Sylvania JHS-12AT7WA 12AT7 ECC81 Vacuum Tube Milspec NOS NIB For Your Univalve Twelveslseven

Sylvania JHS-12AT7WA 12AT7 ECC81 Vacuum Tube Milspec NOS NIB For Your Univalve TwelveslsevenThis new old stock, new in box, milspec Sylvania JHS 12AT7WA (12AT7 ECC81) dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. It measured 51 56 where minimum (65%) is 50 50 and 100% is 77 77. 12AT7s are notorious for their unmatched triodes and their deviation from nominal parameters. And though this tube tests two standard deviations from the mean, it is new old stock and is

They have 4-48 188-5 and 5-43 188-5 date/provenance codes

The face has quite a nice patina and the case has a wonderful

This matched pair of Sylvania black glass 6AQ5 output tubes was tested on our Paul Hart-calibrated TV7/U for shorts

55 and 59 where minimum (65%) is 40

wire or mica snubbers (for low microphonics) and excellent flashing

Tube Two has a narrow crack in its base which

new in box Zenith 17AY3 / 17AY3A / 17BS3 / 17BS3A tubes tested to spec on our Paul Hart-calibrated TV7/U

Transconductance measured 56/56 for Tube One and 58/58 for Tube Two where minimum (65%) is 25/25 and 100% is 38

new in box Sylvania 6C5GT tube tested to spec on our Paul Hart-calibrated TV7/U

60 and 60 where minimum (65%) is 40

(New 12AU7s typically test within one standard deviation of 2200 micromhos

Two have MISSING CENTERING PINS