Atma-Sphere amps and Atma-Sphere pre's are indeed an excellent match. You might consider the MP-3 with the new regulated power supply option (just recently available). Atma-Sphere amps do sound best when run in balanced mode.
The M-60's have a rather high output impedance, and so are best paired with speakers that don't dip below about 6 ohms (and not below 8 ohms would be even better). They generally work well with speakers that tend to be somewhat lean or overdamped in the bass department, which is more likely to be found among high-efficiency designs. They also work very well with original Quad 57's), despite that speaker's impedance dip at high frequencies (there's relatively little musical energy in the top octaves).
Speakers that should work well with M-60's models from include Coincident, Merlin, Omega, Classic Audio Reproductions, GedLee, Buggtussel, Cain & Cain, PHY, Lowther, Klipsch, Rethm, Avantgarde, and Pi Speakers. By no means is this list comprehensive; these are just the ones I have some familiarity with. Disclaimer - I peddle some of these speakers, as well as Atma-Sphere amps.
Duke
The M-60's have a rather high output impedance, and so are best paired with speakers that don't dip below about 6 ohms (and not below 8 ohms would be even better). They generally work well with speakers that tend to be somewhat lean or overdamped in the bass department, which is more likely to be found among high-efficiency designs. They also work very well with original Quad 57's), despite that speaker's impedance dip at high frequencies (there's relatively little musical energy in the top octaves).
Speakers that should work well with M-60's models from include Coincident, Merlin, Omega, Classic Audio Reproductions, GedLee, Buggtussel, Cain & Cain, PHY, Lowther, Klipsch, Rethm, Avantgarde, and Pi Speakers. By no means is this list comprehensive; these are just the ones I have some familiarity with. Disclaimer - I peddle some of these speakers, as well as Atma-Sphere amps.
Duke