The Quad

II-eighty

The Latest addition to the Quad Valve Power amplifier series is the long-awaited Quad II-eighty amplifier. The perfect partner to our latest ESL speakers, the II-eighty is not merely a nod in the direction of retro styling, it’s a modern high-performance amplifier designed by one of the most famous tube-amplifier designers in the world (Tim De Paravicini) using more than a little inspiration from the original Quad II amplifier.

The Quad ll-80 is an 80 watt mono power amplifier following in the tradition and philosophies of Peter Walker. The output section consists of 4 KT88 valves running as two pairs in push pull with the hallmark Quad topology of partial cathode loading in the output transformer.

This method reduces distortion when compared to the usual Ultra Linear or triode methods, however, it does require a greater grid driving voltage. This is achieved, again in true Quad fashion, using a balanced pair input stage.

The output transformer has been designed to improve high frequency performance and accurately balance the two push pull halves. Also the transformer has been designed to make sure that full output is realised at the bass frequencies down to 20 Hz.

Each output valve has its own cathode resistors to provide reliability and self-matching. The screen grids of the KT88 valves are run from a lower voltage, again for good reliability. The whole amplifier has a total of only 16 dB of feed-back providing good stability into virtually any known loudspeaker and especially the famed Quad electrostatic loudspeakers.

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QUAD QUAD II-FORTY manual II-eighty

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.