1994
Let’s talk about the Quad ESL57. I don’t recall the exact year, perhaps around 1994, when I first encountered the legendary Quad ESL57. This was in a day before the internet had infiltrated all our homes. At the time I was living in the little village of Norden, in Rochdale, Lancashire, back in the United Kingdom, and information on anything related to this old Quad electrostatic could be found via old print publications only.
My system at the time was built around a Linn LP12, a Cambridge Audio CD2 CD player, amplification from Linn (LK1/LK2), and a very nice pair of Sonus Faber Electa speakers (and later, QLN Signature Splitfield II). Perhaps a year or so prior to encountering the 57s I was tooling around a junk sale and came across a couple of interesting items that I snagged for around 50 quid. The pair consisted of a vintage Leak Varislope preamplifier and a matching Leak Stereo 20 valve amp. The Varislope looked brand new, was in its original carton, complete with all paperwork, and sounded, well….pretty horrible. The Stereo 20 amp had some signs of wear but worked beautifully. Mated with the Sonus Faber Electa, the Leak Stereo 20 brought some of the finest sound quality I’d heard up to that point, into my home. Vocals were incredibly dense and rich, brass instruments sounded real, everything had warmth and body and a presence that made music such a pleasure to listen to. This was well before the day that audiophile neurosis had completely taken over my psyche. I was actually just in it for the music back then, I wasn’t chasing the last nth of detail or some unobtainium ‘live sound in your home’ that I became obsessed with in later years.
I was using a pair of Linn LK2-75 power amps at the time, to drive the Sonus Fabers, and I’d pretty much determined that two amps didn’t sound any better than one, so I decided to sell off one of the amps. I can’t even recall where I placed the ad. There wasn’t a Craigslist or even an Internet that I had access to at the time, so I probably placed an ad in the local paper, unlikely as that seems. I got a call from a fellow who wanted the amp but wanted to offer up something in part exchange. He’d a few things available so he suggested I come along to his home to take a look. The first thing of interest I saw was a pair of KEF 104/2 speakers, nestled in the corners of his room with a large fireplace extending into the room between the two speakers. I had a quick listen to the KEFs and decided that I’d never heard a more natural-sounding and better imaging speaker in my life. They sounded fantastic, but he wanted my amp plus an amount of cash that I didn’t have. We poked around in his listening room looking at this and that but nothing was really standing out, so he took me into another part of the house and showed me a pair of stored Quad ESL57 speakers. The Quads looked original and in good condition but he wasn’t able/willing to hook them up, so I took a chance on them and we exchanged Linn LK2-75 for Quad ESL57.
Getting the speakers home, it was quickly established that these things weren’t going to be allowed in the living room, where I had my main system set up. The only other available room was a spare bedroom which was not much bigger than the typical walk-in closet you’d find in an American home today. Perhaps 8’x8′ at the most. And that’s where they lived for the next couple of years, hooked up to the Leak Stereo 20 amp and the Varislope preamp, with an old CD player and an old FM tuner used as sources.
Thinking back I recall being fairly enamored with some of what the Quads could do in this small room, but they were very much second choice to the main system with the Sonus Faber. Listening to the Quads in that small space it was necessary to sit on the floor with my back against the door and the speakers perhaps four or five feet distant. There wasn’t much low bass to speak of, but the midrange was pretty incredible. They really did provide a transparent window into the recording space and there was something really special in the way they reproduced anything small in scale, and in particular, anything acoustic and unamplified. There was certainly a synergy with the old Leak valve amp, it imbued some needed warmth and body on instruments, fleshing out the images in a way that the Linn LK2 could not do.
1997
The speakers remained in my possession for perhaps two or three years, until an opportunity arose for me to move to the USA on a 6-month work assignment. Eventually, the move became permanent, and I returned to the UK for a couple of weeks to clear out my home of all the worldly possessions that couldn’t be transported economically with me across the pond. Out on the curb for the garbage collector went the vast majority of my vinyl collection, and an old pair of Quad ESL57 loudspeakers.
2019
I waited over twenty years for my next encounter with the Quad ESL57. This time it was at the 2019 Capital Audio Fest, in MD. I landed in the demo room of Robyatt Audio to see the wonderfully restored Quads sitting there winking at me. I hadn’t heard of Robyatt Audio prior to the show so I was keen to learn what this fellow, a Brit as it happens, was all about. It seems he’s a dealer for several high-end brands and that he represented a Quad resto company, Electrostatic Solutions [visit Electrostatic Solutions’ website here].
I wrote a brief report on Robyatt Audio on returning home from CAF2019, and you can read the show report and my experience with the restored Quad ESL57 here. My conclusion after a half hour or so in the Robyatt Audio room is summarized in this paragraph taken from my CAF 2019 review:
“I know the Quad sound pretty well, even though it’s been over twenty years since I had the misfortune of having to place my 57’s curb-side for the garbage collector. I would never have described the Quad-sound as veiled, even sitting off-axis, but that’s what I heard. Pleasant enough but lacking in dynamics and soul. Since others have indicated a more pleasurable experience, I’ll give Robyatt [Audio] the benefit of the doubt and try to catch them at a future show.”
There’s nothing much else to be said about what I heard at the show. In writing this (February 2022), I visited Mr. Wyatt’s website at the link above and no longer see mention of Quad or any affiliation with Electrostatic Solutions, so perhaps his involvement was a fleeting one. Still, my memory of the classic Quad 57 was somewhat diminished by the experience of hearing them at CAF2019 courtesy of Robyatt Audio.
2021
Much has changed since the early days of owning the Quads, almost a quarter-century ago. A LOT of gear has passed through my system in the intervening years and I’m cognizant of the fact that somewhere along the way the emphasis shifted a little from enjoying music to enjoying gear. One of my pastimes has become the relentless search for new stuff to play with, new gear to bring into the system, and to that end, I spend an hour each day scouring through various classified ads, including my local Craigslist. And so my eyebrows raised one fine summer’s day in 2021 when I spotted an ad for a ‘nice pair of Quad ESL57s’ just a couple hours Northwest of me. Let’s take a look at what I found –
As you can see from the above, this particular pair was in close to mint condition – unrestored, unmolested, cared for, and with my name written all over them.
The dog knows; if only he could speak…
I spent a happy month or two with my new toys and I believe that I finally got to hear the Quads how they were meant to sound; in a high-quality, well-curated audio system. My old Quads never really got to play with the big boys. The Leak Varislope preamp I used back then was horribly veiled, I’m sure it needed a complete recap and restoration. And though I also used my Linn LK1 preamp, even the Linn wasn’t really up to the task of letting the music flow unfettered through the wonderful Quads.
In my 2021 system, I was fortunate enough to use some quality gear and to hear just how special the 57s really are, even by today’s standards of audio reproduction. As you can see in the photo above, my front-end was primarily vinyl – the excellent Origin Live Resolution MKIV and Illustrious tonearm, a Manley Labs Steelhead phonostage, the incredibly transparent Emotive Audio Epifania linestage, and my trusted Thor Audio TPA-60 monoblocks.
Sound of The Quad ESL57 Speakers
I’m sure you’ve all read about the main qualities of the ESL57, the incredibly open and transparent window to the recording space – and its midrange. It’s one thing to read about it, and you can try to use some point of reference from your own system to understand what’s meant by the term ‘transparency’, but you really don’t know what’s possible until you actually get to hear the 57s properly set up and in a good system. There’s literally nothing else like them, and given their age, that’s quite a remarkable statement in itself. The closest I’ve heard any other speaker come to capturing the transparency of the Quads was with a set of early Martin Logan CLS. But even they were off the mark in ultimate terms. I could waffle on a bit here about what the term ‘transparency’ actually means and why it’s so difficult for a conventional loudspeaker to remove itself from the sonic landscape. But it’s easier for you to just think about the term in a literal sense, and imagine that you’re in the room where the recording is happening and there are no mics, nothing electronic capturing the sound, it’s just you and whoever is singing or playing instruments on a stage. Other lesser speakers (and most, if not all speakers are ‘lesser’ when compared to the Quads in the realm of transparency) place you there but there’s always a sense of opaqueness, always some small filter that comes between your ears and the sounds being made.
And It Isn’t Just Transparency That The Quad ESL 57 Does Well
It’s relatively easy to describe transparency, but it isn’t so easy to put into words the sense of microdynamics that the electrostatic panels in the 57 are able to produce. Transients in the microdomain appear from the speaker almost instantaneously, with notes starting, blooming, decaying, then stopping effortlessly on a dime. Listening to well-recorded acoustic music, the Quads can present sounds with an ethereal quality the likes of which most of us have never heard. It’s certainly safe to say that I’ve never heard microdynamics, coupled with this level of sheer open transparency, from ANY box speaker, at any price. And I’ll extend that into the realm of other electrostatic speakers I’ve heard over the years and other conventional dipole designs. Take something like the Spatial Audio X3 that I recently owned and reviewed. In comparison to the 57s, the Spatial X3 was dark, slow, colored, and lacking in inner detail. Sure, their macro dynamic capability was far beyond that of the 57s, in fact, the 57s would have been reduced to ash had I put them through what the Spatial X3 went through in my listening room.
Another aspect of the 57s performance that is difficult to express in written form is the way in which they image. If you get the speakers well away from room boundaries, at least 48″ from the front wall, then tuck your listening chair quite close to the speakers, perhaps within 6 feet or so, and the speakers around 6 feet apart on center, with around 15-20 degrees of toe-in, there’s a chance that you’ll hear imaging unlike anything you’ve heard before. Of course, it’s a function of what you’re feeding into the Quads, but feed them from a good source, with a neutral and transparent preamp, and give them a handful of quality tube watts from a good power amp(s), and you’ll literally have the performers right there in the room with you. (I’m not talking about the unnatural, hyper-focused, and etched images that you hear in many small stand-mounted speakers). Turn the lights down low, pour yourself a glass of Talisker 18yr old single malt, and just relax into your listening chair. There’s no other experience quite like it.
Midrange / Highs
Each Quad speaker has three electrostatic panels – a high-frequency panel flanked by two bass/midrange panels. Many electrostatic designs are renowned for the ability to reproduce the human voice with tonal accuracy. I’ve heard various stats over the years, Martin Logans, Soundlabs, etc, but none I’ve heard capture the human voice in the same way as the 57s. You’ll hear the wonderful tone, timbre, and richness of the human voice like you’ve never heard from a music system before. You’ll hear every inflection, every breath, and you’ll hear the ambient space around the singer come alive with information and become a part of the performance.
Better than voice reproduction is the tonality of strings. You’ll discover for the first time the audible effect of reproducing strings without any coloration. At first, you might be tricked into thinking that there’s something missing. And in a sense, there is. What you’re not hearing is the grungy overlay of a cabinet resonance coupled to a slow-to-respond ‘dynamic’ driver that’s thumping out the music. What you’re not hearing is the shrill woosh of air as it passes through the cupped hands of a horn-shaped driver. What you are hearing, to coin a phrase from the past, is the closest approach to the original sound.
What, No Bass?
That’s right, there isn’t any real low bass extension to be had from the Quad ESL57s, but you already knew that – expect bass output to around 45 Hz, and pretty much nothing by the time you get to 40 Hz. But what you do get is quality bass, natural bass, completely void of any cabinet coloration or boominess.
Those Quad fanatics who need more bottom end will either try to stack Quads, (four speakers, each channel a pair of 57s stacked one on top of the other in a custom frame), or they’ll try to integrate subwoofers into the mix and likely screw things up. I’m not saying you can’t run subs with 57s, just that there’s a way to do it properly, then there’s the way that most people will attempt to do it. Properly integrated, subs won’t get in the way of the Quad magic and you won’t notice that they’re even there. You mustn’t assume that since you were able to integrate a sub with a conventional dynamic speaker you have what it takes to do the same with Quads. Even those of you who’ve had some success with integrating subs with Magnepans, Apogees, or other speakers known to be difficult candidates for sub integration, may need to rethink your strategy. In my experience, the key to using subs with Quad ESL57’s, is to use sealed subs, have a system for measuring the frequency response from your listening position, have some method of equalizing the subs so their output behaves sympathetically with the room, be prepared to position the subs closer to the listening position than the speakers, and accept that the sub output is going to need to be dialed down quite significantly so as not to upset the tonal balance of the 57’s. Also, keep any EQ out of the signal path to the main speakers, and run the 57s full range.
Perhaps I’ll write more on this at a later date, but for now, here’s a list of the equipment I used to get quality low bass with a Quad 57 setup-
- Modified Aerial Acoustics SW12 (pair)
- Crown XLS2502 power amp driving the SW12’s
- HSU VT3 subs for rear corners, pair.
- MiniDSP 2x4HD controlling all 4 subs
- UMIK MIC for room measurement
- REW software
[Of course, there are other approaches available, one option being the use of servo subs, another being the addition of open-baffle bass drivers. In fact, Magnepan makes a bass enhancement module for us with their speakers, the DWM I believe. It would be interesting to experiment with a pair of those alongside the Quads].
Higher SPL Concerns
So low bass is obviously the Quad’s main weakness and also the fact that you can’t play them loud without risk of destroying the panels [and potentially destroying the power amps driving them.] There are modifications that you can have retrofitted to the Quads that essentially provide a current-limiting feature, so you can’t physically over-drive the panels to destruction. My 57s did not have this feature, but even with protective circuitry, you can’t defy the laws of physics and recreate concert levels through the 57.
Back in the day, the ingenious folks at Quad decided to design an amplifier that would act as the perfect companion to the 57s, and by virtue of its low-rated output would not have the capacity to damage the Quads during playback. The amplifier designed specifically for the Quad ESL 57 was the Quad II monoblock. Each channel was capable of a maximum output of only 15 watts, limiting the maximum SPL to around 100db measured at 1 meter from the front of the speaker. Given the increased output produced when operating the speaker as a stereo pair, 100dB might seem quite reasonable. Of course, as you double the distance from the speaker you’re hearing a 6dB drop in sound pressure level, which invites the listener to sit more nearfield to the Quads, as I’d mentioned earlier. So at 6 feet or so from the speaker, you may be able to drive the Quads to around 94dB, enough to enjoy most types of music comfortably. However, if your amps are capable of overdriving the Quads, how is one to know that we’re not going to go over 94dB on loud peaks and transients? And what about the age and condition of our speakers, is it safe to assume that 94dB at 6′ is OK on a relic from the 50’s that’s never had a restoration?
And what about your amps, are they safe for use with the 57, not just from the perspective of the speaker imploding and taking the amp with it, what about the speaker load presented to the amp under normal conditions? The restraining factor on the Quads isn’t watts, it’s actually volts, 33v being the maximum permissible output from an amp before the speaker panels might arc and throw in the towel. As a load, the 57 is hardly benign, it is in fact very reactive with an impedance peak at around 100hz of 40 ohms, a drop down to under 2 ohms in the treble region at 17Khz, and a stated efficiency around 84db/1w/1m.
So you need an amp capable of driving the Quads not just with a 15-watt capacity, but something capable of delivering the goods unrestrained into as low as a 2-ohm load.
No one said Quad ownership was going to be easy.
Living With The Quad ESL 57.
And so we come to the crux of the matter, is it possible to live with Quads and use them as your daily driver? The answer is obviously “it depends”, but from my own perspective, the answer is no.
Firstly, I do like to play loud music loud. Think about that. There’s music that doesn’t need to be played at higher volumes, but some of it does. I call that ‘loud music’. And it isn’t just Rush or Led Zeppelin, think about a good deal of classical music recorded with a wide dynamic range. Set the volume such that you’re comfortable listening to a piano section in your favorite classical piece (the musical term for playing quietly or softly is called piano), then sit and worry like a crazy person that when a forte is encountered, you’ll be scraping pieces of 57 from your wife’s favorite red velvet curtains.
I also think that every track has its own optimal volume setting, where it just sounds right. That’s the main reason I sold the wonderful Emotive Audio Epifania preamp, it didn’t have volume control. So yes, I sit listening to music generally with the remote in one hand and a gentleman’s drink in the other. It’s how I roll. I don’t want the system to be the constraining factor on how loudly or quietly the music should be played. I also don’t want to sit there like a bag of nerves, wondering if the next loud passage that comes along is going to be over the volume threshold for the speakers. And yes, with the Quad ESL 57s, I’ve actually sat there holding my iPhone with an SPL app open.
So for me, the ideal way to own this classic speaker would be to have the luxury of being able to afford and provide space for two separate systems.
Conclusion
It was with a heavy heart that I finally decided to part ways with the classic Quad ESL57.
I placed an ad online and a couple of weeks later a gentleman made the long drive down from the DC area for an audition. He was a nice guy, though clearly not used to being around higher-end audio gear. He didn’t offer up any audiophile ramblings nor did he try to verbalize his thoughts on hearing Quads for the first time. He basically sat there slack-jawed and mesmerized, and would have remained there for as long as I’d allowed him to, of that I’m sure.
CAH 2022
I bought my Quad ESLs more or less by accident. I was getting sick and tired of stereo equipment I quickly got dissatisfied with and was trying to buy better, longer-lasting equipment piece by piece. I went into Smiths Sound, the leading hi fi dealer in Auckland at the time (1976), with a speaker budget of $1,000. When I walked in, du Pre’s very familiar version of Haydn’s C major concerto was coming through a pair of Quads. (These days there is no way I’d listen to music of the classical era on a modern cello.) I later heard a pair of (I think) Monitor Audio speakers meeting my budget but kept going back to the Quads. The price wasn’t as much more than the MAs as I’d expected. They were NZ$1,300. But alas they also meant the obligatory purchase of a new amp set-up. The 33-303 was about $850. When you learn that my income before tax was $120 per week you will realise there was a huge discrepancy between that and the ability to spend this sort of money. It meant going into debt and only two things made that possible: I had a husband and we didn’t have children. We did have a mortgage, but that was interest-only on $7,000 at 7.5%, all we could get at the time.
That, of course, wasn’t the end of the matter. I needed a turntable worthy of my new set-up. The obvious choice was the LP12. It was priced at $850 at the time. But I couldn’t get it for $550, and I could get the Luxman PD131, also priced at $850, for $550 by buying straight from the importer. Along with this I chose the SME Series III tonearm. Price at the time was $330 and I got it for $300. I already owned a Shure V15 Type III so at least that was something I didn’t have to replace. Credit wasn’t available so I had no choice but to use laybuy. Therefore, it was many long months before I could take my turntable home.
The question of bass always rears its ugly head whenever someone mentions the Quad ESLs, yet I was led to believe organists favoured them. It was actually an LP of organ music (from my collection) that one of the two young men who delivered the equipment used to demonstrate them in my home: the infamous toccata and fugue orchestrated by Stowkowsky for the film Fantasia, played by Lionel Jeffries. Some way into the piece I suddenly realised I’d just heard a bass note I didn’t remember hearing before. See also
https://quadrevisie.nl/quadinfo/pdf/a25.pdf
where Geoffrey Horn describes what happened when his son’s friend was having trouble getting sound from the lowest string of his bass electric guitar through his “quite massive” loudspeaker.
As for volume, I have a memory of being advised that for most LPs the 33 pre-amp should be set around 6. I found for CDs that’s more like 4, but for some CDs that’s too much and for others it’s not enough. But for CDs I’ve never had the volume higher than about 4.5. As my living room sizes have been decreasing with every move, I guess that should also be taken into consideration. I haven’t been able to work out what level is suitable for my present very small room (in a retirement village apartment) because my system was robbed of all cables except the speakers’ power cables by a so-called friend who helped with our packing, downsizing, etc. It was part of her revenge because, when she crept into the house to where my husband and I were having a private conversation and asked what we were talking about, I mildly replied, “Oh, it doesn’t concern you, Jan.” While we gaped, she had a hissy fit, crocodile tears and all, before spitefully letting me know she had heard everything anyway, which didn’t surprise me. That was when I realised we never realised she had arrived until we came upon her putting stuff into boxes, and that her eagerness to help people wasn’t kindness but an unhealthy passion for snooping—the now obvious reason why she knew so much about just about everyone.
I feel for you having to dump stuff at the roadside, especially something as special as these speakers. Having to send thousands of dollars worth of furniture and goods to op shops was bad enough for me, though the worst thing was being forced to leave my reasonably big country house (about 2,745 square feet, with 5 acres of land and dairy farms all around). I also feel for you having to finally part with your Quads. I’m hoping to get mine going again. Sheldon Stokes of https://www.quadesl.com has pointed me in the direction of some missing cables and is making others for me. Fingers crossed SHE didn’t do damage to the equipment itself.
I have had nothing done to my Quads. One speaker’s rear light no longer works, and the light on the front of the pre-amp also doesn’t light up, but these are merely cosmetic things so I’ve not bothered about them.
It makes me kind of sad to read you let your ESL 57’s go. Over time perhaps you will reconsider…
My pair dates from the mid ’70’s and is still 100% original, never had anything done to them. Never needed to.
I drive them with a high quality front end: Audio Note DAC 3 sig., a custom-built interstage coupled tube preamp and last-but-not-least a pair of Quad II’s.
I believe the Quad II’s are instrumental in getting the best from the ESL 57. In my experience nothing drives them better. I’ve used the 57’s with numerous tube and solid state amps: pentode and triode push-pull, pp ultra-linear, single-ended. Not even a fully serviced Quad 303 sounds as good as the classic Quad II.
There is a synergy between the ESL 57 and the Quad II that you just can’t get with other combinations, IMHO. It is of course paramount that the II’s are in the best condition possible: a complete overhaul is oftentimes necessary: the original resistors have aged and likely changed value and need to be replaced. Use quality carbon composite types such as Allen Bradley’s and steer clear of metal film resistors as they will change the benign ‘character’ of the amp and spoil the delicate high frequency response of the amp/speaker combo. Metal film types tend to put a nasty glare on cymbals and brass and reed instruments. In case the HT capacitor block needs to be replaced, use high quality electrolitics here. Don’t go overboard on the capacitance value and stay close to the factory spec of 16+16uF.
Coupling caps? Decent quality paper-in-oil types with the same value. Resist the temptation of going for higher values to ‘improve’ the bass response as it will overtax the output transformer and mess up the time-constant in the amp. And don’t be tempted by cheap polyprop types: these flatten out the recording acoustic and change the timbre of acoustic instruments.
The achilles heel of the Quad II is of course the KT66’s cathode resistor as it dissipates slightly more power than its 3 Watt rating is meant to handle. Replacing it with a 10 Watt wirewound type solves that problem. Also, operating the amp with the original tubes gives obvious benefits in sound quality compared to new production equivalents: genuine NOS Osram/GEC KT66 output tubes, Mullard EF86 input/driver tubes and GZ32/34 rectifiers are way superior to anything produced by contemporary companies.
I have set up my ESL 57’s in a fairly small, dedicated listening room, an attic in fact, that has rather good acoustic characteristics and I feed them a diet of everything: from acoustic/electric blues, jazz, pop, rock and folk to classical music. And it all fares sublimely well. In conclusion I must say this: you haven’t really heard what a well-recorded Steinway grand or a Martin acoustic sounds like untill you’ve heard them through a pair of ESL 57’s.
Needless to say they will never leave the house.
Thanks for the great read and info on the Quad II. I suspect I haven’t had my last ownership encounter with the 57. Next time around I’ll be sure to try and track down the amps.
I’ve had my Quad 57s for a good 5 years or more now. It took a few years to find the ideal amp. Love the Quad lls, and the 303 is my “on all the time workhorse”.
But the amplifier that really has me like a child on Christmas morning each time I hear them is the Radford STA25. Just jaw dropping image and holographic detail.
They are not my only speakers, as they don’t provide everything I need (when company is over, only one or two folks manage to sit in listening zone) in terms of volume.
But oh, when alone…. the speakers are gone. Just the music remains. And that, is my ideal speaker!
Thanks for the comment. I agree that these are very special. I keep one eye open on the classifieds hoping a pair might show up locally with overload protection. That was the only real thing that diminished the listening experience, the constant doubt in my mind that perhaps I was over-driving them and risking a catastrophe. I’ll read up on the Radford STA25 that you mentioned. I’ve heard of the amp but I’ve never encountered one in the flesh.
I bought my pair of Quad 57s in about 1986 and use them with my Leak Stereo 20. I had to replace the EHT blocks in the md 1990s but never done anything else with them in 40 years. They must be due for their 60 year service now. I can only say that they are unlike any other speaker I have ever heard.
Mine has been a very long (I just turned 76) journey for a speaker system I could live with. I listen mostly to classical music, opera, acoustic music, folk, acoustic blues, etc. I have some rock and pop music as well, but that isn’t my main interest.
I have owned several horn-loaded speakers from Klipsch and Altec Lansing, panels by Magnepan and Quad, dynamic speakers by many different makers–KEF, PSB, Thiel, B&O, B&W, etc. I tend to like U.K. speakers because they are focused on natural uncolored sound rather than ear-splitting sound pressure levels.
My first Quads were a pair of 63’s which I loved. A pair of ESLs came on the market in a nearby city. I bid about $475. and won the auction. One of them didn’t work, so I sent them both off to Kent at Electrostatic Solutions. There they were fully renovated. I still have the 63s, but I am mostly listening to the ESLs now.
The supposed “no bass” is of no concern to me. I can play Bach and Buxtehude organ music and there is plenty of bass. They will play comfortably at higher volumes than I ever listen to, so that’s not a problem.
What I DO get was mentioned by others. Human voice that is uncannily real-sounding, even opera singers that sound unbearably screechy on other speakers sound fabulous on ESLs. Orchestral strings that sound natural, that, again, don’t screech at high frequencies or volumes. The speakers simply disappear–the sound is just there in the room. No listener fatigue–this is a big issue for me. I can listen to the ESLs for hours and never find myself cringing with screechy sound reproduction.