QUAD 99 Series manual The closest approach

– Noel Keywood, Hi-Fi World

“It is so much better in terms of high fidelity, in its purest sense. It reminded me how Quad retain an almost unique grip on the concept.”

The closest approach...

Since Peter Walker formed the company in 1936, all Quad products have displayed an originality in design, born from a full and proper understanding of every aspect of sound reproduction. A world leader in audio amplifier and electrostatic speaker design, Quad has, over the years, made a major contribution to the improvement of

sound quality. This contribution has been recognised by awards from around the world including the Queen’s Award for Technological Achievement in 1978.

Quad owners enjoy the confidence of knowing that the complete system has been engineered to achieve optimal performance, free from compatibility problems.

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. 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 to the

loudspeakers of the time, the ESL was free of unwanted colourations and distortions. This product remained in production, virtually unchanged, for 28 years.

A decade later 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 prestigious 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.

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.

These are just some of the highlights from Quad’s pedigree line of technological achievement. However, it must always be remembered that Quad has never indulged in technical ‘one-upmanship’. The technology is there for a purpose – and that purpose has remained constant over the years. To reproduce music in a form that is the closest approach to the original sound.

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