Solid State Amps for Quad ESL 57?

The Quads will only take a limited amount of power and can be damaged by over driving. I never had any trouble as I was careful with the volume but one of my customers bought 63s and a Musical Fidelity 270 [100 Watts?] and had to have them repaired 3 times because he constantly over drove them. A big amp is fine used with care.

Never used them with the speakers, but based on Atma-sphere's comments, it is possible that the older Pass Aleph amps might work in terms of the impedance issues mentioned - they are of course very good sounding SS amps, but the matching issue may be handled by the Aleph's output into changing loads, if I rememebr correctly, they worked much like tubes in that sense.

If you really want to use a ss amp. The JC-1s little brother the A21 is much cheaper and sounds excellent on my Innersound Kayas.

Sarcher30, Innersounds are built with lower impedances in an effort to make the speaker more compatible with transistors. The Quad ESL 57 has a peak of more than 50 ohms in the bass; there simply are not a lot of transistor amplifiers that can drive a load like that with any power.

To give you an example, let's try a 200 watt SS amp, which does 400 watts into 4 ohms. Into the Quad, it will be limited to about 30 watts in the bass. OTOH, it will be able to make 500 watts at high frequencies! Its easy to see why people perceive such amplifiers as very bright and no bass when used on the ESL 57.

Atmasphere, Thanks for setting me straight. I have no experience with quads and Atmasphere's knowledge is much more complete than mine. So it looks like a tube amp is the best course.

I read somewhere that for instance if 100 wpc into 4 ohms produces 100db spl then 100 wpc into 8 ohms should produce 103 db. I think it was a car stereo book. It seemed to say that every time you half the impedance you loose 3 db of output. This seems to contradict what you are saying. Does what they are saying only apply to the voltage paradigm and not the current paradigm. I've read many of your posts about this and I still don't quite understand it all.

Thanks
Sean