Matched Pair Sylvania 6C4 Vacuum Tubes Black Plates Copper Support Rods Ken-Rad NOS-Testing with a very low noise

with a very low noise floor and excellent soundstaging

This is a testament to their high emissions

This new old stock-testing Sylvania 6L6GC was tested on our Maxi Matcher 2 for shorts

new in box RCA 14Q7 tubes tested to spec in our Jackson 648 Mutual Conductance tester

new in box US-made 6AS8 tubes tested to spec on our Paul Hart-calibrated TV7/U

Matched Pair Sylvania 6C4 Vacuum Tubes Black Plates Copper Support Rods Ken-Rad NOS-Testing with a very low noiseThis 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