Matched Pair Sylvania 6F6 6F6GT Vacuum Tubes Clear Bottles NOS-Testing 3A3 Plate Cap These six US-made 6S4A tubes

These six US-made 6S4A tubes were tested on our Paul Hart-calibrated TV7/U for shorts

new in box Ken-Rad 6R7 tube tested to spec on our Paul Hart-calibrated TV7/U

I am playing it in my Musical Paradise MP-301 with another

5-35 188-20 date/provenance codes and nice flashing

It measured 76 where minimum (65%) is 50 and 100% is 77

Matched Pair Sylvania 6F6 6F6GT Vacuum Tubes Clear Bottles NOS-Testing 3A3 Plate Cap These six US-made 6S4A tubesThis new old stock TESTING matched pair of Sylvania 6F6GT tubes was tested on our Maxi Matcher 325 volts on the plates and a bias of 36 volts for shorts, gas and transconductance. There were no shorts or gas. Tube One drew 30 milliamps' plate current and measured 2000 micromhos while Tube Two measured 30. 5 2110 where new 6F6s measure from approximately 2000 micromhos or so with plate current draw in the 20s. These tubes have gray, three hole plates;