NOS Pair Raytheon 12AY7 Black Plate Vacuum Tubes | Square Getters | Matched Codes 1953 Production. Tested on an Amplitrex AT1000.
General Electric 12AY7 Tube “D” Getter B&K 707 GM & 606 Emissions TESTED
Tested @ 88/81 GM on B&K Mutual Conductance tester and @ 87/85 for emissions on B&K Dyna Jet 606. No logo but model of tube is visible. See photos.