Matched Pair RCA Black Plate 6AU7 Vacuum Tubes NOS-Testing 1N6 NOS NIB Tube One measured 61/60 while

Tube One measured 61/60 while Tube Two measured 63/65 where minimum (65%) is 50/50 and 100% is 77/77

(New US-made 6L6GCs typically test with plate current from the low 20s to mid 30s with transconductance from 2200 micromhos or so

1 milliamps with a transconductance of 2640 micromhos while Tube Two measured 30

Transconductance measured 1800 and 2100 micromhos

Matched Pair RCA Black Plate 6AU7 Vacuum Tubes NOS-Testing 1N6 NOS NIB Tube One measured 61/60 whileThis new old stock testing, perfectly matched pair of RCA black plate 6AU7 dual triodes was tested on our Hickok 800 for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 2600 2600 micromhos for both tubes. (New 6AU7s typically test within a standard deviation of 2400 micromhos). I am playing them in my Alan Eaton single ended triode amplifier (with adapters, not included) as I write and they sound great. These