I've got basically the same setup, PL2 with the Tube Box SE II. The previous owner of the PL2 sent a matched set of EL34's and some Mullard 12ax7's with it. I wasn't real fond of the EL34's in the PL2. I tried the Mullard's in the PL2, but that wasn't right either. I then switched the stock tubes in the Tube Box with the Mullard 12ax7's.... That was it. I'm currently running a matched quad set SED winged C's in the PL2 with the stock smaller tubes.