The tube of choice for this preamp is Amperex Bugleboy. Any Amperex 6DJ8/6922 will sound good. Mullards also sound good. Be sure you get NOS tested and matched as this pre does not like any microphonics from the installed tubes. None of the current production tubes will sound as good. Believe me I have tried them all.
best tubes for Audible Illusions M3a
I'm wanting to replace my tubes, and, am wondering what other owners have found to be the best tubes for this pre-amp.