Matched Pair National Union NU 6V6 6V6GT Black Glass Vacuum Tubes NOS-Testing Rudy Rosa 1976 new in box RCA 12AV6

new in box RCA 12AV6 tubes tested to spec on our Paul Hart-calibrated TV7/U

Both have 939 date codes

They have NU 188-5 and 3-09 188-5 date/provenance codes

It measured 52/55 where minimum (65%) is 38 and 100% is 58

new in box Zenith 10EM7 tube tested to spec on our Paul Hart-calibrated TV7/U

Matched Pair National Union NU 6V6 6V6GT Black Glass Vacuum Tubes NOS-Testing Rudy Rosa 1976 new in box RCA 12AV6This new old stock testing matched pair of National Union 6V6GT blackout glass output tubes was tested on our Maxi Matcher 2 with 400 volts on the plates and a bias of 36 volts for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 2670 micromhos for Tube One and 2430 for Tube Two. Plate current measured 27. 8 and 27. 9 milliamps, respectively. (New US made 6V6s typically test with plate current from the mid teens