Radio Valve Company Ltd.
189 Dufferin St, Toronto

Radio tube manufacturer for three major Canadian companies: CGE, Marconi and Westinghouse

In November 1926 a decision was made by Canadian General Electric (Canada)(C.G.E. or CGE) Toronto, ON; Canadian Marconi Co. Ltd. (CMC, Esterline) and Canadian Westinghuse Co, to form a "patent pool" to exchange patents etc. (other companies were signatories). The new concern was to be known as Canadian Radio Patents Ltd. To consolidate tube manufacture, a further company was created for manufacture of tubes for the above named concerns. 

This company was the Radio Valve Company of Canada Ltd. and production started early in 1927. Little has been located so far about the initial years but receiving and transmiting tubes were made. A time frame has not been located but for many years but brand names (CGE, Marconi or Westinghouse) was printed on the tube base in red ink. This branding often included "Made in Canada for (the relevent company)". There may have been a quota for each company. 

A list of CMC tubes from 1939 has details of over 160 receiving tubes.