Matched Pair General Electric GE 6K6 6K6GT Vacuum Tubes Black Glass NOS-Testing CAL 403 new in box RCA 6GK5

new in box RCA 6GK5 tubes tested to spec on our Paul Hart-calibrated TV7/U

I have played it in my Schiit Vali 2 headphone amp and it sounds great

This new old stock-testing National Union globe / balloon-style bottle number 36 tube tested 42 on our Paul Hart-calibrated TV7/U where minimum (65%) is 26 and 100% is 40

They have DC and BD date codes

The spine is in fine shape with no loose pages and the dust jacket is without nicks or tears

Matched Pair General Electric GE 6K6 6K6GT Vacuum Tubes Black Glass NOS-Testing CAL 403 new in box RCA 6GK5This matched pair of GE MANUFACTURED 6K6 6K6GT tubes was tested on our Maxi Matcher 2 with 325 volts on the plates and a bias of 36 volts for shorts, gas, plate current and transconductance. There were no shorts or gas. Tube One measured 1940 micromhos, 29. 3 milliamps' plate current. Tube Two measured 1880 31. 8. New nominal is within one standard deviation of 1900. These tubes have copper support rods; rectangular mica spacers; black and silver