Would switching amps make a big difference?

Al is (as always) correct about the Music Reference RM-200 having an input impedance of 30K balanced. Roger Modjeski did that for a reason, but will change that impedance to anything you want. I assume there will be a price to be paid (sonically), but I don’t know what it is. Give him a call if interested. Or get a tube pre-amp that is happy driving a 30K load.

I've owned the 11As for going on 2 years.  Currently, I'm driving them with PS Audio BHK 300 monoblocks and I simply could not be any happier.  Highly recommended! 

atmasphere,
Let me elaborate on your statement, "since solid state amps tend to double power as impedance is halved, right away you can see that the MLs will be a bit bright if the amp actually got away with that."  Actually, I think that although the SS amp has the capability of providing 2x the power as impedance is halved, the SS amp is still flat in freq response at any given moderate power demand for higher impedance.  For example, a 200 watt amp capability at 8 ohms will still output the same power across all freq below 200 watts.  I would be wrong if this SS amp only puts out 100 watts at 16 ohms, 50 watts at 32 ohms, etc.  What do SS amps usually put out at these much higher impedances?  If my numbers are correct, then for an electrostatic whose load varies from 32 ohms in the bass to a fraction of 1 ohm in the HF, the sound below 50 watts of output would be uniform across all freq, not bright.  

Ralph your link is not working! Why not just put a big resistor in series with the speaker? Say 1 or 2 ohms?

@mijostyn Don't include the parentheses at the end of the link.

A resistor will simply absorb power. The ZEROs transform the impedance so you get more power and less FR error.


@viber6  This statement is incorrect:

Actually, I think that although the SS amp has the capability of providing 2x the power as impedance is halved, the SS amp is still flat in freq response at any given moderate power demand for higher impedance.  

If the amp is behaving as a voltage source, it will double power as impedance is halved. This also means it will cut power in half as impedance is doubled. The solid state amp will only have flat response if the speaker its driving is intended to be 'Voltage driven'. ESLs are a technology that isn't based on the Voltage Paradigm (see http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php for more on that). Under the voltage rules, the impedance curve of the speaker is also effectively a map of its efficiency: peaks in the curve represent resonance, dips represent a loss of efficiency (such as at crossover points). For example if you have a woofer in a box it has a resonance in that box. To control that, the amp has to put out *less* energy (power) into that resonance, which is also seen as a peak in the impedance curve in the bass.

ESLs are not based on a driver in a box. Their impedance curve is essentially based on a capacitance. So with a typical ESL where the impedance varies over about a 10:1 range (the Martin Logans are no exception; 4 ohms in the bass and 0.5 ohms at 20KHz) you can see that to make 92 dB at 50Hz a Voltage Paradigm amplifier (voltage source) will make X amount of power; to do the same thing at 10KHz it will have to also make X amount of power, but in reality is will be about 4X the power because its voltage output is constant with respect to impedance and at 10Khz, the MLs are about 1 ohm. The only thing that prevents this from happening is that these HF impedances are so low that the speaker cable itself has a DCR that becomes significant, and a good number of solid state amps can't double power into such low impedances (IOW they are not perfect voltage sources). IMO Martin Logan is trying to make an ESL that works with solid state rather than tubes but to this end (again IMO) they are only partially successful since brightness is part of the result; inevitable when you mix transistors (Voltage Paradigm) with ESLs (Power Paradigm).