(1) Tested Zytron 5U8 Tube Date Code 709 Triode Pentode Tube

(1) Tested Tung Sol 5U8 Tube with Box Date Code NC1 Triode Pentode Tube

(1) Tested Rad-Tel 6X8 Tube Date Code 5-66 6X8 Triode Pentode Converter Tube

(1) Tested Tung-Sol 6AW8A Tube Date Code PRI 6AW8 A High Mu Triode Pentode

(1) Tested Sylvania 5X8 Tube Date Code GL ELM Triode Pentode Converter Tube

(1) Tested GE 5AN8 Tube with Box Date Code 59-04 General Electric Triode Pentode

(1) Tested Tung-Sol 6J5 Tube Date Code 518-3 Tung Sol 6J5 Medium Mu Triode Tube

(1) Tested Tung-Sol 12SG7 Tube Date Code MR3 Tung Sol Remote Cutoff Pentode Tube