@cundare2 Having personal experience with both brands, as well as having the AP20 on the floor, all I can say is that T+A will have slightly better harmonics and soul. The AP20 is an exceptional unit nonetheless and satisfies those looking for a purely linear sound. I’m curious as to what doyle3433 has to say not because of comparing one amp to another, but due to the synergies of the equipment they are paired with.
With the AP20 being as linear as it is, with Shunyata cabling that I find to be a bit forward in presentation, with the SabrinaX which is very punchy in the lows and highs, the combination I heard last year could have used a little more grace and soul in the mix. Just a little bit. But I know that pairing the AP20 with speakers like the T+A Solitaire S 530 or the Vivid G3S2 and using more refined cables, I could be happy with the AP20 if I somehow had to consolidate my reference system.
The R 2500 R on the other hand, if following the characteristics of the R series, will be a bit more refined in presentation. I could see that being paired with neutral speakers like your Harbeth or my Vivids or even more treble happy speakers like the SabrinaX or Perlisten speakers and have great synergy. The Solitaire S 420 or 430 they are pairing it with has a bit more meat on the bones in terms of presentation, which together may give it an ultra refined sound in the room.
The AP20 is nearly 60lbs as well, and I’m aware you’re limiting yourself to 35-40lbs.
In short, both exceptional pieces, and synergy with speakers, power line, and cabling are key.