Thanks. The A21 is a fine amp, there are many happy owners, and I enjoyed it for three years. Plus, this is a Parasound appreciation thread ! I didn't want my finding a different amp that was a better match for my speakers to sound like I was trashing the A21. Far from the truth. Maybe you're right about driving large vs small speakers, I am not sure. Before the NS-2000's, I was driving a speaker that had two 8" woofers, but the speaker was not that high quality so not a fair test. The NS-2000's are just finicky and can be tough to match with and get right. It is well chronicled, those that don't feed them correctly lament thin bass, veiled dynamics, etc. That goes for source material too, they are unforgiving to poor source. But when matched well, they reward highly. As far as the A21+ being "significantly better" I would say it's probably an incremental improvement of a product in the same line, sure it's probably better, but there may be a little marketing (as always) at play too.... but that goes without saying.