Matched Pair RCA Black Plate 6AU7 Vacuum Tubes NOS-Testing Музыка Барокко Transconductance measured 59 for both

Transconductance measured 59 for both tubes where minimum (65%) is 40

new in box CBS-Hytron 8CS7 tested to spec on our Paul Hart-calibrated TV7/U

These milspec Ken-Rad JAN-CKR-6L7 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

This new old stock-testing RCA clear top 6CG7 / 6FQ7 dual triode was tested on our Paul Hart-calibrated TV7/U for shorts

Matched Pair RCA Black Plate 6AU7 Vacuum Tubes NOS-Testing Музыка Барокко Transconductance measured 59 for bothThis 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