Best amp for Martin Logan Summit X

Hi Rustler. I have a pair of ESL-11A's and have been running an ARC Ref 75 amp. After a lot of investigation I have realized that I am not getting all that I can from these great speakers. At a 4 ohm rating, like yours, they need more current to  make the top end sing. I am awaiting delivery of a Luxman L509X that mates exceptionally well with these. Good luck.

I paired mine with a D’Agostino Classic Stereo and it was a very good match.

Excuse me if you already know this, but what people are talking about is that when the impedance of a speaker drops it becomes harder for an amp to drive it properly. Summit Xs drop to an impedance of less than 1 ohm at 20khz. That’s about as low as you can go and, in general, Martin Logans are just a hard speaker to drive properly. What you want ideally is an amp that doubles its output when you halve the impedance it is driving. 200 watts into 8 ohms, 400 watts into 4 ohms, 800 watts into 2 ohms.

But, there isn’t a lot of music at 20khz and most of us can’t hear it if there is, so it’s not absolutely necessary to have an amp that doubles down to 2 ohms or 1 ohm, but the Summit Xs do benefit from a good stout amp and you can get a good one in your price range. There are other aspects of an amp besides doubling down that you want to consider, of course, and you may prefer an amp that doesn’t double down to 2 ohms but just sounds better to you because of a really good midrange, for example.

Let me know if you have any questions for me about my experience with the Summit Xs or the D’Agostino.

Thanks for the very helpful input, Tom.

How about Simaudio products, say 600i with Martin Logan higher range, say, Expression ESL 13A? 

That would probably work, gorchkov.  If your room is large or you listen loud, you may strain it a little.  MLs like power.  See my explanation above.