Thanks for that great explanation. You and I are cut from the same cloth. I spent years with a cj MV-52 then an MV60 and totally came from EL34 listing paradigm! I value the mid-range over everything. If it's not correct I don't care about anything else. I have voiced my system around the v4s with the KT150s, and I think the rest of my system makes them a little more mid-range wonderful, but it may be due to system balance not due to the tubes. I just bought a shunyata Everest which opened up dynamics and clarity. I think it would be really interesting to try the KT-120 tubes. I will think about that! Not sure whether trying to upgrade from mundorf Supremes in my v4s is worth it?
Thanks
Stu