Matched Trio Sylvania 12B4 12B4A Vacuum Tubes NOS NIB 6GV5 NOS NIB This new old stock-TESTING matched

This new old stock-TESTING matched pair of Sylvania 6F6GT tubes was tested on our Maxi-Matcher -- with 325 volts on the plates and a bias of -36 volts -- for shorts

Transconductance was 1890 for Tube One and 2000 for Tube Two where new/nominal is within one standard deviation of 1900

These six Cunningham C-324 globe

where minimum (65%) is 25/25 and 100% is 38

67 and 71 where minimum (65%) is 46

Matched Trio Sylvania 12B4 12B4A Vacuum Tubes NOS NIB 6GV5 NOS NIB This new old stock-TESTING matchedThis new old stock, new in box matched trio of Sylvania MANUFACTURED, Emerson BRANDED 12B4A tubes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. They measured 44, 44 and 48 where minimum (65%) is 32 and 100% is 49. Wish I could tell you how they sound, but I don't have any equipment that uses these. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE MAY HAVE IT. PLEASE