I replaced the original stock tubes with 2 x JJ ECC803-S / 12AX7 Gold pin, matched & balanced tubes, which made a significant improvement, to my ears. It sounds amazing. I did this because of a review that tested multiple tubes for this unit, and found the JJ ECC803-S / 12AX7 Gold pin tubes to be the best sounding.

It will come shipped in the original box, with a power cord, and the old tubes, in-case you ever want them. (The accessories will be packed in a bubble bag to protect the unit in shipping.)