Solid State Amps for Quad ESL 57?

Hi Ralph, So the box resonance is what makes the voltage paradigm work. Without the box the current paradigm is the way to go. So I assume open baffle designs and horn designs would need the current paradigm also if their impedance curve is not flat. That makes sense and would explain why alot of people perfer tube amps for these type of speakers. Thanks for taking the time to explain.

Dhcod
Try a Quad 303, updated and modded by one of the pros.

Mrtennis, the only way I've seen proper bass out of Quads with transistors was when the panel was too close to the rear wall.
At the same time the highs were dreadful- harsh and lacking real speed. I have trouble believing something like that could be termed 'accurate'.

I use a rebuilt and updated 405. The only mod i did was replace the TLO71 with an opa227p (not just a drop-in replacement) and lower the sensitivity so it mated better with my Modulus 2A.
Magic for about $300!

I got reasonably good results with a Bedini 25/25 but would probably use tube amplification today.