Quad QII-Classic

The Quad QII-Classic is a faithful recreation of one of the most celebrated power amplifiers in the history of high-fidelity audio — a monoblock that carries the spirit, the circuit topology and the extraordinary musicality of Peter Walker's original Quad II directly into the present day. First introduced in 1953, the original Quad II established a standard for valve amplifier design that the finest engineering minds in the industry have spent seven decades analysing, admiring and attempting to surpass. The QII-Classic honours that legacy without compromise — recreating Peter Walker's output transformer design with the precision and reverence it deserves, and equipping it with output and input valves that are the direct equivalent of those used in the amplifier that made Quad's reputation.

Peter Walker's Output Transformer — A Circuit of Legendary Status

The output transformer at the heart of the QII-Classic is the definitive expression of Peter Walker's circuit philosophy — a component whose design has achieved legendary status in the audio engineering community, studied and celebrated as one of the most elegant solutions to the fundamental challenges of valve output stage design ever committed to production. Walker's transformer topology achieves an extraordinary combination of bandwidth, low distortion and dynamic linearity that solid-state designs have long sought to replicate — and which the QII-Classic preserves in its entirety, with output valves operating in Class A to deliver approximately 15 watts per channel of the most gloriously refined and musically coherent amplification available at any price.

Class A Operation — The Foundation of the QII-Classic's Musical Character

Class A operation is the defining characteristic of the QII-Classic's sonic performance — and the quality that most directly connects it to the original Quad II's reputation for sweetness, refinement and effortless musical communication. Operating entirely within the linear region of the output valves' characteristics, the QII-Classic produces vanishingly low crossover distortion and a harmonic structure that is dominated by even-order components — the distortion profile that the human ear finds most musically natural and least fatiguing over extended listening sessions. Fifteen watts of genuine Class A output power is more than sufficient to drive a wide range of contemporary loudspeakers to satisfying levels — and in a well-matched system, the QII-Classic's 15 watts will outperform the subjective loudness and dynamic authority of a much higher-powered solid-state amplifier operating in Class AB.

Fully Monoblock Architecture

The QII-Classic is supplied and used in matched pairs — each monoblock handling a single channel, ensuring that left and right channels remain entirely discrete from input to output, with no possibility of crosstalk, shared power supply interaction or mechanical coupling between channels. This fully monoblock architecture is the most uncompromising approach to stereo amplification available, and in the QII-Classic it is combined with the most revered valve circuit in audio history — a combination of principle and execution that sets a new standard for what a valve power amplifier at this price can achieve.

System Matching

The QII-Classic is the natural partner for the Quad QC 24 valve preamplifier — together recreating the complete Quad II system in its most authentic and musically rewarding form. Those whose loudspeakers demand more power without sacrificing the Class A valve character of the QII-Classic will find the Quad QII-Forty a logical next step, while the Quad QII-Eighty represents the ultimate expression of Quad's valve power amplifier engineering. For those building a complete Quad system, the Quad Revela 1 loudspeaker is an outstanding partner — its sensitivity and impedance characteristics making it ideally suited to the QII-Classic's 15 watts of Class A output.

Buying from Martins Hi-Fi

Martins Hi-Fi has been in Norwich since 1968. Elizabeth Gould runs the business today, and we stock only brands we have heard properly and stand behind. The Quad QII-Classic is available to hear in our Norwich showroom — speak to Dave or Chris to arrange a demonstration with the QC 24 preamplifier and a pair of carefully matched loudspeakers.

Contact us at info@martinshifi.co.uk, call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martins Hi-Fi page. We are at 85–91 Ber Street, Norwich, NR1 3EY.