II Forty

About the II Forty

The Quad II-Forty is a modern **monoblock valve power amplifier** derived from the legendary Quad II amplifier designed by Peter Walker, founder of Quad. It increases continuous power output from the original II’s 15W to **40W RMS into 8Ω**, while preserving the elegantly simple circuit concept of the classic design. The II-Forty employs **KT88 output valves in push-pull Class AB configuration**, military-grade **6SH7 input valves**, and a **5U4G rectifier** in a more robust power supply, delivering higher current capability for contemporary loudspeakers, including Quad ESL models. The chassis is enlarged relative to the original Quad II to accommodate substantially larger, hand‑wired components, including newly engineered mains and output transformers, and offers 4Ω and 8Ω loudspeaker taps. Sonically, the amplifier is described as fast, crisp and detailed yet delicately balanced, providing refined, powerful performance in the modern sense while remaining visually and conceptually faithful to the 1950s original. The II-Forty is sold as a **matched pair of monoblocks** and has been produced in small batches for the Quad Classic Tube Series, making it a sought‑after choice among valve enthusiasts and analogue music listeners.