(1) Tested RCA 6SN7GT Tube.
Date Code 509.
Black offset plates with copper grid posts and a bottom square D getter.
The tube number is worn off of the glass.
The wording on the base is faded but still recognizable as being RCA branded.
This tube tests as NOS.
Tested on a calibrated Hickok TV-10 military tube tester and exhibiting no shorts or leaks with the following results:
Test Result = 2500-2625 micromhos
Minimum pass/good = 1650-1650
NOS Target Value = 2475-2475
Also performance tested in-circuit through a Class A amplifier with no microphonics detected.
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