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ID = 50575
Great Britain (UK)
Brand: Ediswan, Siemens Edison Swan Electric Co.; London
Developer: Ediswan, Siemens Edison Swan Electric Co.; London 
Tube type:  Triode, vacuum   Universal 
  <1925 rare.
Identical to AR
Similar Tubes
Other base:
First Source (s)
1922 : - - Manufacturers Literature
1922 : History of the British Radio Valve to 1940 p. 155

Base Europe 4-Pin B4 (Eu A, E, 4A) 1914
Was used by Radio/TV-reception etc.
Filament Vf 4 Volts / If 0.75 Ampere / Direct / Battery =

Ra = 36.0 kOhm, slope = 0.17 mA/V, amplification factor = 6.0
. First made in 1922. For several months in 1923 the tube was available with the "Ediswan Safety Cap". The purpose of this base was to stop accidental connection of the filament pins to that of the plate or anode hole in the tube socket. The bases were only the British B4 designation and had three pin lengths. plate/anode and grid pins 18 mm, one filament pin 14.5 mm and the other 12 mm. No other tube manufacturer used these bases and it was not long before they were discontinued by the company. These bases were only used on receiving tubes.

From 1913, the Ediswan company was permitted to use the word "Royal" on lamps (light bulbs) and the this was by Decree from the British Royal Family.The word also appeared on at least four other Ediswan tubes made between 1918 and 1922. (exact dates not known). According to John Stokes, in his book "70 years of radio tubes and valves", page 190, the word was discontinued during 1922.It is assumed that the word "Royal" on radio tubes was not authorised in the first place. Tubes known to have used the word are AR, C, ES4 (2) and R

Dimensions (WHD)
incl. pins / tip
35 x 110 x mm / 1.38 x 4.33 x inch
Weight 47 g / 1.66 oz
Tube prices 3 Tube prices (visible for members only)
Information source - - Manufacturers Literature   1924
British Radio Valves - The Vintage Years: 1904-1925   Pages 30, 87 @ 115
70 Years of Radiotubes and V.
Saga of the Vacuum Tube, Tyne

b4_base_pins~~30.png AR: Fin Stewart
Fin Stewart

Just Qvigstad
AR: own collection
Peter den Boer

Usage in Models 1= 1923

Quantity of Models at with this tube (valve, valves, valvola, valvole, válvula, lampe):1

Collection of



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