Quad

Peter Walker's electrostatics — the closest approach to the original sound

History

Quad Electroacoustics was founded in London, England in 1936 by Peter Walker as the Acoustical Manufacturing Company. The name "Quad" came from Quality Unit Amplified Domestic—reflecting Walker's goal of creating high-quality audio equipment for home use.

Peter Walker was a true visionary who believed that audio equipment should disappear, leaving only the music. His philosophy was expressed in Quad's slogan: "The closest approach to the original sound."

The Quad II amplifier (1953) established Walker's reputation for innovative tube design. Using a unique "cathode-coupled" output stage, the Quad II delivered 15 watts per channel with exceptionally low distortion. It remained in production for nearly 20 years.

The ESL-57 electrostatic loudspeaker (1957) revolutionized speaker design. Using a thin, charged diaphragm suspended between perforated stators, the ESL-57 eliminated the box coloration and moving mass of conventional speakers. It is widely considered one of the greatest speakers ever made.

The 1980s brought the ESL-63, an improved electrostatic design that addressed some limitations of the original. The 606 and 909 solid-state amplifiers continued Quad's tradition of British engineering excellence.

Today, Quad continues as part of the International Audio Group, still producing electrostatic speakers and amplifiers that honor Peter Walker's legacy.

Key Facts

Legendary Products

Quad ESL-57 (1957-1985)

One of the most important loudspeakers in history. The ESL-57's electrostatic design eliminated box coloration and moving mass, producing a transparency that remains the benchmark for many listeners. In production for 28 years.

Quad II (1953-1970)

A legendary tube amplifier that demonstrated Peter Walker's innovative circuit design. The Quad II's "cathode-coupled" output stage produced just 15 watts per channel but with exceptionally low distortion and beautiful sound.

Quad ESL-63 (1981-1999)

An improved electrostatic speaker that addressed the limited bass and power handling of the ESL-57. The ESL-63 used a segmented diaphragm and delay lines to create a more coherent wavefront.

Quad 303 (1967)

A solid-state power amplifier that brought Quad quality to transistor technology. The 303's "triple-emitter follower" output stage was innovative and reliable, making it popular for professional and home use.

Classic Models Reference

Sound Signature

Quad equipment is characterized by:

• Transparency - Electrostatic clarity
• Low distortion - Peter Walker's obsession
• Musical naturalness - "Closest approach"
• British reserve - No artificial excitement
• Long-term satisfaction - Easy to live with

Collecting Quad

Vintage Quad gear is valued for:

• ESL-57 - The electrostatic icon
• Quad II - Tube amplifier classic
• Matching sets - II/22 or 303/33
• Working ESLs - Panels must be functional
• Original condition - Unmodified preferred

Most collectible models:

• ESL-57 - The holy grail
• Quad II - Tube amplifier legend
• ESL-63 - Improved electrostatic
• 303/33 - Solid-state classic

Restoration Tips

Common Quad service items:

• ESL-57/63: Check panels for arcing (critical)
• ESL-57/63: Replace dust covers
• Tube amps: Replace capacitors
• Verify bias settings (ESL panels)
• Professional ESL service recommended
• Parts available for amplifiers

Competitors & Comparisons

Quad vs ESL designs: Quad invented the category

Quad vs Magneplanar: Different approaches to panel speakers

Quad vs Box speakers: Quad eliminates box coloration

All Models in Archive (18)

Amplifiers, Electrostatic Speakers

• Quad - The Closest Approach

Amplifiers

• 33/303-COMBINATION - 1970
• quad-33
• quad-405 - 1975
• quad-405-2
• quad-44 - 1981
• quad-ii

Receivers

• quad-fm-multiplex-decoder

Speakers

• 44/405-COMBINATION - 1976
• quad-esl-2805 - 1981
• quad-esl-63 - 1981

Tuners

• quad-am - 1971
• quad-am3 - 1971
• quad-amii - 1973
• quad-fm - 1975
• quad-fm2 - 1969
• quad-fm3 - 1975
• quad-fmii - 1970
• quad-hr1 - 1978