NOS Sleeve (5)Amperex ECC83 / 12AX7A W. Germany Siemens(?) Audio Amplifier Tubes
Here's a NOS sleeve of Amperex W. Germany 12AX7A/ECC83 tubes. Made in 1982. On my B&K 747 Gm tester where results are read in percent of new Gm value 0-120%, they test as follows: 110-110, 108-108, 102-120, 118-117, 100-100.