Birk-Morton Vacuum Products Co.
Birk-Morton Vacuum Products Company, Owensboro, KY, USA
Last seen: 13-Mar-1925
Advertised for just a few months, the BM-201A was a brass based tipless tube. (it's a stock engraving in the radio news ad)
Given the references to Birk Morton's proximity to the Ken-Rad tube plant in Owensboro, B-M tubes were likely made by Ken-Rad, and was perhaps their short lived brand.
- Owensboro Messenger (Owensboro,KY), 23-Sep-1924, pg. 9. From Newspapers.com. Retrieved 24-Nov-2018. *
- Radio News, Sep-1924, pg. 339. From AmericanRadioHistory.com. Retrieved 19-Oct-2018. *
- Radio News, Feb-1925, pg. 1484. From AmericanRadioHistory.com. Retrieved 19-Oct-2018. *