Amp for Martin logan CLS Originals

If you are brave you could try the NYAL OTL3 that is for sale now.
I bought Stax F83's years ago (in the eighties) and tried many many amps before settling on this one. Head and shoulders above everything else I tried, including Counterpoint, Audio Research, and several solid state amps.
The tubes for these are no longer available, but the seller is including a new spare set, and they seem to last forever. Of course, the Stax's have an even higher impedance that the Logans, so it may not be quite such a dramatic difference.

The tube suggestions make all the sense in the world, but curiously enough way back when, ML used Thresholds for shows and Threshold used ML's amongst others when developing their amps. Go figure?

Unsound, ML used ss amps for shows in order to insure good solid controlled bass. However this meant forfeiting the incredible silky highs and delicate, lifelike mid-range of which almost all stats are capable when driven by tubes. The alternative would have been for ML to drive all their hybrid models bi-amped -- which I bet they rejected fearing it would turn off a lot of customers because of the cost(s) they'd incur.

However, the CLS's, the original Statement, and the CLX are ONLY stats -- no cone woofers! So there is absolutely no reason IMO to drive them with ss amps; none! And if required, the lowest two octaves can be provided by a ss-driven sub.
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Celtic66 is dead on accurate. I owned CLSiiz's and used a vast variety of SS amps, namely Plinius SA250, BAT VK500, Pass Aleph 2 monos, but the best overall performance I experienced was after mating the CLS's to a pair of Manley Ref 450 mono's, that I of course acquired used. Those speakers came alive and sang with joy from power o' plenty!

The CLS 1 (the original) had a high impedance and was a match made in heaven for tubes, even OTLs.

The CLS 2 was an example of Martin-Logan's attempts to make ESLs compatible with transistors. It was very low impedance, 0.5 ohms at 20KHz. Almost any amplifier sounds better on it if using a set of ZEROs to help with the impedance.

The CLS Z and later models do show some moderation with regards to impedance, but still are built to favor transistors.

Its hard to make transistors sound right on a full-range ESL due to the impedance curve. There is a tendency to be weak in the bass and too bright in the highs. As a result many ML owners place the speaker fairly close to the rear wall to try to get back some of the bass, but it is often one-note bass due to the placement (ESLs need to be out in the room at least 5 feet).

But the CLS 1 (which, BTW, it sounds like ML still has parts on hand to build them) is an easy load for most amps and IMO the best of the lot; of course I have a bias :)