I feel obligated somehow to respond to your post.
I am a recording studio engineer, having worked with many recording studios mainly in Canada and the USA (Los Angeles).
I am quite familiar with PMC speakers, both their professional and consumer hifi line. In matters of amplification, we usually look for balance of neutrality with a touch of ''humaneness'' if you permit the expression. Not to be confused with excessive warmth. By the way, for those thinking that the Yamaha is ''warm" look at your matching cables for the culprit.
In the studios where I worked, the PMC sound is very highly respected but was never described as ''lean''. They are of course neutral though.
Now about the Yamaha AS2000. I own two units. One at home, the other in the studio. This is a very misunderstood amplifier. It is also absolutely stellar about sound reproduction and mates with the PMC 22 (as well as much more expensive PMC units) very nicely. We have an inside joke where I work that whoevever priced this unit must have been thinking he was pricing a pair of cans at the time! This thing should be selling for MULTIPLES no less.
I am affraid to be absolutely in TOTAL disagreement with a previous contributor suggesting you look into Pathos, Unison, and especially Musical Fidelity - except maybe the tri-vista amp (I cannot comment on Sudgen) strickly on the basis that they are higher-caliber machines. I know this will sound absurd, but I believe that the Yamaha AS2000 is in a different, higher class as far as sound is concerned. Even higher if you include build parts quality, and features ( features set are somewhat of an afterthought for most Italian makers). I know these Yamaha's are not easy to find - I just would not beleive that many people actually have experienced them.
Not that the previously-mentioned amps are bad, they are in fact good depending or your priorities. But they do add a lot more of a ''signature" house sound to a speaker so that you will be hearing more of the amp rather than the speaker quality and source material themselves. This is not necessarily a bad thing - it is a question of taste, and if someone likes, for example, the sound of a hybrid tube-solid state Unico, well, there is a market for this. The Yamaha, at least in my opinion, is more like no-amp at all. It is VERY neutral, yet it is not ''dry'' like a Simaudio Moon or Arcam might be. Who wants to be using amps that detracts from the original signal? Well, this would include most people involved in recording - an preserving - the music's original performance.
In some studios, they are trying to replicate the sound of active PMC speakers on passive PMC speakers with a separate or integrated amplifier. For those in the know, two come to mind. A) The Bryston 4BSST amplifier. It is a do-it-all machine. And B) The old Yamaha PC2002M amplifier, long out of production from Yamaha's pro division back then. This last one was a beloved amplifier, and most units are still in daily use today in recording studios large and small. This one also did it all.
To put it bluntly, the AS2000 exceeds the legendary PC2002M in every single direction on sonic merits - and this is a feat as the Yamaha AS2000 is for audiphile use and not destined to be used in a recording studio (although you would never know it with the indestructible build quality and parts spec).
I can already predict responses to my post implying that pro sound and audiophile consumer sound are two different worlds, and they are. I cannot speak for other audio engineers, but as for me, the end result and ultimate test is always when I bring my almost-finalized client's project home. I make it spin (or stream!) on a lvery sophisticated (and quite expensive) audio system, as well as on a more modest system. I will also give it a spin in my car, believe it or not. If I don't get the ''goosebump'' factor, it's back to the audio console.
Good luck in your search, I do very strongly recommend that Yamaha AS2000 - noticing how many folks of my profession are actually being one, it is a confident buy. It least it was for me.