I use all NOS tubes and mix. On the two center tubes I use some radiotechnique 12AU7 manufactured in 1956, the other four are General Electric 6189W. BTW, I agree with Bliss comments
Prima Luna evo300 owners
As you guys know, this integrated has 6 12au7 type tubes in front.
My question: Do you guys use identical brand tubes across the board or do you mix brands up in the same family and in a specific order to get better sound?