Tubes and less sensitive speakers

Also to answer the OP's original question, Audio Research and Magenpan have have had a nice love affair going on for some time now, so perhaps look into their amps.

I agree that with Ralph that if you're using the 3.7's and want to look at Atma-Sphere, look into the MA-1 and not any of the smaller models. I've been in the camp of trying to mate his smaller amps with autoformers on larger planars / stats and while it's pleasant, you won't get the best out of them. The MA-1 MK3.3 is highly recommended as long as you can handle the number and heat of the tubes.

Thanks for all the info and opinions.  I admit I have a case of upgradei itis and am approaching this with caution.  I am also considering Magnepan's new X models from which I have heard very good reports.

The Music Reference RM-200 MkII might make for a nice amplifier choice for Maggies as @bdp24 noted. One of the reasons is that it is one of the few if not only amplifiers with a tube output stage that outputs more power into lower impedance loads. As measured by Roger Modjeski on his bench the amp puts out 112 watts into 8 ohms, 145 watts into 4 ohms, and 125 watts into 2 ohms.

Regarding the poet by @blisshifi: Mating subs with Maggies (in fact any and all dipole loudspeakers) is indeed a challenge. The solution is a dipole subwoofer, which Magnepan has been working on a for a few years now.

There is already a real good one available, the Rythmik Audio/GR Research Open Baffle Servo-Feedback Subwoofer. It employs two or three (your choice) 12" servo-feedback-controlled 12" woofers in an open baffle frame, and works splendidly with dipole loudspeakers. Check the GR Research website for details.

I have no personal experience with the Sanders Magtech amps (other than reputation), but they are manufactured by CODA, and that is never a bad scenario