Sound Lab vs Magnepan 20.7

True Ralph, but most serious junkies use a specific amp with a specific speaker anyway. Change one and you most likely will have to change the other. When an engineer designs a speaker/amplifier combination, he can tailor each to the other.

Ralph, yes there is a benefit in transparancy with the OTLs that I have realized but now I am putting that signal through a transformer with my Quad 57s. Previously that was not the case with my Jazz Modules. I was hoping someone could talk more about the use of a direct drive amp. I know Roger Modjeski builds one and some Acoustat users have modified their speakers to use it. But can it be done with other ESL designs such as Quad or Soundlab? At what level of complexity or risk. You pointed out a couple in your post but would like to hear more from you and others. Perhaps I should start a separate thread on that.

Acoustat actually made a powered direct-drive ESL. They had to integrate the amp into the speaker on account of the rather dangerous high voltages involved.

This will be the case with any direct-drive installation. Of course, any ESL can be direct-driven if you are willing to do the surgery. So it would be possible to do that with a Sound Lab. But with the voltages involved to bias the speaker, the amp would have some very high operating voltages which would make it a challenging amplifier to build and operate.

Clio, Modjeski is very familiar with the 57's, and makes custom amps. Give him a call (he's up in Oakland/Berkeley now, not Santa Barbara), and see what he says about making you a direct-drive OTL for your 57's. Then let us know what he says---I have a pair of 57's too!

I used to live in Santa Barbara and visited with Roger back then. I was with him and Kavi Alexander once listening to an early version of his ESLs powered by an RM-200. I am now moving to the Bay Area and will definitely look him up. From what he mentioned to me the RM-10 which is one of two amps of his that I have was designed with the 57s in mind.

Quite frankly I am entirely pleased with the Atma-Sphere M-60s powering both of my speakers. The direct drive idea was more out of curiosity. I am sure Roger will satisfy that curiosity.