EL503 TUBE PHILIPS POWER TUBES MATCHED QUAD VALVE TRIPLE OOO GETTER NEAR NOS

4X TUBES EL503 PHILIPS MATCHED QUAD SELECTED FOR AMPLIFIER 

TESTING CONDITIONS ON FUNKE W19S VA= 200V ; VG2=60V ; VG1=0V VF=6,3V

TESTED STRONG ALL 88mA (REFERENCE GOOS AT 48mA) SAME EMISSION FOR EACH TUBE 

3X CODE U33 +- 7L2 

1X CODE U33 +- 7L3 

TESTED ALSO ON TV7 TUBE TESTER WITH 6L6 SETTINGS AND ADAPTER 

TEST RESULTS = 100 ; 100; 98 ; 96 (REFERENCE GOOD AT 25) 

ORIGINAL VINTAGE POWER TUBES FULL LIFE DOUBLE TESTED 

RARE TUBES MATCHED QUAD

EL503 = 8278

Power TUBE Output 

Similar tube other base:  EL520

Multiple differences or of other kind:   8417

first serie 1965 

Sub the model EL34  

Socket Magnoval (9-Pins), B9D

Filamento Heater Vf 6.3 Volt / If 1.05 Ampere / Indirect  

BOX 136