Description
Tube Type / Number: 12SN7GT
Actual Brand*: Martron
Printed Brand: Martron
Quantity of Tubes: Single
Plate Construction: Flat Gray Ribbed
Getter Construction: Side Fat D
Country of Manufacture: USA
Visible Date Codes: 56-17
Lettering Condition: 90 Percent
Year Made:
Mica Spacers: 2
Smoked Glass? No
Engraved Base? No
Boxes Included? 1 Box - Not Original
Notes: Short Base, Copper Grids
Gm Test Results: 90/60
Minimum Good Value: 50/50
NOS Test Value: 82/82
Life Calculation: 110/73% (where 65% = fail)
Tests as NOS?: No
True NOS?*: No
** Please note, many tubes will test NOS but will actually have a few hours of use on them. A truly NOS tube will have excellent getter flashing condition, no dirt/grime, usually in the original box, and no filament deposits. If a tube is listed as "tests NOS" but is listed as "not True NOS" please expect the tube to have a small amount of use *
All tubes have been tested using only the best tube testers. We have a large fleet of tube testers, and every single one of them has been calibrated within the last year by industry experts. We mainly use the Hickok TV-7D/U, but occasionally we may use a Hickok 539, 533A, or 600A.