Short List of Amps I prefer over the Pass Labs XA25 or INT 25


I am anxious to see what comes.

If your response includes the word "But" please restrain yourself.
chorus
Audioguy-Re the Sugden idea. I had the Masterclass IA 4 in the system last week as a test thinking it should be pretty good. Oddly it did nothing special for the sound. I was surprised. Just not a great match for some reason.
Cal- Re the First Watt F4s Monoblocks. I wonder if these worked best with your speakers as your speakers are a harder to drive and the F4s have more power than the XA25?
A 20 year old amp that I prefer over all First Watts and XA25 (which is a souped up FW) is the Plinius SA50 Mk3.  
@atmasphere,  interesting and beautiful theory /hypothesis on harmonic orders. it is not easy to imagine how it works in practice. how different harmonic orders are related in phase/time, why their combination should lead to a soft pleasing sound? how many amps with 0 distortion did you see, what you mean when you refer to an amp without any distortion? and what if the distortion is too small, say .001? would then still a several harmonic order sound with distortion be better, by the way, how many harmonic orders give tube amps (all of them the same number)? 

i was a tube fun for 15 year used only tube amps. once i tried a class ab/a amp i was indeed pleased and even released with a clean clear sound that it produced. if your auditioning experience is based on  a sound with distortion, you are merely in a wrong musical world. it is a personal matter whether you like it or not. in painting, i personally like impressionism the most, because i like to see the world in this alternative way. but ii think sound and music is something different, one naturally prefers a natural uncolored sound that come from musical instruments. if there is a luck of some details and sound is not clean,  you do not really perceive what the artists wished to express. 

 i personally do not like colored sound that produce many expensive and extremely expensive amps (and also speakers). they just to not sound right for me. currently, i am pleased with Cherry Megaschino class D amp which sounds very neutral, detailed and clean, is much smaller and consumes much less energy.