This is a vintage RCA 12AU7 ECC82 tube with a black long plates and D getter, likely manufactured in the 1950s in the United States.

Got this from electronics/TV store closing auction of inventory parts. Box shows signs of wear from storage and is missing top flaps. Tube has some smeared printing.

Tested per user manual procedures on recently calibrated Hickok 6000A.

Passed all tests:

Filament Continuity Test: Passed

Shorts Test: Passed

Quality Test: Passed

Mutual Conductance Test: 2200 & 2200/2200 (2200= NOS MINIMUM)

Gas (Grid Current) Test: Passed

Life Test: Passed

Matched TRIODES

Also Tested on THD BI VALVE Amp. Works and sounds great. Very low noise and musical tube.