Any suggestions on coolest running monoblocks?

I have the latest version of the Herron M150 monos. They are terrific amps and run cool. They won't wow anyone with their looks - chassis is very plain, black and small - but they are highly musical, powerful little guys. They are solid state, but they do retain many of the virtues of tube amps. There are rave reviews at Enjoy the Music. Used about 2400-2700.

Nanotweeter,

In my system, the D-100s were more "tube-like" in the midrange than the Nuforces. Being a long time tube amp lover, this was very important to me. In addition, I felt the D-100s had a tad more width at the back of the soundstage.

To use an analogy, the difference between the D-100s and the NuForces in my system was like the difference between Vinyl and SACD. Both offer a very hi-rez presentation, but they are different. I happen to favor a more "vinyl-like" audio presentation. YMMV.

Truth is either one of these amps would be right at home in any high end system. In fact, I'm holding onto the NuForces until my new speakers (DeVore Silverback Reference) arrive, just to confirm which amp has the best synergy.

Hope this helps.

In my system, the D-100s were more "tube-like" in the midrange than the Nuforces. Being a long time tube amp lover, this was very important to me. In addition, I felt the D-100s had a tad more width at the back of the soundstage.

Due to the fact that NuForce has nearly 0 phase shift at 20Khz (compared to 15-degree or so phase shift in Hypex UCD module or Icepower), the speakers should be slightly toed-out to really focus with NuForce Ref-8. Read the latest Soundstage and Stereotimes reviews on NuForce....