Matched Pair Sylvania 6AU6 Vacuum Tubes Valves NOS-Testing RCA Black Plate They have 0-09 188-5 and

They have 0-09 188-5 and 9-04 188-5 date / provenance codes

Transconductance readings are indicated on the tops of the tubes

black plate 12AT7WA / ECC81 dual triode was tested on my Hickok 600A for shorts

58 and 67 where minimum (65%) is 48

Date Codes: none

Matched Pair Sylvania 6AU6 Vacuum Tubes Valves NOS-Testing RCA Black Plate They have 0-09 188-5 andThis new old stock testing matched pair of Sylvania 6AU6 tubes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 82 for Tube One and 84 for Tube Two where minimum (65%) is 58. These tubes have top, U getters; gray plates and excellent flashing. I am playing them in my Musical Paradise MC 3 single ended integrated amplifier (with adapters, not included) with Aimee