(1) Tested Dumont 6S4A Tube Date Code 61-26 Medium Mu Triode Tube

(1) Tested GE 6JC8 Tube with Box Date Code SC General Electric Triode Pentode

(1) Tested Raytheon 6S4A Tube with Box Japan Code M14 Medium Mu Triode Tube

(1) Tested GE 6DN6 Tube Date Code MU General Electric 6DN6 Beam Power Tube (a)

(1) Tested GE 6J6A Tube Code CW General Electric 6J6 A Medium Mu Twin Triode

(1) Tested GE 6AX4GTB Tube Date Code MU General Electric 6AX4 GTB Rectifier

(1) Tested GE 6J6A Tube Date Code SU GE 6J6 A Tube Medium Mu Twin Triode

(1) Tested GE 6J6A Tube Code SW General Electric 6J6 A Medium Mu Twin Triode