I am very close to buying a pair of Quad ESL-63's that have been upgraded by Kent McCollum of Electrostatic Solutions. Hopefully I will take delivery next Friday. I wanted to ask any owners of the ESL-63's what amplification you are using and brings out the best with these speakers? I may be willing to try SS, my preference has been using VTL 100 to 200 wpc monoblocks for the last several years on my various Acoustats. I am a big fan of the EL34 tube. I listen at comfortable levels, very seldom over 90db. The speakers will be in a room that measures 13 ft. long x 12 ft. wide x 8 ft. ceilings. I listen to everything except opera and country twang. Any opinions would be much appreciated.
Hi
Definitely a 200W amp is too big for the 63's, check the specs, they cannot handle that power (voltage in fact).
I own 57 and 63 models, although I am not currently using them.
The main problem is their impedance which has a very low minimum in high frequency, so choose an amp with good current drive capabilities.
I used Pass Aleph's and Hiraga clones with good results, that is subjective and up to you.
Just one last comment, the ESL 63 has a protection system made with zener diodes to clip the driving voltage to a safe level.
I disabled it and I choose the power amp sized not to overload them and the improvement was huge!
The other mod that I can recommend is replacing the electrolytic bipolar cap used to EQ the impedance by a film unit.
Service manuals are available on line and there are many threads here about them, too.
If you can stiffen their frame, it is also a good mod to improve them (mine came with the Arcici stands).
Good luck and you will never regret your purchase, they are fantastic good sounding speakers!
Definitely a 200W amp is too big for the 63's, check the specs, they cannot handle that power (voltage in fact).
I own 57 and 63 models, although I am not currently using them.
The main problem is their impedance which has a very low minimum in high frequency, so choose an amp with good current drive capabilities.
I used Pass Aleph's and Hiraga clones with good results, that is subjective and up to you.
Just one last comment, the ESL 63 has a protection system made with zener diodes to clip the driving voltage to a safe level.
I disabled it and I choose the power amp sized not to overload them and the improvement was huge!
The other mod that I can recommend is replacing the electrolytic bipolar cap used to EQ the impedance by a film unit.
Service manuals are available on line and there are many threads here about them, too.
If you can stiffen their frame, it is also a good mod to improve them (mine came with the Arcici stands).
Good luck and you will never regret your purchase, they are fantastic good sounding speakers!
I used a set of bridged, dual mono neurochromes with mine 222w. One doesn't have to use all the volume dial on the pre-amp, and the clamp boards arent detrimental to sound quality and add no distortion, so best leave that protection in place.
The input coupling lytics should be replaced though.
Just use any amp you like that can drive 4ohms.
The input coupling lytics should be replaced though.
Just use any amp you like that can drive 4ohms.
Using them every day with a 200W mono block Schiit Tyr power amp on each channel.
Nope, the lowest impedance is around 4 ohm @ 10 Khz.
Many modern 4 ohm dynamic speakers go much lower on much more energy intensive points in the frequency curve at a much more difficult phase angle around 45 degrees.
A very old story from the early years of SS amps that is sadly still repeated over and over again.
Not of any relevance any more with modern amps.
Last edited:
There are plenty of electrostatics around that are punishing loads. There are also a few that are more benign, and the ESL-63 is in the friendlier group.
Since anibal brought up the ESL-57 also, it's worth saying that its load was quite a bit worse, and it didn't have the delay lines to improve the phase angle at high frequencies.
http://www.quadesl.com/quad_main.shtml
While I agree that some of the worry about amp compatibility can get excessive, there are also newer amps that don't want to see a 1.8 ohm impedance anywhere. And I imagine some that don't like highly capacitive phase angles at high frequencies in particular. That tends to be the zone where issues arise.
https://www.ti.com/lit/an/slda020/slda020.pdf
"Capacitive load drive is one of the most common causes of operational amplifier stability issues. The load capacitance, CL , interacts with the open-loop output impedance of the amplifier, ZO, by adding a single or double pole in the open-loop response. The additional pole or poles degrades the circuit phase margin, resulting in transient overshoot and ringing, ac gain peaking, reduced bandwidth, and possibly full oscillations."
And the ESL-57 is far from the worst. Curves like this are pretty typical of electrostatics with minimalist interfaces:
https://www.stereophile.com/content/innersound-eros-mkiii-electrostatic-loudspeaker-measurements
"The impedance actually drops to a minimum of 0.6 ohm at 35kHz, which is probably just the series resistance of the connecting wire. Fortunately, the phase angle at this frequency is 0 degrees! Possibly the worst-case condition is at 18kHz, where the magnitude is still low at 3.2 ohms but the phase angle is -79 degrees. Musical energy is unlikely to be very high in this region, but some amplifiers will not like driving this kind of load—where the current is at its greatest when the voltage approaches zero—at any level."
Since anibal brought up the ESL-57 also, it's worth saying that its load was quite a bit worse, and it didn't have the delay lines to improve the phase angle at high frequencies.
http://www.quadesl.com/quad_main.shtml
While I agree that some of the worry about amp compatibility can get excessive, there are also newer amps that don't want to see a 1.8 ohm impedance anywhere. And I imagine some that don't like highly capacitive phase angles at high frequencies in particular. That tends to be the zone where issues arise.
https://www.ti.com/lit/an/slda020/slda020.pdf
"Capacitive load drive is one of the most common causes of operational amplifier stability issues. The load capacitance, CL , interacts with the open-loop output impedance of the amplifier, ZO, by adding a single or double pole in the open-loop response. The additional pole or poles degrades the circuit phase margin, resulting in transient overshoot and ringing, ac gain peaking, reduced bandwidth, and possibly full oscillations."
And the ESL-57 is far from the worst. Curves like this are pretty typical of electrostatics with minimalist interfaces:
https://www.stereophile.com/content/innersound-eros-mkiii-electrostatic-loudspeaker-measurements
"The impedance actually drops to a minimum of 0.6 ohm at 35kHz, which is probably just the series resistance of the connecting wire. Fortunately, the phase angle at this frequency is 0 degrees! Possibly the worst-case condition is at 18kHz, where the magnitude is still low at 3.2 ohms but the phase angle is -79 degrees. Musical energy is unlikely to be very high in this region, but some amplifiers will not like driving this kind of load—where the current is at its greatest when the voltage approaches zero—at any level."
Last edited:
When I still had ESL 63s, I used them with a DIY amplifier having an output power of two times 20 W into 8 ohm (with a clipping LED that never turned on during normal use). It was the one described on pages 140...143 of this link: https://worldradiohistory.com/UK/Wireless-World/90s/Electronics-World-1996-02-S-OCR.pdf
Last edited:
Here's some amps that I think are musically involving and a good match for the 63's. The original ESL's are a little different kettle of fish.
For an amp that sounds like nothing and is an amazing performer: Benchmark AHB2. It will bore you with the complete lack of any coloration. It will amaze you at what you used to tolerate from amplification. Best paired with their DAC3 HGC. This combo and a set of modern quads is a window into music that very few other systems can come close to. I use this daily in my shop with a set of 2805's
Next in line for sounding like nothing and transmitting your music through the 63's is a set of Hypex nCore amps. They are really what classD should be like. Makes a mockery of all the older class d amps. I typically use this with a Matrix audio mini 3 as the stream/preamp front end.
For gear that isn't transparent here's what I enjoy:
Naim Unity Atom is a good match and I really like it but runs out of steam before your speakers will. For my uses it gets plenty loud and I don't mind leaving a dB or two on the table. It's a single box solution that let me scoop out all the audio crap and regain my living space. That's huge in my book. The atom is a good sounding unit that will stream anything you throw at it. I use this daily in my main system with a set of 2912's.
For a great value and a really nice little amp: Naim Nait 5i-2 or newer. I got mine for about $600 delivered.
For tubes, I'm partial to the HK Citation 2, which is a good performing tube amp (not in the same league as the AHB2 though). I pair it with an ARC SP6a. The preamp is certainly a rose colored glasses view of the world though, but very enjoyable.
I have a Classe 70 that is a pretty solid old school AB amplifier. I used that a lot with a counterpoint tube preamp. Pretty pleasing and musical and reasonably priced. Don't use it much anymore and I guess that says something.
I've had a lot of DIY amps both tube and solid state hooked to my modern quads, the list is huge and not super relevant for you.
As was said before, the modern quads can really only use about 100w of amplifier power before you bump into the protection circuit. That doesn't mean that you can't use a higher power amp, but you won't be using all of it. There's some good reasons for doing that, especially for amps that have compromised power supplies. But be aware that the clamping circuits in the modern quads can be damaged by inadvertently putting a lot of power into the speaker. And once the clamp circuit is fried, the amp goes after the next thing downstream which is the panels themselves. So be careful if you are working with big power.
Sheldon
For an amp that sounds like nothing and is an amazing performer: Benchmark AHB2. It will bore you with the complete lack of any coloration. It will amaze you at what you used to tolerate from amplification. Best paired with their DAC3 HGC. This combo and a set of modern quads is a window into music that very few other systems can come close to. I use this daily in my shop with a set of 2805's
Next in line for sounding like nothing and transmitting your music through the 63's is a set of Hypex nCore amps. They are really what classD should be like. Makes a mockery of all the older class d amps. I typically use this with a Matrix audio mini 3 as the stream/preamp front end.
For gear that isn't transparent here's what I enjoy:
Naim Unity Atom is a good match and I really like it but runs out of steam before your speakers will. For my uses it gets plenty loud and I don't mind leaving a dB or two on the table. It's a single box solution that let me scoop out all the audio crap and regain my living space. That's huge in my book. The atom is a good sounding unit that will stream anything you throw at it. I use this daily in my main system with a set of 2912's.
For a great value and a really nice little amp: Naim Nait 5i-2 or newer. I got mine for about $600 delivered.
For tubes, I'm partial to the HK Citation 2, which is a good performing tube amp (not in the same league as the AHB2 though). I pair it with an ARC SP6a. The preamp is certainly a rose colored glasses view of the world though, but very enjoyable.
I have a Classe 70 that is a pretty solid old school AB amplifier. I used that a lot with a counterpoint tube preamp. Pretty pleasing and musical and reasonably priced. Don't use it much anymore and I guess that says something.
I've had a lot of DIY amps both tube and solid state hooked to my modern quads, the list is huge and not super relevant for you.
As was said before, the modern quads can really only use about 100w of amplifier power before you bump into the protection circuit. That doesn't mean that you can't use a higher power amp, but you won't be using all of it. There's some good reasons for doing that, especially for amps that have compromised power supplies. But be aware that the clamping circuits in the modern quads can be damaged by inadvertently putting a lot of power into the speaker. And once the clamp circuit is fried, the amp goes after the next thing downstream which is the panels themselves. So be careful if you are working with big power.
Sheldon
By the way, the reason I don't have ESL 63s anymore has nothing to do with their quality, but with a cat who liked to use them for climbing and wasn't always careful when he jumped off them. The eight cats before him never did anything like that.
I'm evaluating my direct drive amp on the '63/-989's against a Purifi 1ET400 (same designer as the nCore of course).
Can't find anything to complain about, and as you said, totally devoid of any coloration. Just the music.
DAC is an RME ADI-2 Pro Fs R. Above any reproach as well.
Jan
Hey Guys, I brought home my Quad ESL-63's today. All I can say is WOW! The transparency and coherence of these speakers is like nothing I have heard before. Super quick tight bass, Open, smooth. I am in Audio Heaven! I wanted to thank all of you who responded to my initial post. I am on the look out for a pair of the Stand and Deliver stands made for these speakers. If anyone sees a pair for sale please message me.
Great! Driving my 63s with a Quad 405 (i know.... heavily upgraded though) , works very well, and also F5 was very good despite lowish Power.
Mind you, couple of my recent vinyl purchases were low sound quality and hardly enjoyable on These speakers, they are very revealing 😀
Mind you, couple of my recent vinyl purchases were low sound quality and hardly enjoyable on These speakers, they are very revealing 😀
If you can, try bringing them out from the back wall another two feet or so.
Also try putting them up on milk crates or similar to see if you'll like the sound when they are elevated. Some people don't and it seems to be pretty room dependent. It's worth a cheap experiment before you track down those stands.
Sheldon
Also try putting them up on milk crates or similar to see if you'll like the sound when they are elevated. Some people don't and it seems to be pretty room dependent. It's worth a cheap experiment before you track down those stands.
Sheldon
I used them in a normal living room with no airconditioning and no stands and had no problem at all for 15 years, as long as no-one urinated against them or jumped off them.
Experiment with blocks and additional books to find a balance for the correct height.
MY 57 or 988,s never sounded as open anywhere near the floor in any room size.
Dont be surprised if you find the center of the panel close to ear height as the most transparent
and open sounding which on paper might not look or seem correct
MY 57 or 988,s never sounded as open anywhere near the floor in any room size.
Dont be surprised if you find the center of the panel close to ear height as the most transparent
and open sounding which on paper might not look or seem correct
I raised the speakers about 12" and they sound much more open and transparent. I appreciate the advice.