Looking for brighter tubes

You'd probably find the NOS German tubes to be your best bet (Telefunken or Siemens).

You should consider changing the four.22uf coupling capacitors and the two .47 capacitors. They are made in China by CBB and they are dirt cheap. That is why they use them. Not for their sound. Good for their price but easily outdone.

Siemens E81CC or ECC81 have nice extension.

the weak link in this amp are the coupling caps. don't waste money on tubes till you fix the caps followed by a power supply upgrade.

Not sure about the power supply but the caps were Maryland Jolida upgraded (along with other items in the "upgrade" mod version). The 12AT7s currently are EH Russians (the only non-Tung Sols).

The amp is new-ish (newest version actually, and supposedly improved over older versions), I haven't tried any other tubes in it yet, but so far it sounds great (quiet, looks cool, very well built, sweet tone). I'm not complaining, just fishing for info among my fellow tubists. Tubers? Tuboids? Bottle Heads? Valvers? At the current price for these new, I'm surprised everybody doesn't own one just to play with the damn thing. It's fun. I appreciate the suggestions...keep 'em coming.

Agree re the Telefunkens; my favorite tubes of the 12at7 and 12ax7 variety. I would like to add a comment about the perception of spectral balance that you might find useful. Notice also the comment about the great midrange of the Tele's. I completely agree. To me the Tele's are the most refined (real like live) sounding tubes by far. But their full sounding midrange and bass in my system can sometimes create a perceived net effect of less brightness. Just food for thought. When I think "more zizzle" (but still pretty good overall) from MY stable of tubes IN MY GEAR, I think Phillips Miniwatt SQ 12at7, and Sylvania '60s vintage green label JAN 12at7, and Raytheon 12ax7 black plate.