6418 tube microphonic ?

[jonathan9473]

hey guys! I am building a phantom-powered tube microphone(frankentube ) and I have tried many ways to reduce the microphonic ring sound. At first, I thought it could be a bad tube, then I tried 6 more tubes but the problem is still there . Then I saw Kingkorg's way so I shorten the lead then use soft wire to connect, it reduces the noise alot but not completely. Do you guys know anymore ways to reduce the microphonic noise? Or should I use another tube, are there any 6418 tube equivalents?

Thankyou