Quad

"For The Closest Approach To The Original Sound"

The history of Quad is one of technical achievement in the field of sound reproduction. It is a story that began with the Quad 1 amplifier, which brought the benefits of 15 years knowledge and experience in professional audio and industrial products to the task of making the most accurate domestic audio amplifier of its age.
A few years later, in 1953, the product which set the standard for amplifiers was the Quad II Power Amplifier, the time of Queen Elizabeth's Coronation and the year in which Mount Everest was finally conquered. This amplifier pioneered the principle of cathode coupling through the output transformer to reduce harmonic distortion to almost negligible levels. Such was its clear superiority that this model remained in production for 18 years. Three years later, in 1956, Quad demonstrated the first true full-range electrostatic loudspeaker. This remarkable product (known later as the ESL 57) used a virtually mass-less plastic film as a moving diaphragm between two charged plates. Compared with moving coil loudspeakers, the ESL 57 was free of unwanted colourations and distortions. This landmark product remained in production, virtually unchanged, for 28 years.

In 1967 Quad introduced its first transistorised amplifiers, the 33 Control Unit and the 303 power amplifier. These amplifiers introduced a new 'Triples' output stage that solved all the thermal instability problems that plagued early transistor designs. Radical in both circuit design and appearance, they went on to win a Design Council Award in 1969.
Amplifier performance took a further step forward in 1975 with the arrival of the Quad 405 'Current Dumping' amplifier. This remarkable new circuit topology remains one of the few truly original amplifier designs and has featured in Quad products ever since. For this technology Quad was awarded the Queen's Award for Technological Achievement in 1978. Numerous other prestigious awards were presented to Quad from all over the world. In 1981 Quad announced the ESL 63; a full-range electrostatic loudspeaker based upon two sets of concentric annular electrodes fed through sequential. delay lines. This patented system produces a sound pressure pattern identical to the theoretical ideal of a point source origin. Once again a Quad electrostatic loudspeaker became the reference standard around the world.

Audiolab

The history of Quad is one of technical achievement in the field of sound reproduction. It is a story that began with the Quad 1 amplifier, which brought the benefits of 15 years knowledge and experience in professional audio and industrial products to the task of making the most accurate domestic audio amplifier of its age.
A few years later, in 1953, the product which set the standard for amplifiers was the Quad II Power Amplifier, the time of Queen Elizabeth's Coronation and the year in which Mount Everest was finally conquered. This amplifier pioneered the principle of cathode coupling through the output transformer to reduce harmonic distortion to almost negligible levels. Such was its clear superiority that this model remained in production for 18 years. Three years later, in 1956, Quad demonstrated the first true full-range electrostatic loudspeaker. This remarkable product (known later as the ESL 57) used a virtually mass-less plastic film as a moving diaphragm between two charged plates. Compared with moving coil loudspeakers, the ESL 57 was free of unwanted colourations and distortions. This landmark product remained in production, virtually unchanged, for 28 years.