I hooked up the A23 to the Peachtree a few days ago. I was a little disappointed that the A23 seemed lifeless and not much power. I had to crank up the volume quite a bit to make it sound even halfway decent. I just couldn't believe that it could sound this bad with the Peachtree.
Then I found out that there were level controls in the back of the A23 marked 'THX Reference'. As per the manual, I had to turn them to their maximum clockwise position. Once I did that we were back in business.
In short, the improvement is NOT subtle in any way, it's night and day. Overall, a very balanced and natural sound, with controlled and punchy base. I realized that with the Peachtree, the upper frequencies were favored at the expense of base. This is no longer the case. The A23, at least in my system, sounds amazing. One thing I really love about it is the way it handles the lower frequencies. The base doesn't necessarily sound louder than the Peachtree, but I can feel it in my chest. I'm not sure how to explain it, but it's good in a very satisfying way. Lastly, the brightness has been tamed. I listened to my music for a good 3 hours yesterday and absolutely no fatigue whatsoever.
About the only criticism I can come up with is that the amp seems to struggle a bit at higher than moderate volume. There were times when I was expecting the amp to pick up steam but it didn't, at least to the level I was expecting. Don't know, maybe there's an A21 in my future? ;)
Anyways, I was so impressed with the Parasound Halo sound that I sold my Peachtree at a very good price. A new P5 is on its way now, should be getting it sometime next week. A really cool feature that I was missing on the Peachtree is HT Bypass as well as balanced connections. I am hoping for even better synergy between the P5 and A23 compared to the Peachtree combo.
So all in all, this little experiment proved to me that not all watts are the same. Spec-wise, both the Peachtree and A23 give you 125 watts per channel. But the authority and ease with which the A23 is driving my CM10s sets them apart by a considerable distance. I can only imagine how sweet an A21 would sound in this mix.