(1) Tested Philco 6AT6 Tube Date Code 50-26 Twin Diode High Mu Triode Tube

(1) Tested RCA 6AT6 Tube Date Code LQ Twin Diode High Mu Triode Tube

(1) Tested RCA 6AT6 Tube with Box Date Code BF Twin Diode High Mu Triode Tube

(1) Tested Strong Ken-Rad 12AT6 Tube Date Code 6-30 Twin Diode High Mu Triode

(1) Tested Sylvania 6T8A Tube Date Code ab ESO Triple Diode High Mu Triode Tube

(1) Tested Philco 6J6 Tube Date Code 50-16 Medium Mu Twin Triode 6J6 S Tube

(1) Tested Philco 6ES5 Tube Date Code BBC High Mu Triode Tube

Philco 7C6 Dual Diode / Triode Vacuum Tube