http://www.mullardtubes.com/Video.aspx
personally, ive tested A/B old NOS tubes 12au7 12at7, from GE and others vs. the new sovtek 12ax7a, and the new sovteks sound better to me.
analized the harmonics and noise floor with izotope ozone, and mda vst free plugins. with sine tone at arround 50hz.
the new sovtek ax7a has lots more harmonics, than au7 and at7.
it all depends of you like color sound or grey sound.
i like color, anyway.
personally, ive tested A/B old NOS tubes 12au7 12at7, from GE and others vs. the new sovtek 12ax7a, and the new sovteks sound better to me.
analized the harmonics and noise floor with izotope ozone, and mda vst free plugins. with sine tone at arround 50hz.
the new sovtek ax7a has lots more harmonics, than au7 and at7.
it all depends of you like color sound or grey sound.
i like color, anyway.