Matched Pair Sylvania 6F6 6F6GT Vacuum Tubes Clear Bottles NOS-Testing

Matched Pair Sylvania 6F6 6F6GT Vacuum Tubes Clear Bottles NOS-TestingThis 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;

2 milliamps and transconductance was 2460 micromhos for Tube One (Raytheon-BRANDED)

an silkscreened base

34 and 35 where minimum (65%) is 25

RF shielding

It sounded great in my Bottlehead

new in box Cetron JAN-6278 tube is hermetically sealed in foil packaging

but with some wear

Kreisler and Bach played masterfully by Abramas Sipolniek on Organ

new in box GE 6AG5 tubes tested to spec on our Paul Hart-calibrated TV7/U

Transconductance measured 18 for Tube One and 22 for Tube Two where minimum (65%) is 16 and 100% is 25

These four RCA-Radiotron type / number 41 tubes tested as follows on our Paul Hart-calibrated TV7/U:

7 and 38 milliamps