What's a good alternative to Pass Labs?

In my experience the older Coda amps were very good and yes they do have a warmth to their presentation. I certainly haven't heard all the newer amps, but I have heard the 15.0 that Ren mentioned. It does have a rich midrange presentation, but I would not call it warm, rich and layered, yes. Not warm...

IMHO, the issue is not the X250.5. Rather, the Pass amp is revealing issues elsewhere in the chain, most likely upstream: source/pre-amp/dac.

You may want to RE-visit the review of these speakers. The reviewer says that they are "shouty" at higher volumes. You may be sensitive to this region of hearing frequency??? I think the perceived bass warmth comes from the transmission line architecture. You just will not get the tight/taught response from the drivers with large surrounds and there is an 8" line/port that helps to reinforce the bass, but causes timing issues with the mid bass drivers which are faster. This may cause you to lose some detail/resolution.

Do you always use the JL subs when listening? (they may be faster or slower than the main drivers). Integration can be tricky.

Hey Tom6897, can you link me to the review that called them shouty? I don't think I across that one.

I'm familiar with your amp and preamp. Your issue is your preamp/dac. I think this is the 1st time I've ever heard anyone describe the x250.5 as bright.

I'm not familiar with your speakers.

If you want a forgiving amp, look for so,etching with tubes,,but not AR