For sale is a 12AX7 Amperex tube with date code mC1 D6K that tests to spec and was tested on my calibrated TV-7 A/U tester.
Tester minimum value: 32/32
Tube tests: 53/53
Also, due to a recent scammer: I must sell all my vintage units and items as is, with no guarantees and or returns for parts or repair!