I am selling a pair of these lovely tubes from my collection. I have owned them for 10 years and they test as new, I have tried them in my Audionote M8 preamp and they are extremely quiet no microphony at all. Matched pair Amperex long plate 17mm, D-foil getter, Top seams. Originally labelled Beckmann but label is now mostly erased These have the CT0 marking etched into the glass designating them to be the 7316 variant Tube 1 Delta 8K 1958 Tube 2 Delta 8I 1958 As measured on my VCM 163 tube tester Ma and Gm for each section shown below Tube 1 A1 10ma; A2 11ma: A1 2ma/V; A2 2ma/V Tube 2 A1 12ma; A2 11ma: A1 2.3ma/V; A2 2.2ma/V Where new tube is 10ma gm 2.2
eBay