NOS Matched Pair Ruby China KT66-STR Gray Plate OO Get Brown Base Vacuum Tubes

Tube Type / Number: KT66-STR
Actual Brand*: Ruby
Printed Brand: Ruby
Quantity of Tubes: Matched Pair
Plate Construction: Gray
Getter Construction: Bottom OO
Country of Manufacture: China
Visible Date Codes:
Lettering Condition: 100 Percent
Year Made:
Number of Mica Spacers: 2
Mica Shape: Razor Diamond
Smoked Glass? Clear
Engraved Base? No
Boxes Included? Multiple Boxes - NONE Original
Notes: Brown Base [2]

Gm Test Results: 5200 & 5300
Minimum Good Value: 3880
NOS Test Value: 5200
Life Calculation: 100+% (where 65% = fail)

Tests as NOS?: Yes
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.