Will a pair of Manley tube amps be a good match for Martin Logan ESL 11A's?

@mijostyn, I’m not sure of the year Strickland and Beveridge each introduced their direct-drive ESL (the first Beveridge ESL, the Model 1, was invented in 1965), but I do know Strickland discontinued his amp and went with a transformer because of reliability problems in the amp. Modjeski says he has repaired a few of them, and found it’s design weaknesses, designing a mod to correct them. One of his services is to rebuild the Acoustat amp, for which owners send him their broken ones. Roger was hired by Beveridge to solve the reliability problem in his direct-drive amp.

Roger worked in an electronic repair shop in high school, and learned how NOT to build an amp. If a circuit calls for a 2w resistor, he uses a 20w. Trouble-free operation is a very high priority for him, in contrast to some more widely-owned high end brands who put other priorities first. When I bought my first ARC electronics, turning on the SP-3 pre-amp for the first time blew a resistor. I couldn't believe it. My dealer (Walter Davies, who co-developed his patented Last Record Care Preservative---which is NOT Freon ;-) put it on his workbench and had it up and running in a coupla minutes). That was a long time ago, and Bill Johnson did eventually learn the lesson he should have known long before (he too started his career as a repair technician). At a seminar I attended in the 1990's, Johnson talked about how a batch of bad parts almost put ARC out of business in the 1980’s.

The following may appear to contradict what I said about Modjeski's opinion of OTL's paired with ESL's: Roger is making his own ESL loudspeaker (which includes an 8" woofer for each side; another pair can be added, of course). But dig this: he is also offering it with a direct-drive OTL amp for extra $. "Direct-drive"? The mono OTL for each speaker has no output transformer, of course, but the ESL has no input transformer. The OTL output tubes drive the ESL panels directly!

Modjeski worked for Harold Beveridge, who had Roger redesign the power amps that were integral to his ESL, also direct-drive. So this is not new to Roger, but it sure is unique. It takes a lot of engineering knowhow to pull off, involving the disciplines of power amps, tubes, transformers, ESL design and construction, and extremely high (lethal) voltages. No kids or pets allowed in the room ;-) .

@georgehifi has given you a good lead in the Music Reference RM-200 Mk.2. It is the only tube power amp I know of that puts out 100 watts at both 8 ohms and 4 ohms (do the McIntosh amps also?). The common wisdom used to be that OTL amps were a great match for ESL’s, and the Futterman amps were often paired with old Quads, single and stacked. Lots of Atma-Sphere amps on Quads and SoundLabs as well.

MR’s Roger Modjeski, a very opinionated designer/builder, disagrees (and has no axe to grind; he builds OTL’s himself). If interested, go to the MR website for more details, and read Michael Fremer’s review of both the original and Mk.2 versions of the amp in Stereophile (and equally important, John Atkinson’s bench test reports).