M-OV (Marconi-Osram Valve Company) was a British manufacturer of

thermionic valves A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a ...

(vacuum tubes). It was a subsidiary of the (British) General Electric Company Ltd. The company was founded in 1919, when the valve making interests of GEC (Osram) and the

Marconi Company The Marconi Company was a British telecommunications and engineering company that did business under that name from 1963 to 1987. Its roots were in the Wireless Telegraph & Signal Company founded by Italian inventor Guglielmo Marconi in 1897 ...

were combined. In 1929, Marconi sold its interest in the company to the

Gramophone Company The Gramophone Company Limited (The Gramophone Co. Ltd.), based in the United Kingdom and founded by Emil Berliner, was one of the early recording companies, the parent organisation for the ''His Master's Voice (HMV)'' label, and the European ...

, a predecessor of

EMI EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British transnational conglomerate founded in March 1931 in London. At the time of its break-up in 201 ...

. In 1939, M-OV acquired two disused cotton mills at Shaw, Oldham where it established a

shadow factory A shadow is a dark area where light from a light source is blocked by an opaque object. It occupies all of the three-dimensional volume behind an object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, o ...

to produce valves and cathode ray tubes. The two mills named Cape and Duke, were bought from the

Lancashire Cotton Corporation The Lancashire Cotton Corporation was a company set up by the Bank of England in 1929, to rescue the Lancashire spinning industry by means of horizontal rationalisation. In merged 105 companies, ending up in 1950 with 53 operating mills. It wa ...

for £7,000. Cape mill was used as the main production facility at Shaw, with the adjacent Duke mill remaining mostly unused. Shaw produced a vast array of valves for the war effort, some of which are listed below. * VT104 and VT105 for the

T1154 The R1155 was a British communications receiver, commonly used in aircraft along with its associated T1154 transmitter. It was used extensively by the Royal Air Force during World War II, mainly in larger aircraft such as the Avro Lancaster, Han ...

transmitter. * VR99, VR100, VR101 and VR103 for the

R1155 The R1155 was a British communications receiver, commonly used in aircraft along with its associated T1154 transmitter. It was used extensively by the Royal Air Force during World War II, mainly in larger aircraft such as the Avro Lancaster, Han ...

receiver. * TT11 for the TR1143 fighter set. * VT90

micropup In electronics, a micropup is a style of triode vacuum tube (valve) developed during World War II for use at very high frequencies such as those used in radar. They are characterized by an external anode block, which allows better heat dissipation. ...

used in airborne radar. EMI sold its share of M-OV to GEC in 1956. The company continued to manufacture valves at the Brook Green Works, Hammersmith, London, until 1988. M-OV branded

new old stock New old stock (NOS), or old stock for short, refers to aged stock of merchandise that was never sold to a customer and still new in original packaging. Such merchandise may not be manufactured anymore, and the new old stock may represent the only ...

valves, continue to be highly prized by enthusiasts of the

valve sound Tube sound (or valve sound) is the characteristic sound associated with a vacuum tube amplifier (valve amplifier in British English), a vacuum tube-based audio amplifier. At first, the concept of ''tube sound'' did not exist, because practically ...

. Notable products of the company included

cathode ray tube A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms ( oscilloscope), pictu ...

s for television, starting in the 1930s. The company also introduced the

KT66 KT66 is the designator for a beam power tube introduced by Marconi-Osram Valve Co. Ltd. (M-OV) of Britain in 1937 and marketed for application as a power amplifier for audio frequencies and driver for radio frequencies.Editors "The New Valves" ''W ...

"kinkless tetrode" (beam power tetrode). In 1922 the company brought out valves using thoriated tungsten filaments, which needed less battery power to operate than former types. During World War II the company developed the CV122 valve used in the

proximity fuse A proximity fuze (or fuse) is a Fuze (munitions), fuze that detonates an Explosive material, explosive device automatically when the distance to the target becomes smaller than a predetermined value. Proximity fuzes are designed for targets such ...

Bibliography

* Barry Vyse & George Robert Jessop, ''The Saga of Marconi-Osram Valve: A History of Valve-making at One of the World's Foremost Enterprises'', Vyse Ltd, 2000

External links

* http://www.gracesguide.co.uk/Marconi-Osram_Valve_Co Electronics companies of the United Kingdom General Electric Company Electronics industry in London Defunct technology companies of the United Kingdom Electronics companies established in 1919 1919 establishments in England {{electronics-stub