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ID = 28718
Great Britain (UK)
Tube type:  Triode, vacuum   Universal 
Identical to R_Marconi = TM
Similar Tubes
Other shape (e.g. bulb type):
Normally replaceable-slightly different:
  ES4 ; RA_Mullard
Other class quality (otherwise equal):
First year 1922 Saga of the Vacuum Tube, Tyne page 380
Predecessor Tubes TM  
Successor Tubes 1925   R5V  

Base Europe 4-Pin B4 (Eu A, E, 4A) 1914
Was used by Radio/TV-reception etc.
Filament Vf 4 Volts / If 0.7 Ampere / Direct / Battery =

British version of the French TM of 1916. Tubes originally branded
Marconi's Wireless Telegraph Co. From the formation of the M O V co Ltd in 1919, the brand was changed to Marconi Osram. Tipless bakelite base versions of the tube were made from late 1925

Dimensions (WHD)
incl. pins / tip
x 118 x 55 mm / x 4.65 x 2.17 inch
Weight 52 g / 1.83 oz
Tube prices 8 Tube prices (visible for members only)
Information source Saga of the Vacuum Tube, Tyne   1925 Brown Brothers Catalog 217
The Saga of Marconi Osram Valve   20 page references

r_marconi_so.png R_Marconi: rtt
Anonymous 10 Collector

Just Qvigstad
Usage in Models 2= 1922? ; 7= 1922 ; 3= 1923

Quantity of Models at with this tube (valve, valves, valvola, valvole, válvula, lampe):12

Collection of




Gleicher Sockel, gleiche Daten, andere äussere Form. In 'The Saga of Marconi Osram Valve‘ von Vyse & Jessop wird sie auf Seite 55 als ‚pear-shaped‘ R-type beschrieben.

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