 ohms, IMO), and you will have an excellent match with Pass Labs XA-.5 series amps.

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.

I am very happy with my BAT VK-52SE tube preamp and BAT VK-600SE amp driving a pair of Wilson Sophia 2's. The bass is one tick less tight (but still very good) than when I had a SS preamp, but the midrange and treble is much better. Unfortunately, have not compared Pass gear, so not much help on that point. Good luck!