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ID = 33214
Great Britain (UK)
Brand: Marconi-Osram - (Valves/Tubes); GB
Developer: Marconi-Osram - (Valves/Tubes); GB 
Tube type:  Triode, vacuum   Power/Output 
  Ca. 1925 up to 1945 very rare. ***
Identical to G445B = VT68_GPO = CV1651

Base Europe 4-Pin B4 (Eu A, E, 4A) 1914
Was used by Telephony
Filament Vf 4 Volts / If 0.45 Ampere / Direct / Specified voltage AC/DC

The G445B (VT68 is the G.P.O. reference number) was developed for the U.K.'s Post Office by Marconi-Osram as a replacement for the LS series used in telephony. It was a long life tube with a more robust and lower power filament than the LS(5B). The nickel ribbon filament operated at 1.8W compared with 4.2W for the LS type used in the line amplifiers.
The tube was subsequently incorporated in the CV1651 specification which was manufactured until about 1945 by other companies as the tubes were still required for telephony amplifiers.
The shape of the later tubes differs from the initial balloon shape of the early tubes.

Dimensions (WHD)
incl. pins / tip
52 x 128 x mm / 2.05 x 5.04 x inch
Weight 60 g / 2.12 oz
Information source - - Manufacturers Literature   
The Saga of Marconi Osram Valve   Pages 136 & 137
Babani, International Radio Tube Encyclopaedia

b4_1~~29.png G445B: Fin Stewart
Fin Stewart

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