For a cheap, if not final, choice you might try some new production Mullard 12AX7's. I found that using them in my Primaluna's help solve some of the issues in the mids and highs.
FWIW I read comments about the 120's which suggested to me that your problems are more likely caused by your choice of power tubes. I use Tung-sol 6550's in my Dialogue Two (with Tung-sol 12AX7's) and Sovtek KT88's in my Dialogue One (with the Mullards).
Of course I have different equipment, speakers, room, and most importantly ears. Good luck in your search.
FWIW I read comments about the 120's which suggested to me that your problems are more likely caused by your choice of power tubes. I use Tung-sol 6550's in my Dialogue Two (with Tung-sol 12AX7's) and Sovtek KT88's in my Dialogue One (with the Mullards).
Of course I have different equipment, speakers, room, and most importantly ears. Good luck in your search.