Tested Balanced Matched Pair of GE 6SN7GTA Tubes.
Date Codes 4-09 and 2-52.
The wording on one base is faded but still legible.
Tubes are balanced and matched for mutual conductance (Gm) and internal structure - they are identical.
Gray plates with copper grid posts, side horseshoe getters and top sawtooth mica spacers.
Tested on a calibrated Hickok TV-10 military tube tester with no shorts and no leaks with the following results:
Gm Test = 2750-2750 and 2750-2750 micromhos
Minimum pass/good = 1650-1650
Also performance tested in-circuit through a Class A amplifier with no microphonics detected.
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