Clayton M100 Monoblocks??

I am a little late in responding but I will say this amp is superb. A natural balance from top to bottom but dynamic if the material demands it. Two distinct areas of excellance is top end and midrange are consistently well balanced tonally.

Bass is very good although my speaker low frequency is limited.

A+ rating in my book.

You may consider the S-40, which should be more than enough to power any bookshelf.

I used to own the M100, to this date, I ranked it high on my top amp list. As I upgraded to ATC active 50's, I could no longer use the Clayton. Prior to Clayton, I have used ML, ARC, and other Stereophile Class A amp.

When I moved from the 200W ML to M100, I got extra bass energy, and the midrange smoothed out (almost like tube), but it has all the dynamics of the solid state.

One thing about Clayton: to my ear, most tube has more residual noise, but the residual noise seems to be a layer infront or behind the soundstage. With typical solid state, the residual noise seems to be surrounding each instruments within the sound stage. I really think this is the main difference to me. With better solid state such as M100, I almost could not hear the noise surrounding the instrument, and none of the 'noise veil' similar to tube amp as well.

The M100 is better than ATC active 50's built in amps, but elimination of crossover and speaker cables are major benefits going actives. It is a trade-off thing.

Here's an interesting review from a few years back:
http://iar-80.com/page6.html