(1) Tested GE 6KA8 Tube with Box Great Britain Date Code HI Triode Pentode

(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 Motorola 6BL8 Tube Date Code 7M-431 Made in Japan Triode Pentode Tube

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

(1) Tested Motorola 6DX8 Tube Date Code 7M-1584 Japan Triode Pentode Tube

(1) Tested Westinghouse 6JW8 Tube Date Code 81-09 Triode and Pentode Tube (b)

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