5X4 5X4G CV1851 tube Marconi Italy pair tubes rectifier valve square twin getter

two tubes TUBE 5X4G MARCONI MADE IN ITALY 

TESTED TV7D/u = 60/60 & 60/58 (REFERENCE GOOD 40/40) 

double square GETTER UPPER 

LONG grey PLATE BLACK BASE

RARE TUBE POWER RECTIFIER 

tested strong & balanced systems 

5X4G = 5X4 = CV1851

Similar tubes other wirings:   5U4G

First Serie 26.May.1936 

Sub the model 5Z3  

Socket Octal (Int.Octal, IO) K8A, USA 

Filament Heater Vf 5 Volt / If 3 Ampere / Direct

box 161