In 1920, engineer Stanley R. Mullard started the Mullard Radio Valve Co. Initially located in Southfields, London, Mullard eventually found a need to expand their manufacturing. By 1923, Mullard had partnered with a well known Dutch light bulb manufacturer Philips & Co. who started producing medical X Ray devices by 1918.
Mullard was now producing electronic components for the BBC and Philips products. Four-pin valves produced under the name Philips Mullard by 1925 had the PM3 and PM4 designations (See ad pic).
In 1927, Philips started their own line of valve radios, becoming the world’s largest producer by 1932. In 1927, Philips & Co became sole owner of Mullard Radio Valve and Stanley Mullard later retired in 1930. England declared war with Germany in 1939, increasing the demands for Mullard Radio Valve to produce more valves throughout the war period.
Between 1938 and 1955, Mullard had built six factories in England. By 1962, Mullard Radio Valve had become the largest valve manufacturer in Europe, with its largest factory in Blackburn, England. The Blackburn facility employed over 6,200 people by 1962. Mullard Radio Valve produced their first pentode in 1928 at their Blackburn facility and their famous EL34 in 1953.
By the mid 1950’s, the transistor had begun replacing valves in new electronics. In about 1988, Philips sold the Mullard Brand name to Mike Matthews with the New Sensor Corp. (http://newsensor.com) in New York.