Disappointment with Pass Labs - I'm looking for something else

If you do go with the Pass X250 and AR Ref 5 pre ... take a close look at the gain matching. I have Pass XA 60.8, AR Ref 6 and Avantgarde UNO speakers.  The I love the sound of my setup but I can’t turn the volume control past 5 without blowing my ceiling off (so to speak).  I had to add attenuators.

I know AR preamps have a lot of gain. In my case, when I tested an LS27, with the "low gain" setting I didn't have that problem.

I have Crites speakers which are quite similar in sound and setup to the Cornwall IV.  I use the Pass XA25 and find it to be quite neutral sounding, dynamic and great imaging.  I don't use a preamp. The 25 does not have 2nd harmonic distortion voiced into the amp.  This could be what you are hearing.  Also, I spent months positioning the speakers.  But it ended up being quite simple.  Point them so a line directly from center of each speaker intersects about 12 inches behind your head(not exact)  I also used the Vandersteen setup method.  This makes sure your speakers are not the same distance from the side wall as they are from the back wall to minimize phase and comb filtering.  I then had to add bass traps and diffusion panels.  This will really clean up imaging and bass definition.  Sub woofers can also open up the mid range. 

I did not care for tubes.    Muddy bass. 

I too wonder which preamp works good with this setup.  A tube preamp is often used but I would be asking which one just like you.  I am not sure a preamp would make my system sound better or not. 

I hate to see you start over.  It is frustrating and lots of work.  I see Ayre, Luxman, Accuphase and Sugden as solid state alternatives.  Based on reviews even expensive SS amps can sound too dry and clinical if you're not careful.  These alternatives I have listed would be Class A with a warmer presentation.    You do not need a big amp to drive these speakers.  The 30.8 actually puts out well over 100 watts and will break your eardrums before you break the speakers.  LOL

Yes, I know.

Another option is to see how the XA30.8 behaves when it comes out of Class A to go to A / B if I decide to switch from much less efficient speakers. I don't know if I read one day that Nelson commented that he went from accentuating the second harmonic to the third. Nor do I know if it will sound more forceful. I doubt it.

agree with many above....it is Klipsch.....

Yes, it is true that Klipsch are not high definition speakers. but this should not hide that the XA30.8 has a forcefulness problem and especially the XP12 have a resolution problem.