The Acoustical Manufacturing Company was founded by Peter Walker in London in 1936. In 1941 the factory was moved to Huntingdon after the London factory was bombed.
Initially the Acoustical Manufacturing Company produced PA amps, but soon the move to the production of domestic hifi equipment was made. This led to the acronym Quality Unit Amplified Domestic. Many fine and revolutionary amps and radios were produced. Some schematics of the tubed equipment can be found below.
Peter Walker passed away december 10th 2003 at the age of 87.
AM2 AM Radio
FM16 FM Radio
22 Pre amplifier
Schematic redrawn by Keith Snook.
II Power amplifier
II-40 Power amplifier
If you want to know what QUAD is up to today have a look at the UK site.