(1) Tested Sylvania 6KA8 Tube with Box Date Code RAA Triode Pentode Tube

(1) Tested RCA 6KA8 Tube with Box Date Code GJ Triode Pentode Tube

(1) Tested Zenith 6KA8 Tube Date Code 72-17 Great Britain Triode Pentode Tube

(1) Tested Ford Philco 6KA8 Tube with Box Japan Date Code 2L Triode Pentode (a)

(1) Tested Sylvania 6JV8 Tube with Box Date Code NR AAA Triode Pentode Tube

(1) Tested Westinghouse 6KA8 Tube with Box Date Code 67-43 Triode Pentode Tube

(1) Tested RCA 6CX8 Tube with Box Date Code CR Medium Mu Triode Pentode Tube

(1) Tested GE 6JV8 Tube and Box Date Code NJ General Electric Triode Pentode (a)