(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 Sylvania 6GH8A Tube with Box Date Code ae Triode Sharp Cutoff Pentode

(1) Tested GE 6AF11 Tube Compactron Dual Triode Sharp Cutoff Pentode Tube (a)

(1) Tested Zenith 6GH8A Tube Date Code 18-09 Halo Getter Triode Cutoff Pentode

(1) Tested Sylvania 10GN8 Tube Date Code 1F High Mu Triode Sharp Cutoff Pentode

(1) Tested RCA 6AU8 Tube Medium Mu Triode Sharp Cut Off Pentode Tube