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!
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!
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.
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.
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.
Pass Aleph0s...
...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
...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
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
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
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
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
I've played the esl portion (~89dB/1W, 4 Ohm nominal, 250Hz xo) of my ML SL3 with a Zen v1 with 4 channels paralleled into stereo. Maybe the preamp didn't have enough drive, as it just didn't get loud enough, but more likely the amp wasn't powerful enough.
I'm expecting to make a single-ended Pass 30-40W for the esl portion with my Burning Amp chassis sometime soon!
I'm expecting to make a single-ended Pass 30-40W for the esl portion with my Burning Amp chassis sometime soon!
You could go all discrete and DIY something from amb
http://www.amb.org/audio/beta22/
or
http://www.amb.org/audio/beta24/
http://www.amb.org/audio/beta22/
or
http://www.amb.org/audio/beta24/
I've gotten enough feedback to determine my course of action:
I'm going to build a 15w per channel original JLH design. I got the PC boards and components to build a stereo version based on JLH's first revision of his original design published in Electronics world back in the 60's. I got a kit for $69 (uncluding shipping) on ebay. It came from Hong Kong so it took a while, but the components are first rate, and the PC board is of very good quality compared to the typical DIY custom boards. I have two identical power transformers to provide a constant +39v at 3 amps for each channel.
While this design may not be the absolute best, it should provide me with an indication how good or bad a well designed SS amp will perform with the Quads. At that point I can decide if it's worth pursuing further, or to just stick with the tubes.
It will likely be a while before it's done, but I'll post the results in this thread.
I'm going to build a 15w per channel original JLH design. I got the PC boards and components to build a stereo version based on JLH's first revision of his original design published in Electronics world back in the 60's. I got a kit for $69 (uncluding shipping) on ebay. It came from Hong Kong so it took a while, but the components are first rate, and the PC board is of very good quality compared to the typical DIY custom boards. I have two identical power transformers to provide a constant +39v at 3 amps for each channel.
While this design may not be the absolute best, it should provide me with an indication how good or bad a well designed SS amp will perform with the Quads. At that point I can decide if it's worth pursuing further, or to just stick with the tubes.
It will likely be a while before it's done, but I'll post the results in this thread.
I know what you mean by "grain" and the best sounding tube amp I've tried is a "nearly" pure triode design except that it uses a 7199 to drive a PP 7189 output stage that is triode. I've also got a modded ST70 using Kevin Kennedy's all triode design with both 7199's replaced by three 12au7s and the OPT UL taps are not used.
I've tried a lot of tube amps with these speakers and the best sounding ones for the ESL's seem to use the 6AN8 or 7199 to drive a triode output stage. The output tubes I like best are the 7199/EL84's or the 7868. My rebuilt Citation II with 6550/KT90's sound good but kind of "dry", as do the ST70 EL34's in triode mode.
Since discovering the ESL's 15 years ago I've determined that there are differences in how amps sound but the really big difference is in the speakers.
I've tried a lot of tube amps with these speakers and the best sounding ones for the ESL's seem to use the 6AN8 or 7199 to drive a triode output stage. The output tubes I like best are the 7199/EL84's or the 7868. My rebuilt Citation II with 6550/KT90's sound good but kind of "dry", as do the ST70 EL34's in triode mode.
Since discovering the ESL's 15 years ago I've determined that there are differences in how amps sound but the really big difference is in the speakers.
bear said: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
The lower power version of the Acoustat is the TNT-120.
If I recall about 60watts per.
I did a Pass Zen to drive my Carver Ribbons by parallelling
extra MOSFETs to enable it to drive the lower impedence.
I currently have several LU1014D's that I'm looking into
doing either a balanced parallelled Zen v9 variation or a
parallelled output FET Circlotron. I have Acoustat 2+2's
which are stacked electrostats, but because the do beam
highs I stuck the Carver ribbons between the panels.
The Electrostats are driven by a TNT-200.
There was a man in the small South Dakota town
where I grew up that had a scaled down HQD system
and got me started on this path. I think his system had
the 18" Hartleys and he drove his system with the small
Quad amps rather than spending on the ML amps and
the Decca ribbons are what gave me the idea of using
the Carver ribbons in my setup.
If I recall about 60watts per.
I did a Pass Zen to drive my Carver Ribbons by parallelling
extra MOSFETs to enable it to drive the lower impedence.
I currently have several LU1014D's that I'm looking into
doing either a balanced parallelled Zen v9 variation or a
parallelled output FET Circlotron. I have Acoustat 2+2's
which are stacked electrostats, but because the do beam
highs I stuck the Carver ribbons between the panels.
The Electrostats are driven by a TNT-200.
There was a man in the small South Dakota town
where I grew up that had a scaled down HQD system
and got me started on this path. I think his system had
the 18" Hartleys and he drove his system with the small
Quad amps rather than spending on the ML amps and
the Decca ribbons are what gave me the idea of using
the Carver ribbons in my setup.
Bgw
I've used multiple types of amps on my (stacked) OLD Quad ESLs.
What you need is stability at VERY LOW impedance levels (< 1 Ohm).
These speakers don't need (and can't accept) very high voltage drive.
I've used an H|H Electronic V800, a BGW 750C and a BGW 250D to
drive these speakers. The V800 and 750C are high power amps -- so
mind your volume levels lest you arc the electrostatic panels. The 250D
is a lower power amp and therefore is a safer bet if you get exuberant
with the volume level.
tim
I've used multiple types of amps on my (stacked) OLD Quad ESLs.
What you need is stability at VERY LOW impedance levels (< 1 Ohm).
These speakers don't need (and can't accept) very high voltage drive.
I've used an H|H Electronic V800, a BGW 750C and a BGW 250D to
drive these speakers. The V800 and 750C are high power amps -- so
mind your volume levels lest you arc the electrostatic panels. The 250D
is a lower power amp and therefore is a safer bet if you get exuberant
with the volume level.
tim
The 15 watts comes from the fact that about 32 volts across the input of the quad input transformer at high frequencies will arc the treble panel. This however is a bit of a simplified assumption, particularly with tube amps where the ractivity of the transformers can produce fairly high voltage spikes.
the treble panel seems to arc in the range of 3000-3500 volts depending on build variability, humidity altitude etc. The input transformer has a step-up ratio of 1:90, which is where the 32 volts comes from.
I found the zen amp to be a very good sounding amp with the quads for some reason. I had a bit of feedback in mine. It shouldn't have sounded as good as it did based on the comments above.
I tried a PASS aleph 3 on my bigger ESLs and it was not good.
I've head small Naim amps that sound really good with the quads. I'm not about to pay Naim prices for audio gear though.
The Tripath chips also can sound good on the ESLs. I'm using an AMP5 from 41Hz on a pair of 63's at the moment.
My main ESL's are still Heath W5M's on the panels and a modified Adcom 555 on the cones.
Sheldon
the treble panel seems to arc in the range of 3000-3500 volts depending on build variability, humidity altitude etc. The input transformer has a step-up ratio of 1:90, which is where the 32 volts comes from.
I found the zen amp to be a very good sounding amp with the quads for some reason. I had a bit of feedback in mine. It shouldn't have sounded as good as it did based on the comments above.
I tried a PASS aleph 3 on my bigger ESLs and it was not good.
I've head small Naim amps that sound really good with the quads. I'm not about to pay Naim prices for audio gear though.
The Tripath chips also can sound good on the ESLs. I'm using an AMP5 from 41Hz on a pair of 63's at the moment.
My main ESL's are still Heath W5M's on the panels and a modified Adcom 555 on the cones.
Sheldon
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