'Audio Amateur'
Interviews Peter Walker at the Quad Factory in 1978
TAA: What do you consider to be the important goals of a good audio reproduction system what ought a good audio reproduction system do?
PW: Well, perhaps this reflects my age (62 at the time of the interview), but I am still in favour of documentary type reproduction - an orchestra plays on a stage
… Read MoreClick the images below (l to r) in succession to see Walker's address to the U.K. Audio Engineering Society in 1979 on the Quad ESL 63
Read More ACOUSTICAL MANUFACTURING's Mike Albinson, co-designer of the revolutionary Quad 405 power amplifier, and outspoken critic of many current fashionable amplifier theories, is our subject this month.
Practical Hi-Fi: The Quad 405 represents something fairly unique in modern Hi-Fi amplifier design. What led you to the concept of feed-forward instead of the more normal feedback?
Mike Albinson: Difficult question, but I have a stock answer to
… Read MoreThe Quad Electrostatic Speaker
by Ralph West
The recent appearance of a full range ESL designed and produced by a well-known manufacturer specialising in high quality reproduction, was bound to cause considerable comment and speculation. This speaker, the "Quad" electrostatic, is now in production, and we are pleased to present our readers with a full review of a specimen drawn from current production. The makers
… Read More No, Quad have not capped off their recent release of the ESL 63 speaker with a new amplifier! The 410 is in fact the designation given to the 405 power amplifier when its channels are bridged together to give a mono amplifier of effectively 180 watts. In fact, it is even possible to bridge a pair of these 410 amplifiers to give a mono amplifier
The AUDIO-CRITIC Volume 2, Number 3 (Spring to Fall 1980) wrote:
QUAD ELECTROSTATIC LOUDSPEAKER
"This all-time classic needs no introduction to any audiophile who knows enough to read equipment reviews at all. It has survived virtually unchanged for a quarter of a century (the manufacturer claims there have been no changes whatsoever, large or small, but we take that with a grain of salt); we,
… Read MoreSound Practices - 1994
The Quad Electrostatic Loudspeaker
by Haden Boardman / Mellotone Acoustics
A good electrostatic has something special, a magic spell that weaves itself over you. Critics (of which there are few) moan on ~bout "won't play rock" or "only for string quartets". Ask these plaintiffs what system they have, or what kind of speakers, and the usual response is some old west coast monster.
… Read MoreHi-Fi News and Record Review, UK.
Classic Hi-Fi, Jun 1996
Restoration Drama by Ken Kessler
In late 1995, the Bugatti Owners' Club produced facsimile reprints of all of the issues of the Club Magazine, Buganacs, issued before WWII. It was telling to read articles from, say, 1938, about the trials and tribulations of working on even 10 year old vehicles, at a time when the
… Read MoreThe Quadfather
In the beginning, there was the Quad ESL, the world's first full-range electrostatic loudspeaker.
An appreciation, by Chris Beeching
Quad ESL loudspeaker: available used for between $600 and $2000 per pair and up, depending on condition. Originally manufactured by Quad Electroacoustics, Huntington, England.Surely the venerable Quad speaker is one of the most enduring of all quality hi-fi products ever made.Since it took the
… Read MoreQuad ESLs:Then and Now
Blair Roger
Can a loudspeaker be all things to all people? Probably not, but the Quads take a damn good shot at it and I'll dispute anyone who says otherwise.
Genesis
Peter Walker and his engineering team have been unconventional and pragmatic thinkers since S. P. Fidelity Sound Systems was founded in 1936. By 1938 they were manufacturing a portable public
… Read More The history of this amp's circuit starts twenty five years ago when Julius Futterman, understanding the limitations of the output transformers. patented an Output Transformerless design. The clarity of the sound has been unsurpassed to this day and a cadre of serious music listeners has remained steadfast to the genius of Julius Futterman. The man was the embodiment of integrity in the audio world and
Letter to the Editor
(Julius Futterman)
"I am pleased with your evaluation of the sonic virtues of the H-3aa power amplifier but do take exception to two of your assertions :
The power tubes I use (6LF6) are being manufactured in the USA by GE and Sylvania. They are also being made in Japan and Yugoslavia. I have been informed that they will be around for
… Read MoreGang of Five
Gary Jacobson
N.B. This article is about 10 years old. Therefore an historical document!
Any advice and observations that it contains should therefore NOT be taken as being, in any way current.
Introduction
Madness strikes at all hours of the day and night, so I can’t tell you exactly when it occurred to me to assemble a collection of treble panels from
… Read MoreFiled: November 28, 1921
U.S. Patent 1,550,381
Granted: August 18, 1925
Joseph Masolle, Hans Vogt and Josef Engl assignors to Tri-Ergon Ltd., of Zurich, Switzerland
"Electrostatic Telephone"
Referenced by Walker and Williamson in
U.S. Pat. 3,008,014.
Filed: May 2, 1925
U.S. Patent 1,622,039
Granted: March 22, 1927
Frederick W. Lee, Owing Mills, Maryland.
"Apparatus for and Method of Reproducing Sound".
Referenced by Walker and Williamson in U.S. Pats. 3,008,013 & 3,008,014.
Filed: February 12, 1926
U.S. Patent 1,631,583
Granted: June 7, 1927
John Depew, of New York.
"Capacitatively Actuated Loudspeaker".
Referenced by Walker and Williamson in U.S. Pat. 3,008,014
Filed: March 24, 1926
U.S. Patent 1,674,683
Granted: June 26, 1928
Walter Hahnemann, Kitzberg, Germany, assigned rights to Lorenz Aktiengesellschaft.
"Arrangement for Uniform Electrical Sound Transmission".
Referenced by Walker and Williamson in U.S. Pat. 3,008,013
Filed: June 6, 1928
U.S. Patent 1,762,981
Granted: June 10, 1930
Ralph V.L. Hartley of South Orange, N.J. assigned rights to Bell Telephone Labs., N.Y.
"Acoustic Device"
Referenced by Walker and Williamson in U.S. Pats. 3,008,013 & 3,008,014
Filed: Sept. 27, 1929
G.B. Patent 346,646
Granted: April 16, 1931
Edward Washburn Kellogg, Schenectady, N.Y. assigned rights to General Electric Co. N.Y.
"Production of Sound"
Indirectly Referenced by Walker and Williamson in U.S. Pats. 3,008,013
Filed: February 12, 1930
G.B. Patent 348,573
Granted: May 12, 1931
Albert Rauser and Wilhelm Steuer, of Kottbuser-Ufer 39/40, Berlin, S.O. 26
"Improvements Relating to Electrostatic Loud-speakers".
Referenced by Walker and Williamson in U.S. Pat. 3,008,014
Filed: June 1, 1931
G.B. Patent 370,248
Granted: April 7, 1932
Albert Rauser and Wilhelm Steuer, of Kottbuser-Ufer 39/40, Berlin, S.O. 26
"Improvements in Electrostatic Loud-speakers".
Referenced by Walker and Williamson in U.S. Pat. 3,008,014
Filed: Sept. 8, 1930
G.B. Patent 372,649
Granted: May 12, 1932
Hans Vogt, Genthinerstrasse 17, Berlin, W. 35, Germany.
"Improvements Relating to the Insulation of Fixed Electrodes of Electrostatic Loudspeakers"
Indirectly Referenced by Walker and Williamson in U.S. Pat. 3,008,014
Filed: Sept. 15, 1928
U.S. Patent 1,881,107
Granted: Oct. 4, 1932
Hans Vogt of Berlin-Wilmersdorf, Germany.
"Sounding Condenser"
Referenced by Walker and Williamson in U.S. Pat. 3,008,013. Also ref: GB Patent 322,744 with 17 claims, granted December 10, 1929
Filed: July 30, 1930
U.S. Patent 1,930,518
Granted: October 17, 1933
Jurjen S. High of Camden, N.J. assigned rights to Westinghouse Electric and Manufacturing Co. Pennsylvania.
"Electrostatic Loudspeaker"
Referenced by Walker and Williamson in U.S. Pats. 3,008,013 & 3,008,014
Filed: Sept. 27, 1929
U.S. Patent 1,983,377
Granted: December 4, 1934
Edward Washburn Kellogg, Schenectady, N.Y. assigned rights to General Electric Co., N.Y.
"Production of Sound"
Referenced by Walker and Williamson in U.S. Pat. 3,008,013. Also ref: GB Patent 346,646 which pre-dates this grant of patent on the same device.
See prior citation of E.W. Kellogg.
Read MoreFiled: April 9, 1946
G.B. Patent 610,297
Granted: Oct. 13, 1948
Etablissements S.M. Body Corporate of 26 Rue de Lagny, Paris.
"Improvements in Electrostatic Microphones and Loud-speakers"
Referenced by Walker and Williamson in U.S. Pat. 3,008,013.
Filed: October 5, 1949
U.S. Patent 2,631,196
Granted: October 5, 1953
Arthur A. Janszen, Cambridge, Mass.
"Electrostatic Loud-Speaker"
Referenced by Walker and Williamson in U.S. Pats. 3,008,013 & 3,008,014.
Filed: December 12, 1951
U.S. Patent 2,796,467
Granted: June 18, 1957
Winston E. Kock, Basking Ridge, N.J., assigned rights to Bell Telephone Labs., N.Y.
"Directional Transducer"
Referenced by Walker and Williamson in U.S. Pats. 3,008,013 & 3,008,014.
Filed: December 11, 1953
U.S. Patent 2,855,467
Granted: October 7, 1958
Paul Curry, New Haven, Connecticut assigned rights to Curry Electronics Inc., New Haven, Conn.
"Loudspeakers"
Referenced by Walker and Williamson in U.S. Pat. 3,008,014.
Filed: November 29, 1954
U.S. Patent 2,864,899
Granted: December 16, 1958
Henry W. Parker, Flushing, N.Y.
"Transducer"
Referenced by Walker and Williamson in U.S. Pat. 3,008,014.
Filed: July 15, 1955
U.S. Patent 3,008,013
Granted: November 7, 1961
David Theodore Nelson Williamson, Edinburgh, Scotland assigned rights to Ferranti Ltd., London. Peter James Walker of Huntingdon, England.
"Electrostatic Loudspeakers"
Filed: September 12, 1957
U.S. Patent 3,008,014
Granted: November 7, 1961
David Theodore Nelson Williamson, Edinburgh, Scotland assigned rights to Ferranti Ltd., London. Peter James Walker of Huntingdon, England.
"Electrostatic Loudspeakers"
Filed: September 27, 1929
U.S. Patent 1,983,377
Granted: December 4, 1934
Edward W. Kellogg "Production of Sound"
Referenced by Walker in U.S. Pat. 3,773,984.
Filed: February 21, 1940
G.B. Patent 537,931
Granted: July 14, 1941
Donovan Ernest Lea Shorter
"Improvements in Electrostatic Loudspeakers"
Referenced by Walker U.S. Pats. 3,773,984.
Filed: January 28, 1941
U.S. Patent 2,302,493
Granted: November 17, 1942
Robert B. Dome, Bridgeport, Connecticut
"Amplifying System".
Referenced by Walker in U.S. Pat. 3,773,984.
Filed: June 24, 1943
U.S. Patent 2,387,845
Granted: October 30, 1945
William R. Harry, Summit, New Jersey
"Electroacoustic Transducer".
Referenced by Walker U.S. Pat. 3,773,984.
Filed: December 18, 1948
U.S. Patent 2,634,335
Granted: April 7, 1953
Myron B. Stolaroff, Redwood City, California assignor to Ampex Corporation
"Magnetic Recording System with Negative Feedback System."
Referenced by Walker U.S. Pat. 3,773,984.
Filed: May 19, 1954
U.S. Patent 2,843,671
Granted: July 15, 1958
Charles A. Wilkins and Herbert Sullivan, New York
"Feed Back Amplifiers"
Referenced by Walker in U.S. Pats. 3,773,984
Filed: August 29, 1956
U.S. Patent 2,905,761
Granted: September 22, 1959
Charles A. Wilkins, New York.
"Control of Amplifier Source Resistance"
Filed: September 9, 1958
U.S. Patent 3,061,675
Granted: October 30, 1962
James Ross Macdonald
"Loudspeaker Improvement"
[Claims 1-5], [Claim 5 ]. Diagrams:[Sheet 1] [Sheet 2]
Referenced by Walker in U.S. Pat. 3,773,984.
Filed: December 10, 1958
U.S. Patent 3,135,838
Granted: June 2, 1964
William M. Wright, Boston Mass.
"Electrostatic Loudspeaker"
Referenced by Walker in U.S. Pat. 3,773,984.
Filed: May 18, 1967
U.S. Patent 3,542,952
Granted: November 24, 1970
Chien San Wang, Denver, Colorado
"Low Distortion Signal Reproduction Apparatus"
Referenced by Walker in U.S. Pat. 3,773,984.
Filed: November 3, 1970
U.S. Patent 3,773,984
Granted: November 20, 1973
Peter James Walker of Huntingdon, England.
"Electrostatic Loudspeaker with Constant Current Drive"
Filed: September 26, 1952
U.S. Patent 2,751,442
Granted: June 19, 1956
Raymond W. Ketchlidge
"Distortionless Feedback Amplifier"
Referenced by Walker in U.S. Pat. 3,773,984.
Filed: January 10, 1975
U.S. Patent 3,970,953
Granted: July 20, 1976
"Distortion-Free Amplifiers"
Peter James Walker and Michael Peter Albinson
Filed: January 10, 1975
U.S. Patent 3,970,953
Granted: July 20, 1976
"Distortion-Free Amplifiers"
Peter James Walker and Michael Peter Albinson