@andy_wonderwall You've gotten good advice here. Martin Logans are traditionally hard to drive for any tube amp due to the 0.5 Ohm impedance at high frequencies- so an amp like the M-60 will sound muffled. You can fix this by using a set of ZEROs http://www.zeroimpedance.com
-which will be helpful with most tube amps on that speaker. MLs are designed to try to take advantage of the solid state market; the problem is the ESLs in general don't behave the way the usual driver in a box does. ML tries to get around this 'problem' (which normally is solved by a tube amplifier) by making their speakers very low impedance. This prevents the usual doubling of amplifier power that a solid state amp might otherwise do. It also means that speaker cables are critical to the sound; how 'open' the speakers are.
Other than the ZEROs, your other solutions are obviously a different amplifier, or a different set of ESLs that are not so low impedance. For example M-60s work quite well on ESL57s or ESL63s made by Quad (and several of the newer Quads too).
We do have customers using MLs, some for decades on now. All of them use the ZEROs.