Solid State Amps for Quad ESL 57?

ct0517                    1-11-17

" When discussing the Speakers with the Amp manufacturer, and he/she can’t answer directly with facts, and says.

"Oh, don’t worry your speakers won’t hurt our AMP"

Then it’s not the right amplification for these Quads "

Soon after I purchased my first pair of quads I asked a Technician who was building amps on his dining table whether his amp would damage my Quads and he replied. " No, my amps are kind to loudspeakers." I was so impressed with his reply that we became good friends but I never tried his amp on my Quads.
 

I ran Decca ribbons with my Quads and a small sub back in the early-mid '80s- could never get the thing to cohere completely, but as my late audio friend, Chuck Lamonica said, "You could kiss every note." 
I still have the Deccas--also in need of a restoration, but lower on my list. (I used Sequerra ribbons at one point too, and was able to talk to Dick S. to get replacement ribbons from him. He was very kind).
The history behind this stuff is fascinating, as is the ability of equipment now 60+ years old to deliver a level of quality that in some ways, has not been duplicated. 

@ct0517  +1

It's a bit tricky alright. Of course, you could put an air core inductor between the amp and the speaker to compensate, but that's tricky because it risks electronic resonances. Actually, it's quite unwise to attempt this unless you've made your own equipment to be bullet-proof.

The alternative is to compensate upstream, at the preamp or the cartridge step-up transformer. The obvious thing is to increase the capacitance of the 75uS RIAA compensation, starting by say doubling capacitance. Let your taste be your guide.

I should add, the Quad 2905's come properly compensated for solid state right out of the box. The 2805's less so. Re-working compensation for the 2905's is only necessary if you mess with the electronics.