Matched Pair National Union NU Number Type 37 #37 Vacuum Tubes Valves Black Plate Shoulder ST Shape NOS-Testing 5551 These three Sylvania plate number

These three Sylvania plate number 78 tube were tested on our Paul Hart-calibrated TV7/U for shorts

nicely-matched pair of Ken-Rad 6SJ7s was tested on our Paul Hart-calibrated TV7 for shorts

Ken-Rad-MANUFACTURED 6K6 / 6K6G tube was tested on our Maxi Matcher II with 325 volts on the plates and a bias of -36 volts for shorts

but I have not been able to find a commercially-made amplifier for them and have had no time to build one

gray plates and excellent flashing

Matched Pair National Union NU Number Type 37 #37 Vacuum Tubes Valves Black Plate Shoulder ST Shape NOS-Testing 5551 These three Sylvania plate numberThis new old stock testing matched pair of National Union MANUFATURED Type 37 triodes was tested on our Paul Hart calibrated TV7 For shorts, gas and transconductance. There were no shorts or gas. They measured 36 and 37 (RCA LABELED, NU MANUFACTURED) where minimum (65%) is 23. They have black plates; dimpled sheet getters; old fashioned, coke bottle shape glass envelopes and terrific flashing. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT