Quad ESL-57

Download the Quad ESL-57 brochure
Download the Quad ESL-57 schematic
Download the Quad ESL-57 owners manual
Download the Quad ESL-57 service manual


General information[contribute]

The Quad ESL-57 is an electrostatic speaker. It was manufactured from 1957 to 1985.

Quad ESL 57 electrostatic loudspeaker. 54.000 units sold

Absolutely Great News

Rob Flain (November 2001): We are now fully servicing the 57's again and have sources for most of the parts.

Very Funny News

Joerg Baar (March 2001): Today I surfed through a tour an US-american engineer took to the Martin Logan plant. It was very interesting, there were a lot of pictures and texts about the development. Guess what ESL was in the reference-listening room. Right there stood a pair of the QUAD 57, direkt next to a Martin Logan speaker. You can find a picture of it in the pictures section.

Wonderful News

Christian Steingruber (March 2000): UK magazine Hifi-News and Record Review just finished its series about classic products with "The Greatest hi-fi design of all time - the Quad ESL 57" Ken Kessler says " We are concluding our millennial series in the only possible way - by revealing what we believe to be the greatest product of all time " The report contains an interesting interview with Peter Walker, taken in 1994, and some most interesting information about the Quad activities under the new owner, Stan Curtis. Concluding the writer, Mr.Kessler, argues that the revitalized Quad company should produce a contemporary version of the ESL-57. He argues that he and thousands of enthusiasts will buy a pair immediately.

The new mono valve amps should be ready for the market as well as the new 988 and 989 electrostatics. Some further information is about a new subwoofer by the Gradient, dedicated for ESL 57. A special OTL amplifier by Tim de Paravicini is mentioned that used to be mounted inside the Quads. Unfortunately I cannot find any hints about this product in the EAR site , but you may try too. http://www.ear-yoshino.com

Christian Steingruber (March 2000): Not only Mark Levinson tried to create super-Quads with his HQD-system, but also Mr.Robertson-Aikman of SME, the famous British tone arm maker. His first Quad system consisted of three ESL 57 speakers per channel (stacked), but with the treble units doubled. Thus the whole system consisted of 12 treble units and 12 bass units (!). Later on Mr.Robertson-Aikman changed over to ESL 63. As the delay line of the ESL 63 did not work properly with stacked pairs, he took a different approach with 2 speakers angled at 90 degrees. Hifi-Choice reported about both systems.

John Hamm (December 2000) ESS, Levinson and David Beatty used the Quad ESL as midrange units. ESS in the SuperQuad system, Levinson in the HQD system and David Beatty in their version of the Stacked system. Regrettably ESS and David Beatty are no more. Levinson is still in business but do not as I know support the Quad speakers.

John Hamm (Decembver 2000) I've owned a pair of the David Beatty version of stacked-Quads. These were stacked top to bottom rather than bottom to bottom of the Levinson HQD version. The horizontal wooden bar is designed to be at, approximately, ear level. Positioning of the Quad ESL is extremely difficult and time consuming and critical! I've driven this pair off a number of amplifiers. Heath, Sony TA-3200F (in series not parallel) and a GAS Son of Ampzilla.

The Quad ESL The Quad ESL is a site dedicated to the original Quad electrostatic loudspeaker. It also has a patent history section for the ESL 63. Repair, Parts, History, Mathematics, Panel Coatings, Original Panel Structure Schematics, and all cross referenced to patent information published by Williamson and Walker. (by Gary Jacobson)(July 2000)
SDS Labs Page A very informative site on -among a lot of other stuff - refurbishing Quad ESL57's and information on the Quad ESL 63

James Wong (May 29, 2005): Here is a list with all serial numbers of the Quad ESL 57 and their year of manufacture:

1958 1 - 2000
1959 2000 - 4000
1960 4000 - 6000
1961 6000 - 8000
1962 8000 - 10000
1963 10000 - 12000
1964 12000 - 14000
1965 14000 - 16000
1966 16000 - 18000
1967 18000 - 20000
1968 20000 - 22000
1969 22000 - 24000
1970 24000 - 26000
1971 26000 - 28000
1972 28000 - 30000
1973 30000 - 32000
1974 32000 - 35000
1975 35000 - 38500
1976 38500 - 41000
1977 41000 - 44000
1978 44000 - 47400
1979 47400 - 50300
1980 50300 - 52100
1981 52100 - 52800
1982 52800 - 53000
1983 53000 - 53150
1984 53150 -

Steve (July 14, 2011): The full range electrostatic, the ESL-57, was first demonstrated in London to an invited group of leading audio engineers in 1956, and went into production in 1957. This was the result of a long-existing appreciation for the benefits of the electrostatic principle and concentrated, day and night research of materials and techniques, all under strict secrecy by Quad in Huntingdon.

Although the electrostatic principle has long been seen as the solution to problems in loudspeaker development, the early problems in materials such as intestines of animals for the membranes and the difficulties in dealing with very high voltages in equipment for home use, were so great that this principle seemed impossible. With the introduction of the dynamic speaker, the electrostatic principle was banned. However, as soon as the development of a suitable material for light membrases was introducsed, it was possible to fabricate electrostatic loudspeakers.

The fact that the ESL-57 production remained unchanged for 28 years was a great victory for those who spend time designing and developing this loudspeaker and a confirmation that they were many years ahead. It became the standard to which all other devices were tested. Braun, Germany was the first foreign company that produced the speaker under license, followed by KLH and Acoustech in the U.S..


One Thing Audio
One Thing Audio Replacement Panels and
Electronics for the Quad ESL's


Joerg Baar, ESL-57 Restauration (PDF article) (Provided by Joerg Baar, May 2002)
Spare parts needed to refurbish the ESL 57 and ESL 63
Chris Beeching, The Essential ESL
Haden Boardman, The Quad Electrostatic Loudspeaker
Peter Kant ESL repair

Repairing a treble panel by Jon Mechling
Sheldon D. Stokes, Refurbishing the Quad ESL 57
Stewart Penketh' step by step repair guide
Ageing Quad Panels, How Old is Old? by Gary Jacobson)
The Original Quad Diaphragm Coating by Gary jacobson

Andy's HiFi and Music Website, guides to refurbish the Quad ESL 57 (external website)
American Graphite, Classic Hifi December 1997 (by Stuart Perry and Andrew King) (Christian Steingruber, April 2002)
Back to Bass-ics, Classic Hifi June 1998 (by Stuart Perry and Andrew King) (Christian Steingruber, April 2002)


Classique Sounds Classique Sounds who sell parts for the Quad ESL 57. They also repair the ESL 57 for you.
One Thing Audio One Thing Audio provides replacement panels for both 57's and 63's.
Peter Kant ESL repair (Christian Steingruber, December 2000)
Quad Musicwiedergabe GmbH They sell all the parts for the Quad ESL 57 and other Quad parts. They obtained the original Quad stretching jig for assembling the panels. Nice catalog on request.
Sheldon D. Stokes (external website)Refurbishing the Quad ESL 57

Stewart Penketh' Repair service for ESL 57 panels (Stewart Penketh, January 2002)
QS & D , Specialised in repairing the Quad ESL 57 and ESL 63
Wayne Picquet's Refurbishing Service
Quad ESL 57 repair ESL-Labs provides refurbished original Quad parts. Panels are build on a copy of the original stretching jig.



Haden Boardman"s modified looks (Haden Boardman, March 2005)
Modifying the EHT supply (Anders Enquist)
Wayne Piquet"s modified looks (Wayne Piquet, March 2002)
Gregor Zielinsky, two modified installations (Gregor Zielinsky, April 2004)
Tim Andrew, fabric grille (Tim Andrew, June 2004)


Arcici stands
Gradient Subwoofer SW-57


Chris Beeching, Stacked Quads and other Mods
My friend Demis" Stacked Quads (David Dlugos, December 2000)
Wayne Piquet"s stacked Quads (Wayne Piquet, September 2001)
Double Quad, A step closer to the ultimate sound (PDF article) (by Dr. T. Farrimond"s, Electronics Today International, Feb 1975)


Peter D. O"Neill"s Home Theatre System
Stewart Penketh Home Theatre System

Other manufacturers using the Quad ESL 57

Other manufacturers using the Quad ESL 57


ESL 57, Amplifiers with the Quad ESL 57
ESL 57, The Amplifier Matter, Sixth edition by Christian Steingruber, MAES
The Good, the Bad and the Ugly by Christian Steingruber
Review of treble panel build by Wayne Picquet. A review by Gary jacobson
The Original Quad Diaphragm Coating, A Review by Ben Openshaw

Forum topics on the Quad ESL-57

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