Best solid state amp for stacked ESL57's

[kkillebrew]

I've never connected my ESL57's, stacked or singularly, to any solid state amp - been afraid to - all I have is a Denon AVR3805 and I'm afraid of someone blowing away my fragile and delicate beauties with that big digital iron.

For the ESL57s, I have always used my Quad II Monoblocks or a certain incredible 7189 based kit amp (LK48) made in the 60's by HH Scott. These, so far, are the best and most musical amps I've heard with the Quads.

Now I have this itch to build a solid state amp that is suitable for the stacked ESL's, both in signal and quality. I only need about 10 to 15 watts/channel of the finest amplification silicon can provide.

Is that the Pass Zen? Or Something else? Sheldon Stokes has recommended the Zen for ESLs an that carries a lot of weight for me.

I'd like to hear suggestions from those who've done this or heard a good SS amp that matches well with the Quads. Something that I can build and that others have built. Thanks!

[cyclotronguy]

Nelson Pass used to be a fan of stacked Dayton Wrights..

Cyclotronguy

[arend-jan]

Building will probably (?) mean chip amps. Tripath chips are a popular solution or a Hypex class D chip which are highly regarded. For a stacked pair I'd build two amplifiers so each speaker has it's own channel.

A common misconception is that the Quad ESL performs best with a 15 Watt amplifier. Believe it, a little more power will do wonders for the dynamics and bass of this very nice speaker. I had very good results with a single ended GM70 amplifier (about 35 Watts). If the speaker is up to specifications then you are not likely to blow it up, unless you have a hearing problem. If you are worried about arcing the treble panel, get a clamp board and install it.

I'm interested to hear about the results when you build something.

[arend-jan]

Additional, I looked at the pass Zen and I don't think it's suitable because (according to it's documentation) it does not like impedances below 8 Ohm (a single Quad ESL drops to about 2 Ohm in the high frequencies, so this will give a rather rolled off sound) and IMO it should have a little more power than 10 Watts.

[marin.weigel]

...and stacked Quad ESL57s didn't mate well as I tried that combination years ago.
This amp actually shouldn't have problems with the impedance curve of two paralleled 57s per side, but I had the impression that the always present offset at the output - no servo here! - did saturate the audio xformer and somehow hardened the sound. Tweaking the offset helped just for a while, because it wouldn't stay at zero.
So my experience is, that just about any amp design with considerable output offset will be problematic.
With my Magnepan Tympani4As this amp was simply the best I had tried.

Regards, Marin

[kkillebrew]

So no Zen... what about the JLH? or other DIY suggestions? No chip amps, quality over power, I just need 15 to 20 solid watts per channel.

[tubesguy]

If you want to try old-school, the classic answer is the Levinson ML-2. I think someone here (GR?) did a DIY version some time ago. Just add some Hartley 24" woofs and Decca ribbons, and you're good to go. - Pat

[bear]

Over in the Soylent State section there have been quite a few threads on Class A amps... suggest you check them out.

Just thinking out loud, and for no particular reason, I think I would want a Mosfet output, JFET input, and fully complementary (if I could get it) front end design.

Nothing preventing you from dropping the rail voltage on a higher power class A design too... for lower power.

The obvious candidates include the Pass designs, Borbely designs, JLH designs, Leach designs, and those that also use Hawksford/Cordell error cancelling... Let's not forget the Strickland "Hafler/Transnova" circuit biased for class A with lower rail voltages too... (an interesting choice for ESLs, btw).

Maybe try one of each?

_-_-bear

[tc-60guy]

Hello kkillebrew, How about a pair of used Adcom gfa 5500 amps? Cheap and decent.

[bear]

ick... sorry just my opinion.

the esls will reveal any "grain" at all...

truthfully, the best thing you can do with those esl speakers is to build up a sophisticated pure triode tube amp of the requisite power. Some 845s or 211s or similar tubes will do that trick nicely.

Another road that might yield a good listening experience is to clone an Acoustat TNT 200 but use a lower rail voltage to keep the max power under the max for the two quads - quads are known to fry through the drivers due to overpower/clipping.

Actually you could build the TNT200 at the full rail, but use way bigger heatsinks and bias it way up into Class A, yielding a very powerful 50 watt amp...

Check out the schematic... it's around. Maybe even quoted in this forum.

_-_-bear