(1) Tested Sylvania 2AF4B Tube Date Code XY Medium Mu Triode Tube

(1) Tested Delco Type 27 Tube Date Code A8 Medium Mu Triode 27 Tube

(1) Tested Sylvania Type 27 Tube Date Code A5R Engraved Base 27 Tube Triode

(1) Tested Sylvania Type 27 Tube with Engraved Base Date Code E6R 27 Tube Triode

(1) Tested Sylvania 6BN4A Tube Date Code cj ABU Medium Mu Triode 6BN4 A Tube

(1) Tested Westinghouse 2AF4A Tube Date Code 61-13 Medium Mu Triode Tube (a)

(1) Tested RCA 6BF6 Tube Date Code KG Twin Diode Medium Mu Triode Tube

(1) Tested RCA Radiotron Type 27 Tube Date Code T6 Medium Mu Triode Tube