Matched Pair Raytheon 6SD7 6SD7GT JANCRP6SD7GT Vacuum Tubes Milspec NOS NIB Korean War-Vintage M Garfield Cook new in box Siemens EBF89

new in box Siemens EBF89 / 6DC8 tube tested to spec on our Paul Hart-calibrated TV7/U

58 and 60 where minimum (65%) is 42

though this headphone amp is not optimized for this tube type

This Sylvania 6BS8 tube tested to spec on our Paul Hart-calibrated TV7/U

Matched Pair Raytheon 6SD7 6SD7GT JANCRP6SD7GT Vacuum Tubes Milspec NOS NIB Korean War-Vintage M Garfield Cook new in box Siemens EBF89This new old stock, new in box matched pair of Raytheon 6SD7GT JAN CRP 6SD7GT pentodes was tested on our Paul Hart calibrated TV7 for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 22 where minimum (65%) is 15. This Korean War vintage tube has US Army Signal Corps SC 402 contract codes and 1 44 date codes. I am playing them in my Musical Paradise MC 3 single ended integrated amplifier as I write with Aimee