@mesch
I am not sure that the issue I am having with my XA25 is typical to the model. I am not convinced that what I am hearing can be addressed with cables, break-in or warm-up. I have spoken to Pass Lab personel and have determined that my unit was manufactured last June and is still under warranty. If the issue is with my preamp I am confident Aric will help me out.
Based on my take from reviews and this forum I believe the XA25 to be more on the lean side, more transparent, than the XA30.5 or 30.8. The 30.5 having the most bloom of the three. Known to be quite distinct from the other Pass Labs or First Watt amplifiers.
Your assessment is not too far off on the XA25, yet there may be a few things to look in to further before you leap away. Also, just for grins I tried a A23+ last summer for a month. It was okay, hoped it might be a 2nd amp to rotate in to give my tube monos a rest. It was not on the same level as your XA25. You have a nice combo, worth more tuning.
Tubes: Exactly what (brand, year) tubes are in your Aric 6SN7 linestage-preamp? The sound from different 6SN7s alone can make a difference.
ICs: Seriously, what interconnects are you using between your Aric pre and the XA25 now? It's a real factor with Pass gear some times. My last 3 pairs of ICs all went to Pass Labs owners btw for similar reasons.