stewart0722,
The Magnepan 2.5R are 84db (the 3.7 are 86db and the 2.7 are 87db).. I would consider all of these as inefficient speakers but not sufficiently so to rule out the use of the 60 watt Vac Avatar as long as the room isn't too large and the volume ismoderate. The speaker's 4 ohm impedance may be a bigger issue, however, the VAC does have 4 ohm speaker taps. I don't think we know enough about natureboy's room, budget or listening habits to rule out the use of his VAC.
I think your suggestion of the Emerald Physics 100.2, (currently on sale for $599) may be a good match for the 2.5s. I own a 100.2SE(150 watts/ch @ 4 ohms) and use it in bridged mode(450 watts@ 4 ohms) for my CC3 center channel. When I first received it I tried it out in stereo mode on my 2.7s (just out of curiosity) and it drove them very well; very good bass, very dynamic,dead quiet and finely detailed with a very sweet and smooth mid-range and treble. It uses an analog power supply(not a switch mode power supply) and the amp is stable down to 2 ohms. Of the 3 brands of class D amps I own, I think the Emerald Physics has the most tube-like mid-range and treble while still possessing the typical class D excellent bass response.
While I think this amp in stereo would perform very well driving Natureboy's 2.5s with its 100 watts/ch, I think buying 2 and bridging both to mono for 250 watts/ch is likely to give natureboy the best performance from his 2.5s, well worth the added expense.
Tim
