Catalogue
530 of 655 records previous / next
Marconi-Osram Radio Valve Type MPT4, by Marconi Company, London, Late 1920s
Inventory Number: 84752
Number of documents: 3
Document Type: Miscellaneous Note
Document Heading: Historical Background - British Radio Valve Manufacturers' Association (BVA)
Text:
The British Radio Valve Manufacturers' Association (BVA) was established in July 1926 and was a registered trade union. It had been preceded by the Valve Manufacturers' Association, which had established a 'Memorandum of Sales Plan'. This agreement, which was signed by the seven major British valve manufacturers, secured a uniform practice in the sale of radio valves for broadcasting purposes in the UK. Practical examples included similar discounts and sales conditions, and were considered a form of restrictive practice. This association continued into the 1950s.
Document Type: Miscellaneous Note
Document Heading: Technical Details
Text:
MOV had trouble designing the MPT4. Not only did it take them a clear two years to produce technically successful copies of Mazda's landmark AC/Pen but thereafter they had to redesign it several times (including the beam tetrode version MKT4) over the next 5 or 6 years. In the end they solved the problem by buying equivalents from other manufacturers and relabelling them. Part of the problem was that MOV had invested heavily in the azide process during the late 1920s and were either unable or unwilling to switch overnight to manufacturing oxide-coated cathodes of the rating and quality demanded by powerful, for that time, audio output valves. Another factor was that MOV were strongly anti-pentode at that time and may have been unwilling to invest in proper, full-scale development in what was, for them, a new and uncharted field. Instead they put their money into circumventing the pentode - by inventing the beam tetrode, with some help from RCA in America.
Document Type: Miscellaneous Note
Document Heading: Manufacturer Details
Text:
Marconi-Osram Valve Co. Ltd. was founded in 1919, and took over the manufacture of Marconi valves from Ediswan, the trade name of the Edison and Swan United Electric Light Company Limited. The M-OV, as it was later known, was a joint Marconi-GEC valve-manufacturing company. It produced all of its valves at the Osram Lamp Works at Hammersmith, London.
530 of 655 records previous / next
Record mode: Basic | Medium Images | Large Images | Documents (3)