At last time has come to check GL KT88 in my Muzi x7. Amp had very good sound with original chinese KT88, even better sound was when I started to use Mullard KT66 new, I even could not understand how sound could improve with another KT88. But when yesterday I put in GL KT88, I was really surprised - all good things of Mullard has remained but all started sounding somewhat more "delicate", with more finesse, all became more "musical"... Now I have three different but all very good KT88s which I will use with different rectifiers (to get slightly different but very good sound).
Thnx to audioph.fr for all this.