Sylvania JHS-12AT7WA 12AT7 ECC81 Vacuum Tube Milspec NOS NIB For Your Univalve Twelveslseven new in box Zenith 17AY3

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

new in box Sylvania 6C5GT tube 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 12AU7s typically test within one standard deviation of 2200 micromhos

Sylvania JHS-12AT7WA 12AT7 ECC81 Vacuum Tube Milspec NOS NIB For Your Univalve Twelveslseven new in box Zenith 17AY3This 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