I have the same or similar amp (mine is the Signature), here is what I am currently using.
GL KT88 reissue power tubes
TS 12AT7 cryoed p-splitters
Baldwin branded 12AX7
I also tried the new GL12ax7, more of a sweet tubey sound. I prefer the Baldwin AX7's sound, more 'neutral' balance.
TS12ax7 (cryoed)+TS12AT7(cryoed) + GLKT77 was the ultimate balance for my taste. Excellent midrange, clean highs, and solid punchy bass. If you go this route request "hotter biasing' GL KT77 quads from your tube dealer, I rec. Jim McShane for the power tubes.
I got the cryoed tubes from Cyroset.
YMWV
GL KT88 reissue power tubes
TS 12AT7 cryoed p-splitters
Baldwin branded 12AX7
I also tried the new GL12ax7, more of a sweet tubey sound. I prefer the Baldwin AX7's sound, more 'neutral' balance.
TS12ax7 (cryoed)+TS12AT7(cryoed) + GLKT77 was the ultimate balance for my taste. Excellent midrange, clean highs, and solid punchy bass. If you go this route request "hotter biasing' GL KT77 quads from your tube dealer, I rec. Jim McShane for the power tubes.
I got the cryoed tubes from Cyroset.
YMWV