Matched Pair Sylvania 6C4 Vacuum Tubes Black Plates Copper Support Rods Ken-Rad NOS-Testing This is a testament to

This is a testament to their high emissions

I can't tell you how they sound as we don't have any equipment that runs them

new in box Sylvania 12AV7 dual triode was tested on our Paul Hart-calibrated TV7/U for shorts

with a very low noise floor and excellent soundstaging

Delco-BRANDED 6SK7 tested as good on our Paul Hart-calibrated TV7/U

Matched Pair Sylvania 6C4 Vacuum Tubes Black Plates Copper Support Rods Ken-Rad NOS-Testing This is a testament toThis almost perfectly matched pair of Sylvania black plate 6C4 triodes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Tube One measured 60 while Tube Two measured 62 where minimum (65%) is 55 and 100% 85. They have top D getters; copper support rods and nice flashing. They sound great in my Alan Eaton single ended 45 amplifier (with an adapter, not included). WE HAVE SCORES OF THOUSANDS