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Posted by STEVE M on

We now pick up our story of Mullard in 1939. Well by February 1939, the fledgeling Mullard Blackburn factory was working of sorts with just 38 staff and by June they were firmly entrenched in the manufacture of domestic receivers, components and lamp filaments.

SS Eriks, mindful of the voracious demand for valves pressed ahead and by the end of 1939 a second building had been erected at Blackburn to allow valve making to commence with manufacturing instrumentation and equipment hurriedly shipped from Eindhoven in Holland. The idea was that Blackburn would commence pilot manufacture of the new EF50 valve, introduced in Holland in early 1939 principally for television receiver use. 

Like it's contemporary, the Acorn valve, the EF50 was very different from any valve Mullard had manufactured previously. It needed a skilled labour force, new equipment and instrumentation and the consistent application of hitherto unknown manufacturing techniques because in the EF50, the traditional micanol base was replaced with a 'disc seal' glass base which required, special manufacturing equipment, special glass and three types of special wire!!!!! 

Early attempts at base manufacture were catastrophic, mindful of waste, the winds of war circulating Europe and the shame of being looked down on by Philips management, Dr E A Roberts of Mullard Blackburn was seconded to the Emmasingel development laboratories of Philips Eindhoven in February 1940 to perfect the required glass forming techniques.

In May 1940, as the Panzer tanks rolled into Holland, the good Doctor made good his escape from Holland by hitching a lift on a passing British destroyer. Thankfully, he carried a briefcase stuffed full of drawings, formulae and information on glass forming but more importantly, he had helped broker a deal with Philips Eindhoven to supply 25,000 completed EF50 devices and 500,000 pre - formed EF50 bases that would jump start the bulk manufacture of EF50 valves in England and these were shipped on the 9th of May 1940 by road freight and thence a Zeeland Steamer Company ship.

After a harrowing journey in which the ship was attacked and damaged by Stuka dive bombers, the ship with it's precious cargo arrived safely in England, six days later - a few days after Dr Roberts' escape. With both man and materials safe, Mullard and the EF50 went on to play a pivotal part in the Allies' success, so much so, that the EF50 was crowned ' The Valve that Won the War!' but more on that particular story in a future blog entry!


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