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Quad II monoblock valve power amplifier, spares/repairs only. Tar seepage from mains transformer noted; briefly play tested. Tung-Sol KT66 valves and original boxes included. Specifications
Audio Inputs: 1
Colour: Lancaster Grey
Features: Class A push-pull,paraphase circuit, cathode-coupled output stage
Number of Channels: 1
Number of Inputs: 1
Power: 15W into 8 ohms
Supported Modes: Mono
Year Manufactured: 1950s
Power Output (W): 15W into 8 ohms
Mains Voltage: 240V
Condition
Good cosmetic condition (see photos). Will require service before use.
Included
Original box for amplifier
A power cable is NOT included.
Restoration
Last professionally serviced by Servicesound in 2015.
One modern electrolytic capacitor replacement fitted during service (visible internally).
Non-original blue terminal/tagboard strip fitted at speaker output — a service modification.
Brand & history
The Quad II was manufactured by The Acoustical Manufacturing Co. Ltd in Huntingdon, England.
Generating expert take…
Quad, the venerable British hi-fi brand, traces its origins to 1936 in London, when engineer Peter J. Walker founded S.P. Fidelity Sound Systems, soon renamed the Acoustical Manufacturing Company. Relocating to Huntingdon in 1941 after wartime bombing, the firm shifted from public address gear to domestic audio amid post-war demand for superior sound reproduction. Walker's pioneering ethos—prioritizing "the closest approach to the original sound"—defined Quad from its early QA12 amplifiers, adopted by the BBC, to the iconic Quad I of 1953.
The brand excels in amplifiers and electrostatic loudspeakers, revolutionizing both categories. The Quad II power amplifier of 1953 introduced cathode coupling for vanishingly low distortion, while the 1956 ESL 57 delivered the world's first full-range electrostatic speaker, employing a massless film diaphragm for unparalleled transparency and transient speed. Quad advanced into solid-state with the 1967 303 and transistor designs featuring innovative "Triples" output stages, later expanding to integrated amps like the 99 series, moving-coil speakers, and modern electrostatic models such as the ESL 988 and 989.
Today, under the International Audio Group since 1997, Quad holds a prestigious position in the high-end market, revered by audiophiles for its unyielding pursuit of accuracy over trends. Its heritage components command vintage collector status, yet contemporary offerings maintain a niche boutique appeal among discerning buyers seeking refined, distortion-free reproduction that honors Walker's legacy.
See all Quad listings on RADAR.
