Although I suspect that you would have been very likely satisfied with the Parasound A21 amplifier I believe you selected the better sounding amplifier. I’m glad you weren’t swayed by those suggesting the Pass XA25 would be under powdered for your speakers. Congratulations and I’m happy for your very successful outcome. You describe the sound quality as "spectacular" that pretty much says it all. Just think about this, sound quality will improve as hours of use accumulate.
Charles
Charles