Armstrong Audio, originally called Armstrong Wireless and Television Ltd. was a British manufacturer of radios and other audio equipment based in London, England. Founded by Claude Charles Jackson in 1932. History Initially created to manufacture portable radios, during World War II their factory was used to manufacture radios, public address systems, and various electronic parts. After the war, they began to produce television sets, as well as long range radios for ships, but eventually ceased production of those lines to manufacture radios, amplifiers and tuners for home consumer use. In the 1950s when the high fidelity market began to take shape, the company name was changed to Armstrong Audio and they focused their marketing and manufacturing at becoming hi-fi specialists. During the 1960s and 1970s they were extremely successful, creating several durable radio models which are still in use by consumers today, but by the end of the 1970s their lease on their factory ran out and it was decided not to invest in a new one. The building was torn down and the owners redeveloped it. Using plans developed for a further radio model, some of the staff continued on as Armstrong Amplifiers, but due to a lack of capital and suitable manufacturing space, production did not last long. Today, what once was Armstrong Audio is now called Armstrong Hi-Fi and Video Services and is based in Walthamstow, and they provide maintenance contract to a number of retail stores. Armstrong 521 The Armstrong 521 was a stereo hi-fi amplifier from the Armstrong Audio company and was marketed as 2 x 25W amplifier. It employed germanium AL102 transistors in its output stages and these had a reputation for failure and are now unobtainable although it is possible, with modification to replace these with newer, silicon transistors. The amplifier was a single rail design and employed an electrolytic output capacitor in the output stage. The amplifier featured inputs for tape, tuner and MM gramophone and on the front panel had 4 rotary controls for volume, bass, treble and balance. Underneath these controls were a series of black push buttons which allowed control of the input sources as well as loudness, high pass filters, rumble filters and tape bypass. The amplifier was presented with an aluminium, silk-screened front panel with a teak case and a matte black rear panel. The amplifiers were marketed from the 1968–1972 when it was replaced by 600