Lansdale 12AU7 / ECC82 Vacuum Tube 17MM Black Plates Copper Support Rods Early Production 12DB5 Nonal T13 52 and 60 where minimum

52 and 60 where minimum (65%) is 36 and 100% is 55

This  pair of National Union black plate 45 output triode was tested on our Paul Hart-calibrated TV7/U for shorts

Transconductance measured 68/64 where minimum (65%) is 36/36

3 milliamps' plate current and measured 2060 micromhos

They measured 45

Lansdale 12AU7 / ECC82 Vacuum Tube 17MM Black Plates Copper Support Rods Early Production 12DB5 Nonal T13 52 and 60 where minimumThis Lansdale (Philco's in house tube manufacturing arm) 12AU7 ECC82 dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. It measured 70 64 where minimum (65%) is 56 56 and 100% is 86 86. It has shiny 17MM black plates; copper support rods; excellent flashing; a top slanted D getter and L1E date codes. This is an early production 12AU7 not a 12AU7A like most 12AU7s we see these