Hi, Does anyone know if the Fender Vibro-King has a cathode follower stage, and if so, what preamp tube affects it? I like the new Tungsol reissue 12AX7's but keep blowing them in my V-K V4 tube position. If I use a Sovtek tube, I have no problem. I saw on the KCA tube website that the Tungsol's are not to be used in cathode follower stages. I'm curious if that is my problem. Appreciate any help I can get.