Matched Pair Sylvania 6BL7 6BL7GT Vacuum Tubes Black Plate Triple 3 Mica NOS NIB Matched Pair 6AU6 new in box US-made 6X8

new in box US-made 6X8 tubes tested to spec on our Paul Hart-calibrated TV7/U

What makes this funny is that a major US defense contractor likely committed a number of felonies by smuggling communist Soviet tubes into the US at the height of the Cold War

Transconductance measured 49/56

pops and ticks

new in box National Union 14J7 tube tested to spec on our Paul Hart-calibrated TV7/U

Matched Pair Sylvania 6BL7 6BL7GT Vacuum Tubes Black Plate Triple 3 Mica NOS NIB Matched Pair 6AU6 new in box US-made 6X8This new old stock, new in box (for Tube One (centering pin missing)) matched pair of Sylvania 6BL7GT dual triodes was tested on our TV7 U for shorts, gas and transconductance. There were no shorts or gas. Tube One (centering pin missing) measured 46 46 while Tube Two measured 50 46 where minimum (65%) is 25 25 and 100% is 39 39. These tubes have copper support rods; beefy black ladder plates; three (rather than two) mica spacers for improved