Atma-Sphere amps are wonderful and the MA-1 and MA-2 are remarkably capable of driving a broad range of speakers. The key in matching an Atma-Sphere amp to a speaker is to think about the speaker impedance curve and phase shift. To drive speakers lower minimum impedances, choose an Atma-Sphere amp with more tubes. The greater number of tubes increases the ability of the amp to deal with low impedance speakers.
The big difference between the MA-1 and the MA-2 is, surprisingly, not a matter of power output, it's a matter of being able to drive a lower impedance speaker. Sure the power output is different, but the greater number of tubes in the MA-2 allows it to drive pretty much ANY speaker whereas the MA-1 will be happier with somewhat higher and more benign impedance curves.
I use MA-2 amps to drive my Avalon Eidolon speakers that have a nominal 4 ohm impedance, but do not drop below 3.6 ohms and otherwise have a fairly smooth impedance curve. The MA-1 will just not be as comfortable with that 3.6 ohm minimum impedance.
If your Tannoys have a nominal impedance of 8 ohms or greater, and if the minimum impedance doesn't drop below 6 ohms, the M-60 will probably match well. If the nominal or minimum impedance is lower, then look to the MA-1 or MA-2, with the MA-2 being the better choice the lower/steeper the impedance curve.
Your best resource will be to call Ralph and ask him about your specific speakers. He's likely to know other A-S amp owners with your speakers and he will give you good advice you can trust.
Atma-Sphere amps are superb, and I applaud your decision to focus on finding the right Atma-Sphere amps to work in your system. Good luck!
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