Walker's "Little Wonder" (Quad ESL 57) - Your Opinions/Experience?

[MattHooper]

Hey folks,

I'm curious about your opinions on Peter Walker's ESLs - from the original ESL 57 to the Quad ESL 63.

Not much needs to be said by way of introduction to those speakers. Quad's Peter Walker was known as a no-nonsense engineer, and the ESL 57 was, as I understand it, the first commercial electrostatic speaker. As we all know it went on to be a classic, still highly lauded in the audiophile world. In fact for many years there was a sort of theme that "every audiophile should own, or at least hear, a pair of Quads at some point."

A fairly classic trajectory for many audiophiles is to have owned Quads, and those that didn't stick with them move on to other speakers, but usually sort of "haunted" by the Quad's clarity/midrange, so the speaker quest takes on a "looking for a speaker that can match the qualities of the Quads...but MORE "(e.g. dynamic speakers moving more air, wider frequency response, etc).

So I'm curious about people's experience or opinions of the Walker's Wonders - the 57 and 63. Any formative experiences? What esteem do you hold them in...or not...these days? Certainly technical discussion of their merits and liabilities are welcome as well.

FWIW: It was hearing Quad ESL 63s at a friend's place that shook my world, the clarity and sense of sound occurring without coming from a box. I ended up buying a pair of 63s, later pairing them with dipole Gradient Subwoofers (made for the 63s), then moved on to dynamic speakers. My friend eventually traded his 63s for 57s, which I found curious - why the backward-in-time step? When I heard the 57s I understood. I too actually preferred the tone of the 57s to my 63s (IIRC the 57s are actually a bit more forward in the upper mids/lower treble).

Nice old article by a writer hearing the Quad ESL 57s for the first time:

Peter Walker's Little Wonder 1956 — Retro Vintage Modern Hi-Fi

I've always been a fan of the Quad ESL speakers but I've never owned a pair. Maybe I'll find a pair local someday. I do have one room left that needs speakers.... Kitchen...

www.itishifi.com

 

[NiagaraPete]

I owned the ELS 63 from 198? to the mid 90's. Loved them, wish I still had them with a couple good subs. I was always bothered by the stands. They sounded better to me without, however the stands did widen the dispersion.

 

[Blumlein 88]

I owned some Maggies briefly. Then stumbled across some Acoustat Two's. So I had experience with and liked panels. Liked the Acoustats much more than the Maggies. Became friends with the fellow who purchased my Maggies. He calls me up one day and said "I've have some new speakers you have to come listen to". He had some Quad ESL63's. I listened to them and told him a few minutes later, "I have to have some of these". So over the next few weeks I found a 2nd hand pair and bought them. Had some with the beautiful Rosewood end caps. I loved them and still wouldn't mind having another pair.

Something that happened a few times with people saying how real they sounded, but this is the best example. A local lady came to my door asking for a donation to a local neighbhorhood park and volunteer fire station being built. With a donation they were doing family portraits. I had some chamber music playing. So I told her to wait I'd go get my checkbook. When I returned she was standing inside between my Quad's. She then looked self conscious and began apologizing for coming in uninvited. "But the music.....it sounded so real.........I wondered how that could be. I'm so sorry." I told her not to worry about it. She went on to tell me her husband had spent a lot of money on a big stereo, but it sounded loud.....loud and bad. Did I mind if he called me so he could find out how to get something like this. He never called. He didn't believe her.

So I had those 10 years. A lightning strike damaged one of them heavily. A fellow had advertised he had one Quad ESL63 and either wanted to sell it or trade a pair of ESL57's for a working 63. He offered an attractive price and I decided to get the 57s just to see what they were about. It was a late production pair in superlative original condition. I was surprised by the amount of bass they had. No real deep bass, but I expected less. They were pretty good to 50 hz. They clearly were a bit rolled in the high treble, but the balance was beautifully done and they sounded great on most any music. They didn't seem to be any less efficient than the 63s. I put together a circuit with led's to warn me if I was getting close to feeding them too much voltage and a another that flashed if I got just below that voltage to make sure they didn't get damaged. They aren't really all that deficient in loudness for any room that isn't huge, but without such a warning system I would have been afraid to play them up to what they really could do. I tried them with a couple tube amps, a good match was a C-J MV50, and I tried them with a Spectral DMA50 which was good on them. Also good with a Brown Electronic Labs 1001 mk. II amp.

Now I don't think they had a better mid-range than the 63's. It might seem so since there was less treble and a little less bass which left the mid-range slightly emphasized. And though emphasized it was a very good mid-range. I thought in fact the 63's could match the mid-range quality and had a more holistic sound. I don't know of anything that sounds like one single driver as much as ESL63's.

I didn't keep the ESL57s very long, never intended to do so. Loaned to a friend for a few months before selling them. He just wanted to experience them. I had intended to get more ESL63's, maybe some USA monitors. Quad was going thru rough times and eventually was purchased by another company during that time. I eventually ended up with some Soundlabs. They are better in quite a few ways, but I'd say not so lovely sounding as Quad ESL-63s.

As for stands, the 57s were on their original little wooden feet. The 63s had the Quad stand with them which I later replaced with some Arcici stands which I thought were better. It held them more rigidly and raised them up a bit. As to subwoofers, I helped other people with them pair them with various subs, and I was never satisfied. I never used them. I've always thought a good idea would be if someone made a large floor to ceiling panel to create a line source using the delayed sections vertically the way 63's used concentric rings with a delay. I think that would give you those holistic qualities and help with beaming and make a bigger panel for a bit more bass and loudness capability.

 

[sq225917]

The trouble with old quads, any older than ten years, is that you can't be sure, without electrical inspection, that they are performing to spec. So with that in mind it's worth discounting some opinions you may find. It's also worth considering the suitable of room placement. Ensure you've addressed those issues and they're capable of amazing sound.

I once heard a set of rebuilt 57 at a diy show in the uk that had me searching for the subwoofer, they were so even and extended it was remarkable. And that's coning from owning 63s and having a friend who has 989 with dual dsp 12" subs.

Get it right and they can be a remarkable looking glass into the recording, as can many other speakers, but I can think of no other 50 year old designs that can do this at even 10x the price with the accuracy of 57s.

 

[MattHooper]

I owned some Maggies briefly. Then stumbled across some Acoustat Two's. So I had experience with and liked panels. Liked the Acoustats much more than the Maggies. Became friends with the fellow who purchased my Maggies. He calls me up one day and said "I've have some new speakers you have to come listen to". He had some Quad ESL63's. I listened to them and told him a few minutes later, "I have to have some of these". So over the next few weeks I found a 2nd hand pair and bought them. Had some with the beautiful Rosewood end caps. I loved them and still wouldn't mind having another pair.

Something that happened a few times with people saying how real they sounded, but this is the best example. A local lady came to my door asking for a donation to a local neighbhorhood park and volunteer fire station being built. With a donation they were doing family portraits. I had some chamber music playing. So I told her to wait I'd go get my checkbook. When I returned she was standing inside between my Quad's. She then looked self conscious and began apologizing for coming in uninvited. "But the music.....it sounded so real.........I wondered how that could be. I'm so sorry." I told her not to worry about it. She went on to tell me her husband had spent a lot of money on a big stereo, but it sounded loud.....loud and bad. Did I mind if he called me so he could find out how to get something like this. He never called. He didn't believe her.

So I had those 10 years. A lightning strike damaged one of them heavily. A fellow had advertised he had one Quad ESL63 and either wanted to sell it or trade a pair of ESL57's for a working 63. He offered an attractive price and I decided to get the 57s just to see what they were about. It was a late production pair in superlative original condition. I was surprised by the amount of bass they had. No real deep bass, but I expected less. They were pretty good to 50 hz. They clearly were a bit rolled in the high treble, but the balance was beautifully done and they sounded great on most any music. They didn't seem to be any less efficient than the 63s. I put together a circuit with led's to warn me if I was getting close to feeding them too much voltage and a another that flashed if I got just below that voltage to make sure they didn't get damaged. They aren't really all that deficient in loudness for any room that isn't huge, but without such a warning system I would have been afraid to play them up to what they really could do. I tried them with a couple tube amps, a good match was a C-J MV50, and I tried them with a Spectral DMA50 which was good on them. Also good with a Brown Electronic Labs 1001 mk. II amp.

Now I don't think they had a better mid-range than the 63's. It might seem so since there was less treble and a little less bass which left the mid-range slightly emphasized. And though emphasized it was a very good mid-range. I thought in fact the 63's could match the mid-range quality and had a more holistic sound. I don't know of anything that sounds like one single driver as much as ESL63's.

I didn't keep the ESL57s very long, never intended to do so. Loaned to a friend for a few months before selling them. He just wanted to experience them. I had intended to get more ESL63's, maybe some USA monitors. Quad was going thru rough times and eventually was purchased by another company during that time. I eventually ended up with some Soundlabs. They are better in quite a few ways, but I'd say not so lovely sounding as Quad ESL-63s.

As for stands, the 57s were on their original little wooden feet. The 63s had the Quad stand with them which I later replaced with some Arcici stands which I thought were better. It held them more rigidly and raised them up a bit. As to subwoofers, I helped other people with them pair them with various subs, and I was never satisfied. I never used them. I've always thought a good idea would be if someone made a large floor to ceiling panel to create a line source using the delayed sections vertically the way 63's used concentric rings with a delay. I think that would give you those holistic qualities and help with beaming and make a bigger panel for a bit more bass and loudness capability.

That was a fun read!

I liked the "local lady" story.

Reminds me of when I played a track of music for an interior designer working for us (at his request). He actually had tears afterward, he found the combination of sound and music so involving. My wife early on was moved to tears hearing Sarah Mclachlan on one of my systems "It's like she's there, singing to me."

I know what you mean in your 63 vs 57 comparison. The 63s do sound very balanced and more coherent overall than any other speaker I remember. I still sort of like the tone of the 57 though. I originally tried pairing my 63s with different subs, including as I remember that little Carver sunfire sub. It always sounded like two different speakers playing, though. The gradient subwoofers were just the ticket. Made specifically for the 63s and dipole to match the radiation pattern. Still the best sub/stat combo I've heard. (Even though they didn't actually go very low).

Friends from work, fellow sound editors, mixers etc, would come over to mine during lunch breaks and listen. They were always blown away. Problem is, especially once the Quads were atop the gradient subs, they were pretty imposing and in our living room took on a 2001 effect, like these photos (not mine):

I'll never forget that "wall of sound" from that set up. Regular sized dynamic speakers tended to sound miniaturized in comparison.Hard sell for the wife though! But it gave me an excuse to to speaker hunting again

 

[Blumlein 88]

The trouble with old quads, any older than ten years, is that you can't be sure, without electrical inspection, that they are performing to spec. So with that in mind it's worth discounting some opinions you may find. It's also worth considering the suitable of room placement. Ensure you've addressed those issues and they're capable of amazing sound.

I once heard a set of rebuilt 57 at a diy show in the uk that had me searching for the subwoofer, they were so even and extended it was remarkable. And that's coning from owning 63s and having a friend who has 989 with dual dsp 12" subs.

Get it right and they can be a remarkable looking glass into the recording, as can many other speakers, but I can think of no other 50 year old designs that can do this at even 10x the price with the accuracy of 57s.

Yes, the age and condition can be important especially with the 57s. The pair I had was from the last couple of years. People forget those were made until 1985. So the pair I had was within a few years of the same age as the 63's I had.

 

[NiagaraPete]

owned some Maggies briefly.

Oh those were horrid. My buddy dad a pair and he loved them. I might have enjoyed them if I could have sat in his chair.

 

[restorer-john]

Sign me up for a pair...

 

[Blumlein 88]

Sign me up for a pair...

Which pair, there is only one pair pictured?

 

[Blumlein 88]

Oh those were horrid. My buddy dad a pair and he loved them. I might have enjoyed them if I could have sat in his chair.

What the Maggies didn't have was a box, which back in those days even most 'good' box speakers exhibited too many boxy effects. Plus even more than current versions the old versions were a nearly perfect 4 ohm resistive impedance which let some less than stellar amps sound perfectly good because the amp was seeing a purely resistive load. Now I do think Maggies reached a turning point of sorts when they started having ribbon tweeters. The 3 series and above are much improved. I still prefer ESLs.

 

[JustJones]

Pair for sale in Germany

 

[anmpr1]

A local lady came to my door ... I had some chamber music playing. She then looked self conscious and began apologizing for coming in uninvited. "But the music.....it sounded so real.........I wondered how that could be. I'm so sorry."

One of my early experiences of drug store high-end audio slumming was at the long lost dealer, The Sound Gallery in Winter Park Florida. Sound Gallery featured the then darlings of audiophilia, the Dahlquist DQ-10, which just happened to have a similar form factor to the Quad. That day a customer had bought the Dahlquist-Marantz wunderkind, leaving behind his former gear, which included Walker's 33 preamp, and 303 amplifier.

Next to a Quintessence (or it might have been an Analog Engineering Associates) preamp, and the monster huge Dunlap-Clarke 'Dreadnought' amp, the little Quad gear looked dinky, and out of place.

I asked for a demo. IMO, the Quad sounded distinctly better. Of course what you didn't get was SPL, and the lows (not that the DQ-10 had much by way of low end, but it had more than the Quad, especially in conjunction with the former's dedicated 'sub'). If I had had the money and space for another system, I'd have bought the used Quad setup, right then and there.

I don't think a Quad system would have made an all-round music system, but it did a lot of things right. Perfect for chamber music. I don't recall much that was 'all size fits all' back then.

The Quad was probably the most legendary of the generally recognized 'high-end' loudspeakers. Not so much in the US, where it always had limited distribution. But even so, it had name recognition. Everyone and his brother used it, in some form or another, even if it was just to compare what they had.

Harvey Rosenberg sold an OTL-1 specifically designed for it. Mark Levinson's HQD was likely the most famous (and expensive) implementation. Polarizing, Aczel thought it sounded great, and used it as a 'template' for his own DIY creation (Koss panels, Janus sub, Sequerra ribbon tweeter). Alternately, Gordon Holt had nothing good to say about it. I wonder whether some of that was due to Mark's 'cost to the end user can't ever be high enough' pricing schedule, which Aczel didn't mind, but no doubt disgusted Gordon, who always possessed a more 'blue collar' value consciousness in his gear recommendations.

 

[dlaloum]

I first encountered Quad in my late teens/early twenties working for a HiFi retailer.... we stocked ESL-63's

I was blown away by the sound - not by its SPL, but pretty much everything else about it.

It was well outside what I could afford at the time...

But looking around at used components (as I did regularly at the time, and still do periodically now) - I came across the ESL57... which was still available new on the catalogue - although nobody seemed to stock it - and most were unaware of it.

I went to check it out, and encountered an Audiophile, short of cash, who had a beautiful TT, set of QuadII valve amps, connected through to a pair of ESL57's.

The sheer beauty of the sound, sweetness, purity, well, here I am 35+ years later, and I still remember how gobsmacked I was.

I still feel that a well set up pair of 57's will better a pair of ESL63's (or the newer Quads) in that absolutely critical midrange.

That means, that for 99.9% of all music, voice, sound, the 57 is one of the best speakers ever made....

And yes, it is SPL constrained, and it's bass is limited (but what there is of it is superb!) and it has constraints at the high end too....

And yet, and yet.... - I have a pair in storage... cannot part with them.

I purchased that pair from the demo mentioned above - I then purchased stands for them, which placed them upright....

Over the years, I have had to replace drivers a couple of times on them, each time, when a guest/visitor "turned them up".... which results in a pretty light show, as the panels arc, and then an expensive visit to the speaker doctor.

They are best operated with an amp which is strictly Voltage output limited - that way the speaker is protected

But perhaps at some point I will seek out the (now very expensive) QuadII amps and pair them up - it is a match made in heaven (or at least in Peter Walkers brain!).

Yes - it is easier to live with the ESL63's or later Quad ESL's - pretty much indestructible, fantastic sound, one of the best - and my long term benchmark.... but the 57's have a touch of Magic that the subsequent speakers lacked.

 

[Blumlein 88]

I first encountered Quad in my late teens/early twenties working for a HiFi retailer.... we stocked ESL-63's

I was blown away by the sound - not by its SPL, but pretty much everything else about it.

It was well outside what I could afford at the time...

But looking around at used components (as I did regularly at the time, and still do periodically now) - I came across the ESL57... which was still available new on the catalogue - although nobody seemed to stock it - and most were unaware of it.

I went to check it out, and encountered an Audiophile, short of cash, who had a beautiful TT, set of QuadII valve amps, connected through to a pair of ESL57's.

The sheer beauty of the sound, sweetness, purity, well, here I am 35+ years later, and I still remember how gobsmacked I was.

I still feel that a well set up pair of 57's will better a pair of ESL63's (or the newer Quads) in that absolutely critical midrange.

That means, that for 99.9% of all music, voice, sound, the 57 is one of the best speakers ever made....

And yes, it is SPL constrained, and it's bass is limited (but what there is of it is superb!) and it has constraints at the high end too....

And yet, and yet.... - I have a pair in storage... cannot part with them.

I purchased that pair from the demo mentioned above - I then purchased stands for them, which placed them upright....

Over the years, I have had to replace drivers a couple of times on them, each time, when a guest/visitor "turned them up".... which results in a pretty light show, as the panels arc, and then an expensive visit to the speaker doctor.

They are best operated with an amp which is strictly Voltage output limited - that way the speaker is protected

But perhaps at some point I will seek out the (now very expensive) QuadII amps and pair them up - it is a match made in heaven (or at least in Peter Walkers brain!).

Yes - it is easier to live with the ESL63's or later Quad ESL's - pretty much indestructible, fantastic sound, one of the best - and my long term benchmark.... but the 57's have a touch of Magic that the subsequent speakers lacked.

Quad designed a protection circuit for the 57s. I also think some restorers will add one. As I recall it only protects the bass panel, which perhaps is because most power in music is in the lower frequencies.

It also is not much of a problem to add a pair of resistors to attenuate the input of an amp so that you can insure it never puts out dangerous voltage for the speakers. They were supposed to never see more than 33 volts peak which in RMS works out to 68 watts into 8 ohms. So with 50 watt amps you might be fine or might need to attenuate the input only slightly to protect the speakers from arcing over.

 

[dlaloum]

Quad designed a protection circuit for the 57s. I also think some restorers will add one. As I recall it only protects the bass panel, which perhaps is because most power in music is in the lower frequencies.

It also is not much of a problem to add a pair of resistors to attenuate the input of an amp so that you can insure it never puts out dangerous voltage for the speakers. They were supposed to never see more than 33 volts peak which in RMS works out to 68 watts into 8 ohms. So with 50 watt amps you might be fine or might need to attenuate the input only slightly to protect the speakers from arcing over.

QED used to make a speaker protector, an outboard device, which I used on the ESL57's for some years.

Not sure how well/whether they protected them.... in the early days I was in a shared student household.... most listeners were astounded by the ESL's - but there was always the one or two that would head straight for the volume knob.

Chances are the QED protector saved me a number of times... still have them...:

 

[anmpr1]

Quad designed a protection circuit for the 57s. ... As I recall it only protects the bass panel, which perhaps is because most power in music is in the lower frequencies. It also is not much of a problem to add a pair of resistors to attenuate the input of an amp so that you can insure it never puts out dangerous voltage for the speakers. They were supposed to never see more than 33 volts peak which in RMS works out to 68 watts into 8 ohms. So with 50 watt amps you might be fine or might need to attenuate the input only slightly to protect the speakers from arcing over.

One of the weird things about the 'high end' back then was the idea you'd frequently come across in the mags, stating how protection circuitry had a negative effect on the reproduced sound. Then, you had amplifiers that supposedly 'sounded' good, but were designed and sold with substandard protection. The infamous Quatre Gain Cell amp comes to mind.

Quad 405 shipped with plug-in current limiters (1.8 K Ohm resistors) that reduced output voltage. Again, the tweako press told readers 1) the amp didn't 'sound' the best, and 2) the resistor made matters worse.

FWIW, to my mind the 405/33/ESL made a wonderful package. For certain recordings. You needed a set for the Amadeus Quartet. Alternately, L100s and a monster amp worked better for the Allman's Whipping Post, recorded at their Fillmore East gig.

 

[DSJR]

We sold the 57's new and they really were an odd-ball even in the mid 70's. with a superficially 'nasal plastic diaphragm' kind of tone compared to the Bextrene-cone boxes we sold normally (Spendor, KEF, IMF amongst the better ones). One of our part timers had a set at home and a friend who was interested to buy some and I went to hear them in around 1978. We both fell in love with them and said friend bought a pair and used them until she passed away in 2014 or so. First amp was a 44/405 (the amp limiters tended to appear to sap dynamics and she didn't play loud, so we took them out) and then after the limiters were fitted to the speakers, the 44/FM4/405 became a 66/FM66/606 and the added gentle clarity the 66 gave was very much loved by myself.

At their best, it takes half a minute to settle into the listening position to best use the beaming highs and then to get used to the 'tone' of the speakers. After that, they disappeared from the 'sound' and the music fully took over

Thing is NOW, the panels will be getting tired (one of said friend's pair could 'vibrate' on bass but that could have been a fixing internally rather than a worn panel), I'm not sure if the same diaphragm film is used these days (UK restorer One Thing Audio were happy their tweeter panel replacement increased hf output by 5dB as the audiophiles liked it, giving a pronounced saddle-back response according to HiFi World who measured them). They don't do bass below 80Hz and don't go loud either (about the same as the infamous LS3/5A really). So, be warned if you're tempted for a once reference retro speaker so far ahead of the 60's game it's untrue...

The 63's were a bit different and my first hearing of them on the Quad stand at a HiFi show (Heathrow?), plonked on the floor and hf cut well in use was incredibly disappointing. I gather they came out before their proper time to help Quad out financially. Hearing them in our large dem room on Quadropod stands helped so much it wasn't true. The Arcici stands held them at the sides and this helped stiffen the frames a little (nobody at Quad knew much about that 'pop music stuff' I think ). At their best, the 63's easily took over from the 57's (Naim amps still didn't like them much) but they don't seem to stand the test of time as well as their predecessor, with panels coming apart due to adhesive failure, although they can more easily be serviced I gather.

The desktop Quad book is fascinating in its revelations about these speakers. The 57's were labour intensive (PW didn't want to revisit the design once signed off) and the 63's apparently needed every sample to be extensively 'Quality Controlled' before being fit for sale. Neither were profitable I read but those who knew these speakers usually fell in love with them.

One little anecdote from before the time of the 63's. One Heathrow? audio show Quad room had 57's sat on trestle tables and rows of seats where visitors could sit and relax (and maybe guzzle a sandwich or a drink). The 'sound' in that room was absolutely wonderful, an audio-oasis and so much better than the booming drones at high volume everywhere else....

 

[anmpr1]

We sold the 57's new and they really were an odd-ball even in the mid 70's. with a superficially 'nasal plastic diaphragm' kind of tone compared to the Bextrene-cone boxes we sold normally (Spendor, KEF, IMF amongst the better ones).

I've encountered that description for other electrostatics. In fact, I owned a set of Acoustats (actually, three sets crossed my path). The best of the bunch was, IMO, the 2+2s, which were tall and narrow. So you didn't get the vertical 'beam' (although the horizontal remained a problem). One day an acquaintance with a good ear came to listen. He casually mentioned that the Acoustat's imparted a 'plastic' credit-cardish kind of sound to the music.

Well, that did it for me. I never noticed it before, but from then on all I could hear was his plastic credit card analogy. You know, the sound you get when you pick or ping the card. Shortly thereafter I sold them. Shortly thereafter I sort of missed them. Nothing is ever one size fits all, it seems.

As an aside, in the US, original Quad distribution was (as far as I know) via Bud Fried, a hi-fi salon owner in Philly. He imported them, sold them through his store front, and probably mail order-- I don't know about that. This was in the mid '60s, I believe. The few who owned them might use Paoli modified Dynaco amplifiers. McIntosh or Marantz tubes, and so forth.

When four channel Japanese systems were becoming (not so) popular, Quad ran small ads in Audio magazine warning people that the word 'quad' was trademarked, and had nothing to do with four channel sound hardware. The company argued how in the vernacular, the press should stop using the word 'quad' to mean four channel audio. But by then it was too late, and no one cared. No one cared for four channel, and few had ever heard Quad ESLs. Besides, Quality Unit Amplifier Domestic sounded too much like what you'd find in a sealed can, in a K-Ration.

 

[DSJR]

The thing for me was how quickly one got used to the tone, which simply disappeared after a minute or so. the 57's especially 'did' massed string tone if anything too well, that 'rosiny' kind of nasal 'eeehhh' sound just as heard live - very few boxes did that, adding the 'box' to the tone (I'm thinking of my comments the other day with @Purité Audio about the Kii Three being a bit 'lean' and definitely not having the boxy warmth I may have got too used to. Got to try to hear some of the newer state of the art actives now. In the meantime, if any of you lot have 57's, take great care of them and enjoy a speaker that really WAS way ahead of it's late 50's time in so many ways

 

[MattHooper]

Quad designed a protection circuit for the 57s. I also think some restorers will add one. As I recall it only protects the bass panel, which perhaps is because most power in music is in the lower frequencies.

It also is not much of a problem to add a pair of resistors to attenuate the input of an amp so that you can insure it never puts out dangerous voltage for the speakers. They were supposed to never see more than 33 volts peak which in RMS works out to 68 watts into 8 ohms. So with 50 watt amps you might be fine or might need to attenuate the input only slightly to protect the speakers from arcing over.

Never having owned the 57s I've never put any thought in to the ESL 57 arcing issue.

But I do have some access to borrowing the 57s if I want. Would my CJ tube amps at 140W/side pose any particular danger in running the 57s?