(1) Tested GE 6GH8A Tube Date Code SA Halo Getter Triode Cutoff Pentode Tube

(1) Tested Lindal 6GH8A Tube with Box Japan Code 448 Triode Sharp Pentode (a)

(1) Tested RCA 6GH8A Tube with Box Date Code HE Triode Sharp Cutoff Pentode Tube

(1) Tested Lindal 6GH8A Tube with Original Box Triode Sharp Cutoff Pentode

(1) Tested Lindal 6GH8A Tube Japan Code 448 Triode Sharp Cutoff Pentode (b)

(1) Tested Strong Sylvania 6JC8 Tube Date Code NR JAG Triode Pentode Tube

(1) Tested Sylvania 5X8 Tube with Box Date Code df JAS Triode Pentode Tube

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