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

(1) Tested Philco 6AT6 Tube Date Code 50-13 Dual Diode High Mu Triode Tube

(1) Tested Silvertone 18FY6 Tube Twin Diode High Mu Triode Tube

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

(1) Tested Amperex EBC90/6AT6 Tube Code Y23◢9L EBC90 6AT6 Twin Diode Triode Tube

(1) Tested RCA 6BF6 Tube Date Code KG Twin Diode Medium Mu Triode Tube

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

RCA 7F7 High MU Twin Triode Tube