Go for it - and sometimes the more expensive tubes don't necessarily sound better than lower cost alternatives. It really depends on how
you want to fine tune the sound.
Typically, you can go more open, detailed and extended sounding compared to the stock tube. More dynamic and lively
OR- warmer, richer, and sweeter with "fatter" tone compared to the stock tube.
It gets a little tricky to find tubes that can do all of this, though.
Welcome to the RWA forum and Audiocircle and viva la Signature 70.2 LFP-Vs! I'm glad you are enjoying them, and cryo Gold Lions
do sound great with them. They really open up the sound with the 70.2s.
Have you compared the 1960s French Madza tube to the Miniwatt Dario E188CC (France). I wonder how similar they are. It would be nice to find some tubes that are very close to or essentially the same as the MD (just like the Amperex 8416 PQ sounds the same as the Amperex 7308 PQ, but with a 12V heater).
I still need to listen to more NOS 12AX7s. In the Cassabria headphone amp, I'm actually having a hard time pulling out the stock JJ 12AX7 (ECC83). It just sounds so right in there from top to bottom - I don't know why, but it does!!!