I was bored one day and took apart my Carvin R600 head and found a sovtek 12AX7 preamp tube in it. Then I took apart my Digitech BP8 and found a Sovtek in that too. I know close to nothing about tubes and was wondering if these are good tubes or if I could get a better sound out of better tubes. If anyone has suggestions please let me know. woohoo! I just realized I become a senior member with this post.