Matched Pair Tung-Sol 6K6 6K6GT Black Bottles Vacuum Tubes NOS-Testing CBS NOS NIB They have 4-39 188-5 and

They have 4-39 188-5 and 3-43 188-5 date codes/EIA code

Transconductance measured 57 for Tube One and 65 for Tube Two where minimum (65%) is 36 and 100% is 55

This matched pair of milspec/industrial GE 5814A / 12AU7 / ECC82 dual triodes was tested on our Hickok 800 for shorts

54/54 and 54/54 where minimum (65%) is 40/40 and 100% is 62/62

things have obviously improved

Matched Pair Tung-Sol 6K6 6K6GT Black Bottles Vacuum Tubes NOS-Testing CBS NOS NIB They have 4-39 188-5 andThis new old stock TESTING matched pair of Tung Sol 6K6GT tubes was tested on our Maxi Matcher 400 volts on the plates and a bias of 36 volts for shorts, gas and transconductance. There were no shorts or gas. Tube One drew 25. 6 milliamps' plate current and measured 2000 micromhos. Tube Two measured 25. 8 2040. New nominal is within one standard deviation of 1900. These tubes have pretty black bottles that entirely cover the top half of the tubes;