Integrated Amplifiers

With pairs of Mullard ECC83 and EF86 tubes under its stylish bonnet, Quad’s iconic 22 ‘control unit’ [pictured below] appeared in 1959, shortly after stereo LPs first became available in the UK. The matching mono Quad II power amplifier had been launched some six years earlier, but with the 22 now on the scene [HFN Apr ’60 & Mar ’14], the former was then sold in pairs to form the heart of many an early stereo system, complete with not one but two ESL-57 loudspeakers! This was the Acoustical Manufacturing Company’s only stereo amplifier until 1967 (the company changed its name to Quad Electroacoustics in 1983), when the transistorised 33/303 system [HFN Apr ’68 & Jul ’11] was introduced.

The 22 and II were comprehensively interconnected – AC power and input signals were supplied to the 22 where all the controls were located, while two umbilical cables carried both power and audio to the Quad II amps. These cables were terminated in custom-made flexible plastic boots, colour-coded to differentiate between the two channels – blue for left and yellow for right or mono-only operation. Some 65 years later and today’s fully integrated, digitally equipped, solid-state Quad 3 would surely have been the stuff of fanciful science fiction for those latter-day engineers. PM