Sorry I missed this previously. My Chime is the octal version so I use a 12ax7, a 6SN7, and a GZ34 0r Bendix 6108. In my opinion a Telefunken, Mullard, Bugle Boy or Brimar 12AX7s all work extremely well. See the comments regarding NOS tubes for the Cornet. All comments are applicable here. Enjoy