“Quad has succeeded where few of hi-fi’s gamblers dare: They’ve followed the ESL-989 with not just a worthy amplifier, but with a silent

smooth and precise control unit as well.”

– Ken Kessler, Hi-Fi News

The standard QC-twenty-four is line level only. There is an option of a solid-state phono stage which can be added when new, or at a later stage.

Peter Walker always believed that an amplifier should be as simple as possible - engineer with the fewestpossiblecomponentsandwithaperformance largely independent of those components.

The QC-twenty-four, a low-noise RIAA curve phono stage has an understated elegant simplicity, although we use high quality components wherever these appear in the signal path.

Bifurcated contact relays (crossing each other at right angles to make a better contact) are used on each input to maintain the best possible signal conduction. Gold-plated connectors and a carefully screened enclosure are further examples of the attention to detail throughout the construction.

The total line gain is 15dB, with a high quality potentiometer controlling the output levels. Reminiscent of the original QC-22 control module, there is a simple balance control allowing for variation from left to right of up to 12dB.

Amplification is provided courtesy of a twin triode 6111, new old-stock valve - originally designed for use in the guidance systems of missiles and manufactured to exceptionally high tolerances. The remarkably long expected life- span of this valve means we can comfortably build it into the PCB without the compromises usually experienced when using valve seats. Two buffered tape loops are provided as standard.

Acompletely new design, the QC-twenty-fourpre amplifier is both neutral and detailed. Using a military specification 6111 valve, which is so reliable, it’s hard-wired to the circuit board.

Everything has on this pre amplifier has been designed to maintain optimum signal purity. From

the relay switching to the gold-plated terminals, each component has been selected specifically for its audio performance.

The chassis is painted to match both the Quad II- Classic and the Quad II-fortypower amplifiers, making it the perfect partner to both systems.

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QUAD QUAD II-FORTY manual Ken Kessler, Hi-Fi News
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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.
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