(1) Tested Coronado Type 27 Tube with Engraved Base Date Code Y 27 Tube Triode

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

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

(1) Tested National Union Type 35 Tube Engraved Base Date Code J Tetrode Tube

(1) Tested National Union 2C26 Tube Date Code HU Top Caps Brown Base Triode Tube

(1) Tested National Union 12BF6 Tube with Box Date Code 5326 Double Diode Triode

(1) Tested National Union 6N7 Tube Date Code NN Twin Power Triode Tube

(1) Tested RCA Cunningham Type 41 Tube Engraved Base Date Code J12 Power Pentode