Sylvania 12AV7 Vacuum Tube Black Plate NOS-Testing Sylvania NOS-Testing These seven US-made 5V6GT tubes

These seven US-made 5V6GT tubes tested as follows on our TV7/U: 40

Tube One measured 1940 micromhos

steel plates and steel suppost rods

This lot of six Sylvania number / type 58 stamped- / engraved-base tubes was tested on our Paul Hart-calibrated TV7/U for shorts

new in box RCA RCA 3AT2 / 3AT2B / 3AW2 tubes tested to spec on our Paul Hart-calibrated TV7/U

Sylvania 12AV7 Vacuum Tube Black Plate NOS-Testing Sylvania NOS-Testing These seven US-made 5V6GT tubesThis new old stock testing Sylvania 12AV7 dual triode was tested on our Jackson for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 116% 104% where minimum (65%) is 70% 70%. This tube has black plates; a horseshoe getter and terrific flashing. I am playing it in Bottlehead Crack headphone amplifier as a 12AU7 substitute and it sounds excellent. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE