Looking for vintage Quad ESL's - or my wife thinks a "shrink" becase she says I'm crazy!


Been out of the hi-fi ’scene’ since the early 80’s. My last system was a pair of Quad ESL-57’s with a Quad 303 amp, Hafler DH101 pre-amp (kit I built) and a Linn LP-12 and Grace tonearm (can’t remember what cartridge I had). I bought all of it for a song back then. The speakers were $300 (nobody knew what they were or what they were worth), I got the LP12 for $500 (salesman accommodation). The power amp and pre-amp were $200 combined. Oh yeah, I worked at a hi-fi store in Chapel Hill NC which explains some of the deals I got. Sold *everything* to pay for a down payment on a trailer as I had just gotten married. Skip 35 years, raised three kids, put them all through college, worked as a software engineer until retiring. Now I want to get back into my original passion. I can’t afford to buy new stuff, the price has gone ballistic. So, I’m beginning again to put together a system to listen to my music on. I still have my Hafler pre-amp which I will use if it still works until I can get something better. I just bought two 125 watt monoblock tube amplifier kits from Bob Latino (www.tubes4hifi.com). I love building things and am very handy with a soldering iron! Also, I always loved the sound of tubes.

Speakers...That’s where I need help. I *really* loved the way my old Quad ESL-57’s sounded. When I was 15 (I’m now 66) my friends dad had stacked Quad ESL-57’s and I swear I’ve NEVER heard anything as good since then! That’s why I’m really wanting to go back to electrostatic speakers. I’ve auditioned some of the Martin Logan stuff at Best Buy. I’m astounded that they are distributed in that chain..I also was flabbergasted that McIntosh was sold there too. Regardless, the salespeople don’t know what to demonstrate let alone setup up quality hifi equipment. They sounded terrible. Even after listening to the ML speakers on several different occasions I concluded I don’t like the way they sound. I still think a proper pair of Quad’s is the way to go. The problem is finding a pair! I’ve discovered Electrostatic Solutions LTD and if I get a decent looking pair intend to have them rebuilt there. I’m guessing after I find a pair and get them refurbished I’ll be spending between $4K and $5K. Unless I find a great deal on a pair that is already up to snuff.

DAC - I never knew what a DAC was until recently but conclude that I need one since I will be listening to music streaming from my iPhone, my Mac Mini etc. I feel really ignorant on what kind of DAC I need. I’ve noticed that some of them can double as a pre-amp too and hook directly up my power amps. That might be good for a temporary solution until I can get a proper preamp. Still, DAC’s can range from $500 - $15K. I have no idea what features I need or whether the low end DAC’s are even worth it.

I really need some suggestions. If I had the money I’d go to an audiophile salon and buy my equipment proper. But I don’t so I have to get the best equipment I can with my limited resources. I’m not exactly poor, but I could never justify to my wife spending $20K on audio equipment. Dang, I looked into getting another Linn Sondek LP12. The price is sky high compared to my ’82 version although there are differences between the basic model I had in 1982 and what they’re producing now. Still...I may need to wait on a turntable until I get speakers and a DAC.

I feel overcome with choices! New gear, used gear, electrostatic speakers, conventional speakers... Maybe my wife is right. I need some Valium and a good shrink!!

Mark in Big Stone Gap VA

markcooperstein
In my collection I have: Quad 57's (two pairs), Quad 303 (upgraded), Hafler 101, Linn Sondek/Grace 707. These components (old as they may be!) put together make a great-sounding system!   So I recommend buying a pair of Quad's in good condition (may not need any repair) and a 303 (ditto) as a start.              Next add a signal source (analog or digital) and a preamp (the Hafler 101 is fine and easily modded). For LP's I recommend a Pioneer PLX1000 and a Denon 103R mc cartridge (I have and use this combination). Digital source can be an Oppo 105 (no need for an expensive DAC!). All of the above equipment can be bought at a quite reasonable price (no need to spend many kilobucks!). Regarding interconnects and speaker wire: from my long experience (40+ years) the cheap stuff sounds no different than the expensive stuff (contrary to untutored belief!). So beware of people touting the benefits of fancy and expensive wire, particularly power cords!
I live in an apartment so my Quad 57's remain in storage until I can free up some more space! I bought my first pair in 1982 and kept them in use for 19 years (until I stupidly sold them!). The amplifier I used for all that time was the Bedini 25/25 (still have it!).
Your Bob Latino tube amps would be a mite too powerful for the 57's - unless some protection circuitry was added. No more than 20 volts peak was the factory recommendation! A Dynaco ST70 would be ideal - pp EL34's with 35 watts output. I have two (both modded). 
If you are intent on using the Latino amps then the later Quad 988 or 989's would be a better choice, as they already have protection circuitry!
Among many the 57 is still considered the best speaker ever produced !http://www.theabsolutesound.com/articles/the-12-most-significant-loudspeakers-of-all-time/
Give this place a call. They have a great reputation!
http://www.quadsunlimited.us/
Robert, thank you so for your valuable information! I took your advice about the Bob Latino amps. I will use them ultimately when I can make sure I have taken the appropriate measures to protect my future Quads from damage. I'll have to email Bob Latino about the proper way to add protection circuitry. In the meantime.. I went out and bought a Quad 303, 33 and FM3 tuner on eBay. I got all three items including the wood cabinet that holds the 33 and tuner for $795. Here's s link to see what I got: https://www.ebay.com/itm/182974685598

Next will be the speakers. Thank you Yogiboy for your suggestion for Quads Unlimited as a resource to get advice, parts, total refurbishment if necessary. Thank you!

Mark
Post removed 
I heard a pair of reburbished Quad 57s at Capitol Audiofest. They sounded great.
A really good buy on that Quad gear, Mark!
You've already discovered Kent McCollum at Electrostatic Solutions- can he help source a pair for rebuild?
I bought mine in 1973 and used them until 1990 when I changed to the Crosby modded Quad 63. The original pair was put in crates that were left untouched 2017 when i sent them to Kent for a long overdue restoration. They are now better sounding than new. I love them- they are, to me, the reference for midrange, and despite their limitations, I could live with them as my main system. (I have a bigger more elaborate horn based system, but the Quad, particularly the original, makes you question how much we have really advanced in terms of sheer musical satisfaction).  
Going to a hi-fi salon to buy new equipment isn't necessarily the right answer even if you had mad stacks of cash. Not dissing dealers, but used and vintage equipment, properly brought to spec, can yield huge musical satisfaction at a fraction of the cost. There is a large community of old Quad users whose knowledge you can tap into about systems, associated gear and the like. Welcome back to the fold!
My first system in the 1970's and used until quite recently was an LP12/SME/V15iii, Quad 33/303/fm3 (twice refurbished), Quad ELS57. It sounded great. A few years ago I replaced the ELS57s with the Quad 2805s, and these really are better, even the difference is not night and day. The 2805s are less sensitive and combined with a larger listening room, I now also needed more power, so a refurbished second hand Quad 606-2 replaced the Quad 303. The result was a cleaner sound on louder more dynamic passages. But as long as the room is not too large and the speakers not as insensitive as the 2805s, the Quad 303 should be fine (and if you insist on the ELS57, anything more powerful may destroy them - the 303 is the perfect match for the ELS57). In recent years I have of course added a CD and later Bluray player (make sure the input sensititivity of the Quad 33 is reduced to cope with these modern sources, or use an attenuating cable). These days I hardly listen to the LP12 anymore since I find digital sonically far superior. And most recently I have entered the world of streaming from services like Spotify/Qobuz/Tidal. The streamer is a Chromecast Audio. I use its analogue output into the tape input of the Quad 33 and it sounds great if you make sure levels are properly matched (the Quad 33 is perfect for that). You do not need an expensive streamer - the $35 Chromecast is fine. I also use it for internet radio. In fact, the FM tuner is not really used anymore, because internet radio, though not perfect, is at least as good as FM (though with different deficiencies). And you can bring the world into your living room.
I wish I had more room. Quads and Maggie's were always on my list.
B
You can confirm your wife's diagnosis by going with the stacked Quads.  ;~)
Good ears you have.

I have owned three types of Magnepans and three types of ESL's. I say Quads, hands down.

ESL 57's are wonderfully musical speakers. 2805's add an octave high and low but sound a tad bright to me, while 2905's add those octaves and restore that Quad magic. Some gently used 2905's might be more reliable than 57's, and not much more money.

Another thing is that 2905's beg to be tweaked. Since you are handy with a soldering iron, you might consider hinting to your wife about some aftermarket Plitron transformers for Christmas this year, some better caps next year, etc. Choose the mod-upgrade path to that superb system.
I have a pair of stacked quad 57s since 1996 and i love it for playing string music and female voice.the problem with quad is that it is not reliable, especially can not play too loud so that they start arcing.
I built a infinite middle range ribbon and old paper cone full range woofer based bi-polo speaker system and really like it, it is as fast as quad w/ better high frequency response and play much louder than quads.

Driving quad 57 is challenging for solid state amps, better use push pull transformer coupled tube amps. Stay away from using "otl" tube amplifiers to drive quads.

Byang, must disagree.

I have found Quads to be perfectly reliable - but then, I have never pushed them hard.

As for OTL's, as I understand, it is true that a good protection circuit is necessary, because if something goes badly wrong, it can send a pulse through the speakers. 2805's and 2905's both have adequate protection, 57's do not.

I ran Atma-Sphere M60 OTL amps for biamping ML ESL's, as well as 2805's and 2905's. One of my friends has stacked 57's, and the M60's worked fine with one pair of those. The issue is something going badly wrong, as discussed.

True, Quads won't play as loud as some would like, but they're plenty loud for me.

Not crazy at all.

I've been through a ton of high end speaker systems since the mid 90's and I still lust after a pair of ESL 57s.  I'd have some now if I had the space.  (But they won't work in the setup area I have to work with).

Ok, what does OTL mean? "On the Lamb, Oh.. Too Loud!" I give up!!

So, if I get a pair of ESL 57's and if I wanted to use my brand new M125 tube amps how could I add 'protection' to the Quads so I don't destroy them? BTW, I don't particularly like loud music anyway, one of the reasons I always loved my old pair of 57's. Playing them at normal listening levels was quite satisfying. I think I got "loud music" out of my system from the 70's when I went to too many Grateful Dead concerts and sat right next to the speaker arrays! That, coupled with spending years in loud computer rooms (Thank you VAX 11/780 for my hearing loss!).

Now I'm also going to consider 2805 or 2905's. "She who MUST be obeyed" insists that I pay off some of my investments first before delving into speakers (I just dropped $795 for a Quad 303/33/FM-3 from eBay). I still am leaning towards the 57's, mostly for sentimental reasons. The best system I've heard sentimentally, was when I was a teenager in the 60's and my friends father had stacked Quad 57's. The subwoofers were built into the back wall. I remember he had a ton of sand poured into the wall to help the bass acoustically. His "she who must be obeyed" had a fit! He also had tweeters on the top of the Quad's. I want to say they were Ionovac?? They 'glowed' purple when they were on. Anyway, this system rocked! I remember he originally had the Quad's powered by Quad amps, then went to Mac 2105's. Arty (my friends dad) used to take his Crown CX822 to record the West Point military band in West Point NY. I also remembered him blowing out the Quad's one day listening to his tapes too loud using the Mac amp!!

Last question..Someone above recommended an Oppo 105. What is that? I found an Oppo BDP105 Blu Ray player. Is that they were suggesting for an DAC? Oppo also makes a reasonably priced DAC called "Sonica".

Sorry for the verbosity. I get carried away when I'm excited! My Quad Amps should get here in a week. I can drool over them while I'm waiting to get my speakers! I suppose I could hook them up to an old pair of RTR floor standing speakers given to me by my sister.

OTL means "output transformer less"  - NO output transformer for the tubes! These are the rarest and most problematic of tube amps! Atmasphere (Ralph Karsten) makes some excellent ones! They can drive Quads quite well!      I myself still own a pair of Julius Futterman H3AA's and a Harvard Music H3. They also can drive Quads and KLH Nines very well!
I recommend the Oppo 105 as a digital player for all formats (that sounds excellent).
An amp greater than 30 watts can be used with the 57's as long as you are careful with the volume control and loudness level! Otherwise stick to a 303 or a Bedini 25/25 (both of which I own).    For tubes a Dynaco ST70 (easily nodded!) is a great match (got two!).         And among new SS amps the First Watt F5 and clones (got one!) will do well!
I’ve said it before and I’ll say it again, the heavy metal grills on the Quads are bad news. They rattle, they hum, they block the sound on both sides. Hel-loo! The Quads need to breathe. Remove the grills and enter Audio Bliss. Remove the plastic dust protectors and enter Audio Nirvana. 
Marc, it's a great thing to be excited about great prospects, is it not?

I agree with Roberjerman about Quads and amps, but have no opinion of Oppo, except that my dealer recommends them.

I recommend against adding subwoofers or tweeters to Quads, until you have stabilized your system. These can be highly problematic and very difficult to get right. Get the basic system right first.

Compare the 2905's, which will do most of it very well, and provide a coherent sound. By 'coherent', I mean that all frequencies are produced by the same technology, and so bass doesn't sound like a cone source and treble like an ESL; the 'cello sounds 'coherent' with the violin.

I also suggest you stay away from expensive cabling. In my experience, it's the least bang for the buck. I have a six figure ESL / vinyl system and use good microphone cables, $1 / foot. Just make sure that the RCA connectors are non-magnetic. ETI makes good ones. DIY for ever!
You can buy all the parts necessary for your Quad 57s on eBay or directly from Kent at ESL. You would need the protection circuit board and while you are in there might as well install an upgraded power supply board. The parts are reasonably priced, so your challenge is you install them well or pay well to have them installed. After that enjoy your speakers with the amp of your choice.

About the only negative in the 57s is the 90 Hz resonance. You can sometimes hear this when the speaker slaps/vibrates on loud passages. You can avoid this by biamping with an active crossover cut at 100 Hz. I use 4 passive bass speakers placed asymmetrically around the room, Atmasphere or Music Reference OTL on the 57s, Luxmam M-02 for the bass speakers. It's stacked quads without the stack.
@markcooperstein, "When I was 15 (I’m now 66) my friends dad had stacked Quad ESL-57’s and I swear I’ve NEVER heard anything as good since then!"

I very much agree with you.  I doubt you will hear anything as good going forward, either, including the subsequent Quad electrostatic offerings.  Those that followed certainly sound different, and may have addressed some of the issues that folks had with the original.  But they also took some things away.  For many, including myself, a magic and rightness exists in the ESL57 that doesn't elsewhere.

@markcooperstein, "I still think a proper pair of Quad’s is the way to go. The problem is finding a pair! I’ve discovered Electrostatic Solutions LTD and if I get a decent looking pair intend to have them rebuilt there. I’m guessing after I find a pair and get them refurbished I’ll be spending between $4K and $5K. Unless I find a great deal on a pair that is already up to snuff."

You're right in terms of pricing for a rebuilt pair.  Considering so many loudspeakers today carry the price tag of a good new car, yet don't bring near as much happiness, you've found something offering great value.  Actually, they are pretty easy to obtain here, ebay, or the other sites that specialize in high-end audio gear.  Best to stay patient, and give yourself at least a few months to land the right pair, though if they appear, don't dither.  You don't necessarily need a pair that's already rebuilt.  So many of those offered on the used market still work fine.  If you come into some with no issues, use them and enjoy them.  If / when the time comes for a rebuild, then you can cross that bridge at the point.

Finally, your Bob Latino amplifiers should mate with the Quads fine.  A rebuilt pair normally include the protection circuitry.  If you move on an original pair, remember so many drove theirs for very long periods of time without issue using Dynaco amplifiers back then, including the MKIII monos these are based on.  Presuming you don't go nuts, the speakers should not have any problems
Well, I have both the ELS 57 and the 2805. As I said before, they are of the same family, but honestly, I can compare them directly next to each other. The ELS 57 was a brilliant speaker for its time, but the 2805 is really better. It has a more extended bass response, a wider less directional pattern, and most of all a far more natural spatial representation and a cleaner sound.
Terry9,
I do not think you really is a audiophiler  since you can not tell the difference between quad 57s being driven by transformer coupled tube and otl amps. 
I have owned 4 diff otl type amps to drive both sound lab and quad electrostatic speakers.
The only one has enough juice is 3c33c based monster mono  block otl amps.
Others cant deal with sound labs at all and have high distortion such that the best quad 57s decayed sweet
miiddle range got lost.
The problem with otl amps is they have very low damping factor and have heavily applying negative feedback to stablelize the amp, which is against the audiophilers‘  principle
 of no negative  feedback in power amp.
Actually if you have a ee  degree, you should know all otl amp is cathode output amps, which have embedded negative feedback,degrees sound. 

please byang12, NO bad juju in my thread! Everybody is welcome to their opinion, even you, a 'true audiophile!'


Mark

Good for you Mark, put your heart first! Love is a beautiful thing, right up there with passion. It's why we're here. Shrinks need the straight jackets they created, meanwhile we'll keep that secret smile on our faces!

;-)
Mark,
God loves "juju", and we will pray for your happiness. One nation under god, no thread is beyond this sea of loving. No 
Kneeling  down and no smile, just pretend.
I run my rebuilt by Wayne Piquet Quad ESL57’s with a Jeff Rowland Concentra 2 integrated amp.  It always sounds wonderful and never have had any issues.  Volume is just fine for me and the midrange is beyond description, as well as the most amazing soundstage.  

They truly disappear.
Mark,  I bought my pair of 1960 era quads in Piney Flats, TN, which is not too far from you.  I drive them with either a Mac MC240 or a pair of Klimo Kent amps.  When I bought the speakers they were arcing during the audition. Using numerous online postings as my guide, I replaced the arced treble panel with one I bought at auction and had shipped from England for about $80, upgraded the power supplies with new parts, added clamp boards (also purchased from England) for protection and replaced the dust shields.  The process of fixing them was not hard and did not cost much money and since you have the skills to build an amp and a preamp, I doubt you will have any problems with repairing a pair.  From what I have read, the treble panels are usually the panels that arc so I would guess that most used pairs would have good base panels.  If I was hunting for another pair, I would find a pair of original, unmolested, speakers and fix them.  There is a very large price gap for a pair that have been refurbished and a pair that someone found at an estate sale.

The outfit that I bought the new parts from also sold new or rebuilt panels (I don't remember which) and he suggested that the his panels would not sound as good (or maybe it was the "same") as a good working original panel.  I am not sure about that as those who have had their Quads rebuilt report that they are often significantly better than original.  However, I do love the way mine sound and would not trade them for anything else I have heard.

Good luck.




If you want an alternative to the Quads, don't look to modern Martin Logans, look to vintage speakers.

I run original CLS all electrostat speakers in one of my systems and there is something about them - the same way there was something about the 57s.
cool story and prediciment
take the meds slowly and without a drink
tell wife you ARE seeing a shrink......goes by name of Agon....must be Greek....

our path somewhat similar I also made my way thru University selling very high end gear, then got away from it....no matter...

congrats on your retirement !

keep the Hafler 101 for now but upgrade it with mods and better parts. Ditto with the amp kits you have already purchased
- dont go backwards just to get ESL 57 ( yes I have owned them including stacked pair, etc... )
you can and should look at the later Quad models with real bass ( well small room English electrostatic bass anyway ) that also have the delay lines, those present a much more accurate waveform, a normal panel stores energy like crazy..but that is just math and physics..
they as others have pointed out also MUCH more compatible and safe with your amp choices

table...why not find a used LP12

but a SOTA saphire will sound better IMO
get the Grace arm again
get a nice Ortofon ( black) that will sing in the midrange....
get a Lampizator Atlantic tube dac....off to the races...
I've been a Quad 57 owner for years and have finally replaced them with Harbeth 40.1's. You have to have a large sized room for these but when you sit at the apex of a equilatrral triangle with them, they are every bit as transparent as the Quads and are not limited in their dynamic range. There are several used pairs out there for sale but the new 40.2"s will cost about $16-18K. A used pair of 40.1's should cost about half that much. Your amps should be a good much as they perform better with higher powered amps
I possesed Quad esl 63, quad 909 amplifier, quad 34 and quad 303/33. I was a big quad fen. Today, we are in 21st Century, and there are a lot of other stuff much better then quad. 
I would sugest to forget about quad and buy Maggies 1.7i or 1.7, two Schiit Vidar amplifiers running in mono using balanced interconnects. If you want to save money on pre buy used PS audio Perfect Wave Dac Mkll with network bridge. Connect PWD with Vidars using balanced. Buy Roon and install it on your Mac Mini and then stream your music and/or Tidal hifi using your network bridge. Maggies are so much better then quad ‘57!  I currently have the above setup and this is my honest sugestion.
@willemj "The ELS 57 was a brilliant speaker for its time, but the 2805 is really better. It has a more extended bass response, a wider less directional pattern, and most of all a far more natural spatial representation and a cleaner sound."

You're right about the 2805 (and other Quad electrostatic loudspeakers that succeeded the ESL57) in terms of more extended bass response and a wider less directional pattern.  However, your statements about far more natural presentation and a cleaner sound, and the overall summary of the 2805 being really better are purely subjective, and I happen to believe the opposite.  I understand the arguments for the later loudspeakers addressing the wrongs of the original.  But the company created other issues, as well.  Many people do feel the ESL63 and later offerings bested the ESL57. And likewise, a large, dedicated cadre believe the ESL57 continues to represent Quad's finest offering.

For me, the originals and solely the originals have that true to life timbre / tonality, clarity, speed, lively and engaging demeanor / sparkle, and uncanny sense of imaging within that admittedly narrow sweet spot.  More than any other loudspeaker, the ESL57 sound like real life to me.  You could say that's the magic in them
A modest and cost-effective proposal:  Magnepan .7's.

Reliability issues? Zero. Made in America?  Yes. Great and easily accessible customer service?  Yes.

I power mine with excellent mono tube amps.  Perfect? Of course not. ROI? Considerable.  A cure for audio nervosa? Definitely a contender.

YMMV
Mark: Stick to your guns regarding the 57s.  Several posters have correctly defined the truth and magic possessed by these speakers, and your recollection is also spot on.  They are wonderful stock but in many ways enhanced by the updaters, particularly Quads Unlimited.  I bought my pair through QS&D in Virginia many years ago, who were some of the earliest to mod these speakers.  They are fed through 1 M Highwire cables by LA Audio SETs with two 300Bs per side making about 15 delicious watts.  I later added a single REL Stadium Woofer which can be precisely dialed in as to crossover and levels to provide a subtle bass foundation that takes nothing away from the midrange and treble excellence of the Quads.  The only electrostat that I have found even close to the 57s was the original Acoustat Monitor 4 that possessed truly great electrostatic bass (particularly after the amps were updated by Joe Curcio) but was slightly less transparent in the midrange.  BTW those amps were tube OTLs used only for the 3 and 4 panel Acoustats, and I do not recall employed much if any negative feedback.  ML's best speaker, the CLS in various forms is very expensive and could not best the 57s in my estimation.  Long live vintage audio!
The quad speakers are almost unpossible to mach with any sub. Yes I agree with others ‘57 is best sounding quad speakers especially runing with 405 not 303. 405s current dumping is exceptional! Thats why I recommend Maggies. .7 if you dont have space or 1.7. Or 3.7 if you can... .

One of the most impressive speaker sets ups I’ve owned were the Quad ESL63s with Gradient subwoofers, which were dipole pattern subs made by Gradient specifically for the 63s. Visually, the mated seamlessly. Sonically, they were the only mating of a subwoofer/electrostatic speaker I’ve ever heard that was virtually seamless.

That was essentially the benchmark of boxless transparency, realism and quality of midrange information, I’ve been trying to keep up to ever since, but in dynamic speakers (because I like the extra body of dynamic speakers).  They created a huge wall of transparent sound - very full in the midrange. 

Though my pal, who I bought the 63s from, went for 57s after that and it was sitting down in front of the 57s that made me understand their appeal. Trelja put it well:

"For me, the originals and solely the originals have that true to life timbre / tonality, clarity, speed, lively and engaging demeanor / sparkle,"


That’s what I hear with the 57s, a more golden, beautiful tone that is just to die for. I’d find myself envying my friend’s 57s on that count.

I actually prefer the tone/timbral nature of the 57s and a number of dynamic speakers to the 63s, which is one reason I moved on from them. But boy were they a nice place to visit, and spoiled me for a long time!  (My next speakers were Von Schweikert VR4 Gen2 speakers which were at the time about the only (remotely affordable) dynamic speakers that actually presented a sound like I heard with my Quad set up - giant, boxless, but absolutely full and rich in the midrange, but went deeper in the bass.  Loved them, but moved on to other speakers whose tone called to me...)
Quad owners (actually, owners of ANY planar speaker) who want to add subs that blend invisibly are missing the boat if they ignore the GR Research/Rythmik OB/Dipole Sub. The design is very similar in concept to the Gradient prof mentions directly above, but much better executed, with superior woofers, H-frame enclosures, and power amplifiers that incorporate the Rythmik Servo-Feedback system. The amp also includes a shelving circuit to offset the front-to-back cancellation inherent in all ob/dipole speakers. To see what the sub looks like, check out Audiogon member kennythekey’s virtual system.
I agree that dipole subs are indeed a very good idea for Quads because they excite fewer room modes. However, in my experience even ordinary subs can be integrated very well if you use room equalization like the Antimode 8033.
And the price including ‘57s and sub and risk of successful implementation equals more then it worts the effort.
The difference between quad speakers and Maneplanar 1.7 and above is that human voice or the instruments sounding in their real size, and this is the only one exemple. Some may argue about their lack of dynamics, but compering to ‘57 its a huge improvement. I tried many speakers, quad amplifiers and preamplifiers, tube amplifiers, dac’s etc. In my humble experience over 45 years, my suggestion stays, dont bother with 20 Century stuff. 
+ps
My first love for speakers was a pair of Quad ESL 63s. Nothing before and not much since has satisfied me as much as the Quads. I had to give them up when moving to a sum-what smaller living space. Now back to a larger listening environment, Finding a good buy on a pair of Maggie 1.7s, I decided to give them a try to see if they had any of the magic of the Quads. To me, the magic is back, plus, being able to utilize  more power, they are more dynamic than the older model Quads. I do love the 1.7s and have heard good things about the smaller .7s....Jim
Though I have always lusted for Quad's and Maggie's, I never had the money nor the space. But, I have to second the opinions of jhills and herveman. Newer models have less of the problems, especially impedance-wise, that old models have. 
If you are willing to put up with this, then by all means go for it, but in my honest opinion, the technology has improved so much that I think it will be an exercise in frustration. 
B
While I definitely stand up for the Quad ESL57, in no way do I think the speaker remains without flaw.  Despite the pride and territoriality folks exhibit in these forums, ALL audio components have weaknesses, and ALL are flawed.  No product works for everyone, or leaves even the majority feeling satisfied to the point of never considering its potential replacement.  Folks have listed he shortcomings of this product for decades, though I feel apart from the absolute lack of the bottom octave, they often outgrow reality or truth.

In the end, I think Quad's Peter Walker himself said it best when asked if he felt satisfied with his product, "Oh no, we think our loudspeaker very poor, but we think that the others are even poorer!"
Haha...
Well, said.
B
Wow! I never thought my little thread would get so much mileage! I'm impressed. It's a testimony to the impact the Quad speakers had on HiFi. 

I got my Quad 303, 33 and tuner this week. The 33 and tuner beautifully ensconced in a walnut case. I'm not impressed with the quality of the POTS, especially  the tuner with no balanced  flywheel. Still, I think they're very sexy looking. But.. Just to touch a bit of history! 

I shot my wad buying my Bob Latino amps and Quad electronics. No money right now for ESLs. In the couple months I need to recoup my monies I'll have time to think whether I really want the 57s or maybe something newer.

Maybe I should start a Go Fund Me account to see who will donate some money to me so I can compete my passion! Music, HiFi, sex drugs rock and roll! (Just kidding about the drugs!). Anybody want to donate towards a pair of Quads for poor little me, I got a PayPal account! I'll be your new best friend!!! In the meantime I need to sell my 2002 BMW 1150R motorcycle to help pay off this stuff. 

Regards, Mark