Sylvania 5U4 5U4GB Vacuum Tube Rectifier Black Plate Nine Eleven Transconductance measured 72 for Tube

Transconductance measured 72 for Tube One and 76 for Tube Two where minimum (65%) is 58

but I glued it anyway

58 and 71 where minimum (65%) is 50

new in box GE 22JR6 tubes tested to spec on our on our Jackson 648

Sylvania 5U4 5U4GB Vacuum Tube Rectifier Black Plate Nine Eleven Transconductance measured 72 for TubeThis black plate Sylvania 5U4GB rectifier tube tested 52 48 in Sections One and Two, respectively, on our Paul Hart calibrated TV7 U where minimum (65%) is 40 40 and 100% is 62 62. It has a top O getter; a crenelated top mica spacer; black plates and jd AED date codes. THIS TUBE'S CENTERING PIN IS MISSING AND IT HAS BEEN MARKED FOR SAFE AND EASY INSERTION. THERE IS A CLOSE UP PHOTO OF THE BASE TO SERVE AS A REMINDER. WE HAVE SCORES OF THOUSANDS OF