Hi, I recently aquired an older 2 channel DR head and have some questions. To start it sounds lifeless and seems to be lacking gain and sounds a bit thin. I used to own a multiwatt and a single a while ago and they seemed to have way more punch. Would it be worth swapping the tubes out, they are Mesa 6l6GC str 430 and look like all mesa 12AX7's also. I have it going into a mesa 2x12. Also just to freshen my memory as I can't recall with the other Rectifiers I owned but with the channel volume off is it normal to still be able to hear the guitar?