QUAD QUAD II-FORTY manual II-classic

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The Quad

II-classic

This is a faithful reproduction of the original, the new Quad II Classic offers audiophiles the chance to recreate the spirit and atmosphere produced from one of the most famous amplifiers in audio history.

The original Quad II was first launched in 1953, designed by Peter Walker. At the time, many of his contemporaries were also producing good quality valve amplifiers. The Quad II looked, in comparison, very simple and unassuming, but its performance was far beyond that which its diminutive dimensions might suggest.

The property which set the Quad II amplifier apart from other amplifiers of the time was its output stage. It was arranged such that the cathode coupled circuit emulated the performance of triode operation, but with the size and efficiency characteristics of pentode operation. It was this breakthrough that ensured the Quad II was to remain in continuous production until 1970.

Peter’s circuit, notably the design of the output transformer, has become the stuff of legend amongst electronics engineers. Studied and analysed by the finest minds in the industry, the elegance and coherence of the design is still regarded as a reference today.

Given the quite modest components of the day, he was able to engineer something which was quite literally greater than the sum of its parts.

The Quad II classic has been recreated accurately with output valves and input valves the equivalent of those used in the original design. The same balancing act has been employed to ensure the same wealth of detail and gentle tone of the original.

The output valves produce around 15w per channel, operating in Class A which, although slight by modern standards, allows a gloriously sweet and refined sound with appropriately matched contemporary loudspeakers.

‘the closest approach to the original sound...’ has been a Quad philosophy since 1936. More than just a slogan, it underlies the company’s commitment to producing the finest audio equipment, capable of reproducing all the elements and emotion of a live performance.

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Contents Vacuum Tube Amplifier Systems II-forty Ken Kessler, Hi-Fi News II-eighty Page QC-twentyfour Ken Kessler, Hi-Fi News QC-phono stages II-classic 1V RMS

QUAD II-FORTY specifications

The QUAD QUAD II-Forty is a standout integrated amplifier designed for audiophiles seeking premium sound quality without compromising on technology and features. This amplifier exemplifies QUAD's commitment to delivering high-fidelity audio, rooted in decades of engineering excellence.

One of the primary features of the QUAD II-Forty is its Class AB amplifier topology. This innovative design combines the efficiency of Class B with the linearity of Class A, resulting in a robust power output of 40 watts per channel. This ensures rich, detailed sound reproduction across various volumes, making it suitable for both quiet listening sessions and larger gatherings.

The QUAD II-Forty incorporates advanced circuitry, utilizing low negative feedback to maintain audio clarity and prevent distortion. The amplifier is equipped with an ultra-low output impedance that enhances damping factor. This characteristic allows it to drive a variety of speakers with precision, providing tight, controlled bass as well as a lush midrange and sparkling highs.

Integrated within the QUAD II-Forty are innovative technologies such as the enhanced power supply system, which utilizes oversized transformers for improved dynamic response. This results in better transient response, allowing the amplifier to react swiftly to sudden changes in musical content, enhancing the overall listening experience.

Moreover, the QUAD II-Forty features multiple input options, including RCA and XLR connectors, making it versatile enough to accommodate different audio sources, from CD players to vinyl turntables and digital streaming devices. The inclusion of a high-quality phono stage adds further value, allowing users to connect their turntables directly without the need for additional preamps.

The aesthetic design of the QUAD II-Forty also deserves mention. Its classic styling, characterized by a sleek, understated chassis and elegantly placed controls, ensures that it not only performs beautifully but also complements any audio setup.

In summary, the QUAD II-Forty is a remarkable integrated amplifier that embodies QUAD's rich heritage of audio engineering. With its powerful Class AB output, advanced circuitry, versatile connectivity, and elegant design, it is a superb choice for anyone looking to enhance their audio experience. Whether used in a modest home setup or a dedicated listening room, the QUAD II-Forty promises to deliver an unparalleled listening experience that will satisfy even the most discerning audiophiles.