What amp for the Revel M20

Well if the Revels are like other small speakers the increased need for power and volume, has nothing to do with your speaker, but instead your ears. As you turn the juice up, the speakers bass allignment changes, and provides a few hertz better extension. As such, the speaker starts to sound more full bodied. There are two ways to approach this: Frist, by a big amp a listen at louder volumes. Or second, if you plan on keeping the tube amp then buy a good sub. You can listen at softer levels and still have a full sounding system.
Best,

Revel/Mark Levinson #383. Also new McIntosh. Peace and Good Listening, Pat.

I have just brought some M20's which have replaced the excellent, but flawed Triangle Celius (despite 91db sens. drop to 2ohms in the key upper mid band, so need juice!).
However, my CJ MV60(55W) is not really man enough for the M20's, so I brought a Carver(250W) pre/pow combo from the very excellent Underwood HiFi, at a close out price and it performs with the 20's extremely well. I am keeping the CJ to drive a pair of rebuilt Quad Esl 57's, as it has a 16 ohm tap.
Anyway to cut a long story short, I agree with warrenh, they need a lot of juice! at least a 100W.
Happy listing!