Matched Pair RCA 6GU7 Vacuum Tubes NOS NIB RCA OSC They have DC and BD

They have DC and BD date codes

This General Electric 22JF6 tube tested 75 on our Paul Hart-calibrated TV7/U where minimum is 54 and new is 100

100% is 56/56

This lot of three US-made type 42 tubes was tested our Paul Hart-calibrated TV7/U for shorts

Here's a new old box

Matched Pair RCA 6GU7 Vacuum Tubes NOS NIB RCA OSC They have DC and BDThis new old stock, new in box matched pair of RCA 6GU7 dual triodes was tested on our Jackson 648 Mutual Conductance tester for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 95% 100% for Tube One and 95% 105% for Tube Two. (New 6GU7s typically test from within a half standard deviation of 2000 micromhos and the Jackson expresses this in terms of a percentage.) I have played it in my Alan Eaton single ended