[Dracule1]

I did come across a Stax f81, but price was not right.  Pretty rare those things.  I heard Beveridges in the past but never was impressed by them.  The looks are not so great either.

[Unison845]

Stax 81 can not play loud, the best amp I have driven is the Futterman OTL3, still the volume is low, much much lower then the ESL 57, so I sold it. The Beveridge model that I hear is the Model one and it sounded transparent as the Stax but louder, they image very well too.

[Dracule1]

People who heard the Stax f81 say it is the most transparent speaker they have ever heard, but like you say is very insensitive and no bass.  However, its bigger sibling f83 is a stacked version of the 81.  The f83 pair I was interested in, the guy wanted $8000 and he was in Europe. Too high a price and too much of a risk.

[Unison845]

Also these speakers are pretty old, and probably need power supply rebuild. I had to change the cap in my F81 due to leakage. F81 and F83 are pretty rare in the US. But I think the ESL57 is better balanced because it is a 3 way and have separated bass panel than other full range ESL, you can still be able to find a pair or two for stacked at reasonably cost. My stacked Quad including the stand that I build cost me less than $3000, which I considered a great buy.

[JohnR]

Also these speakers are pretty old, and probably need power supply rebuild. I had to change the cap in my F81 due to leakage. F81 and F83 are pretty rare in the US. But I think the ESL57 is better balanced because it is a 3 way and have separated bass panel than other full range ESL, you can still be able to find a pair or two for stacked at reasonably cost. My stacked Quad including the stand that I build cost me less than $3000, which I considered a great buy.

I'm not entirely convinced that stacked is better. Anyway. Did you rebuild your power supplies? One of mine seems to be gone.

[Unison845]

I prefer the stacked Quad because it excel the single in many area: Dynamic, soundstage, depth.... With a sub cross at 100Hz and extra tweeters covering 8Khz up, it transform the ESL57 into a new dimension.
Somehow I was pretty lucky, I did not have to rebuild the power supply on all 4. It is a pretty time consuming process.
Another long shot to improve the speaker is to build two direct coupled tube amplifiers for the bass/tweeter panel with active crossover to drive them directly.

[stokessd]

I prefer the stacked Quad because it excel the single in many area: Dynamic, soundstage, depth.... With a sub cross at 100Hz and extra tweeters covering 8Khz up, it transform the ESL57 into a new dimension.
Somehow I was pretty lucky, I did not have to rebuild the power supply on all 4. It is a pretty time consuming process.
Another long shot to improve the speaker is to build two direct coupled tube amplifiers for the bass/tweeter panel with active crossover to drive them directly.

When going to all that trouble to change the 57's into something it wasn't designed to be, why don't you just build the ESL's you want from scratch?  Building one from scratch has got to be easier (it was for me).


Sheldon

[Unison845]

For me, the chance to build an ESL with Quad sonic signature is very slim, that's why I took this route. I am very happy with how it turned out.

[airhead]

Follow up about the Stax's:  I have an old pair of Stax F83's, driven (like Union845's) by Futterman OTL3's.  I can easily get 95 db out of them, but usually listen at lower levels, since the amount of detail and information one gets is so wonderful at lower levels.  I had mine reconditions by Electrostatic Solutions.  There are many problems with these speakers, unfortunately:  for example, a resistor in the RC network is way underspec'ed and hence prone to failure, messing up the bass performance and leaving the panels vulnerable.  I have recently added some of Roger Modjeski's subwoofers for bass below 100 hz which helps a lot.

[Unison845]

Here is the Stacked Quad with the OB subwoofer behind crossed at 80Hz. Driven by a 300B PSE (15W), the stacked Quad can play them safely loud.