About 10 years ago I talked to Quad about the right size amp for my ESL 63s, at the time I was using a Quad 303. They said that if I used a more powerful amp I may notice a difference on the attacks of notes, the start of the note. I duly upgraded to a quad 520 and it made a difference though I’m not sure it improved things. Now I’ve learned that I prefer the sweet sounding 303 to the 520, though I’m not using either with the quads.
At at the moment I use an Electrocompaniet ECI - 2 with the ESLs (they are with Gradients, so I guess that means that the Electrocompaniet has less work to do) The setup sounds very good . . . but not good enough. It has presence, with a big 3D image, but the image isn’t as firm and airy as in the Spendor/Krell system, which captures more of the details of voice and instrument separation and placement.
Like Bencat I have a Mk1 Krell KSA50, which I’ve been assured delivers about 75W per Chanel Class A. This sounds fabulous in a system with Spendor SP 1s, better than the Quad system for imaging. I intend to swap the amps soon (it weighs 30kg, so to lift the Krell around is a pain!),
No preamp in all cases; volume control digital through the Logitech Media Server; Theta and Museatex DAC with Spendors and ESLs respectively,