Anybody using Wilsons or Soundlabs with Pass Labs?

Yes - I did. I tried a Pass Lab X600 with a pair of Sound Lab Auras (similar to Milenium series, but made of steel like Ultimate).

I also got to compare the X600 with Krell KSA 300S and Atma-Sphere MA1 mkII.2 OTL tube amps.

The results:
Atma-Sphere had the overall best performance, with the Krell a distant second. The Pass amp had NO BASS whatsoever to speak of. I suspect the Pass amps do not like the high impedances that occur in the mid-bass region.

DO NOT recommend you pair the Pass amps with Sound Lab speakers. However, I will say that the midrange and upper frequency performance was outstanding.

Wow! what a lot of interesting responses. I would have never guessed the Aleph models could give satisfactory service on the big speakers.

I have a pair of Wilson W/P 6 and tried a Pass 350 when I was looking for amps. The Pass was a very nice amp but just didn't do it for me. There was nothing wrong but I felt the magic wasn't there. I ended up with Atma-Spere MA1. The only thing I can suggest is giving them a listen.

Ferrari, Did you see Roma's post (Should I sell my Diva?) Could it be there is a dichotomy in perception when it comes to bass response? Shall we say, hi-fi bass, found only in audio, epitomized by truck bed mounted mega woofers, versus natural bass - like the baritone and kettle drum. I would want an amp that gets the texture and timbre of these big wave producers right rather than an amp that will substitute accuracy for cracking the plaster. My X-600 is of the former.

Fdriver has an interesting perspective. One could order/update with the SL biamp option. One could then put Alephs or X series amps on the top end and perhaps Wolcotts on the bottom, or MAs if you wish. Or even 4 channels of Pass amps, if your electrical system is up to it. I believe the new crossover configuration offered as an update by SL would lessen the bass taste issues some of the correspondents cite. I feel recordings vary in bass impact much more than the excellent electronics all the correspondent refer to. Others, credible others, have used the Sunfire 300 watt on the bass and the Wolcotts on the top. HAve fun!