Matched Pair National Union NU Number Type 37 #37 Vacuum Tubes Valves Black Plate Shoulder ST Shape NOS-Testing 5551 gray plates and excellent flashing

gray plates and excellent flashing

These five GE 1A7GT tubes tested to spec on our Paul Hart-calibrated TV-7/U

new in box (For Tube One) GE 6SL7GT dual triodes was tested on our Paul Hart-calibrated TV7/U for shorts

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

Unfortunately it is MISSING ITS CENTERING PIN (please see Picture Four for a close-up) and has been marked for safe-and-easy insertion

Matched Pair National Union NU Number Type 37 #37 Vacuum Tubes Valves Black Plate Shoulder ST Shape NOS-Testing 5551 gray plates and excellent flashingThis 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