Class d amplification

+1 on AGD (Duets) and they are upgradable as the tech improves! I use them on DeVore Super Nines.

Before the A-S came out, I bought AGD Audions. 
The AGDs are very beautifully tube sounding but the A-S surpass them in transparency and bass. If you want to bi amp, the A-S are a very affordable way to go. 

@mglik  Correct me if Im wrong but according to your prior posts you did not have the latest "3" version of the AGD.  You had the "2".  If thats true than your comparison doesnt hold up to the current AGD model and you should be mentioning that for "transparency". .

The KEF has a sensitivity rating per speaker of 86.8 dB@2.83V/1m

a minimum impedance modulus of 3.3 Ohms at 40Hz, 150Hz so they're gonna be current hungry speakers.

so you need a high current amp that can get to sustained 80dB average SPL from your seated position (assuming 10ft from the speakers) and instantaneous transient peaks of roughly 100dB.

Plugging that into this room calculator with an amp of power delivery of 700 Watts means we get to 105.6dB at your seated position.

This is the monoblock in question - Hypex NC1200 Premium Monoblock Amplifier Apollon PNC 1200

It does 1200W into 2 Ohm, 700W into 4 Ohm and 400W into 8 ohm.

get two @digitaljoseph 

Only a two year warranty is somewhat concerning , no?