Tube Amplifier with Martin Logan Summit X


I’ve used panel speakers, mostly Magnepan and Martin Logan, for over 30 years with various amplification sources. Many years ago I owned the Martin Logan CLS’s and considered, at that time, to be the the best sounding speaker that I’d owned. With that memory in mind, a couple of years ago I had the opportunity to buy a pair of CLS2’s from a friend that I originally used with the Mark Levinson (100WPC). I was quite happy with that setup but now have an opportunity to buy my friend’s pair of Summit X’s and am looking for advice. I’ve recently exchanged the Mark Levinson for the Cary SLI80 which I’ve also enjoyed with the CLS2 speakers with bass assist from the Martin Logan Depth Subwoofer.  Now, the question. One reads so much on these forums that the electrostats, especially ML’s, need lots of power to perform well musically and that solid state is best to accommodate the low impedance loads of these panels. If I buy the Summits am I likely to experience issues because of the relatively low power output (40 W triode or 80W ultra linear) of the Cary?  I’d appreciate any advice because it’s a long drive and relatively significant expense for me. 
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I am a long-term CLS and CLX owner and have always driven them with tubes.  Purchased CLSI's and drove them with an ARC D115mkII (100 watts) in the 80's and subsequently upgraded the speakers all the way through CLSIIz's (and had Entec subs).  About 2015-16, I purchased an ARC REF110 (110 watts).  Both of these drove the CLSs well and I don't think there is a substantial difference between 80 and 110 watts. 

In 2017, I upgraded to CLXs and a REF150SE at the same time.  More power (150 watts), but I was in a smaller room at that point, so did not really need it, although I did appreciate the increase in resolution, etc.  I did add a BF 210 sub, for bass extension, not for increased output.

I think you will be fine with 80 watts, except if you want to listen concert level loud.  My bigger question is whether Summit X's are better or worse than CLSs with a depth sub (and the custom crossover file).  This is partially dependent on the status of your CLS panels.
I don’t know how many times I have been told you can’t drive ML speakers with tube amps. Thankfully I ignored that. I have had ML Quest Z’s and Summit’s that I drove with a Cary 120 followed by a pair of Cary 211AE amps. I got great sound in a 14 x 28 foot room without any issues. Before the Cary amps I used a couple of different Krell amps one stereo and the others were mono blocks. The Cary amps sounded much better to me. I just recently swapped my 211AE amps for the Cary 211FE. With the Summit X speakers you are only driving the panels not the woofers so you should be fine. 
I've had ReQuests and Summit Xs for years now. The ReQuests have been relegated to rear speakers powered by an Earthquake Cinenova amp used for all the surround speakers in my home theater setup. The amp I used and liked the best was a Rogue Audio Atlas Magnum providing 100 WPC with KT 120 tubes. I used it briefly with the ReQuests before I got the Summits, and it sounded good. I think the tubes sounded better on the Summits as it only powered the panels. 
I experimented with W4S class D and Sanders Magamp and the Rogue was more natural sounding IMHO. 
I have recently purchased a Pass Labs XA30 which makes more sense for a home theater setup. Although only 30 WPC in class A, my satisfaction has increased as I'm getting a tube like sound with SS.
To help answer your question, I wouldn't worry about your tubes with the Summit's panels. I would however, listen to the higher frequencies to determine if there is any truncating or harshness.
With my current Pass, I get a tube-like sound with a SS amp.