Thanks for the info. So, do you still use 12AX7's in the other stages of your boogies?
I also have a NOS Mullard 12AT7. I found it too mellow for another el-84 based amp. I should try it in the MKII at V1.
Interestingly, I have put other (new) 12Ax7's in the V1 position of the MKII and found...