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ID = 44759
Great Britain (UK)
Brand: Marconi's Wireless Telegraph Co. Ltd.
Tube type:  Beam Power Tube   Power/Output 
Identical to TT21 = 7623
Similar Tubes
Heater different:

Base Octal (Int.Octal, IO) K8A, USA 1935 Top contact with a cap.
Filament Vf 6.3 Volts / If 1.6 Ampere / Indirect / Specified voltage AC/DC
Description Designed for use as RF amplifiers with full power rating up to 30MHz. Also useful as audio amplifiers and pulse modulators.

Pa <37.5W for commercial service or <45W for intermittent or amateur service.

Va<1250, Ik<230mA.
Typical Output Powers:
RF: 80W SSB class AB1;
for Audio in push-pull: 100 W (Push-Pull 43% tap,Ultra-Linear Connected). 

Dimensions (WHD)
incl. pins / tip
52 x 131 x 52 mm / 2.05 x 5.16 x 2.05 inch

TT21: Radio Communication Handbook
Antonio Rabitti

tt21pins.png TT21: GEC data sheet
Bruce Taylor

Just Qvigstad
Usage in Models 1= 1956 ; 1= 1958? ; 1= 1970?

Quantity of Models at with this tube (valve, valves, valvola, valvole, válvula, lampe):3

Collection of



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