I noticed long time ago that I can't get clean tones with some guitars. It is always a little distortion, even with ultraclean tones.
Curiosly, active pickups (Emg, Blackouts) sound totally clean but pasives (SH6, Nazgul) sound distorted. Weird.
Listen to this clip, first part is Blackout (active), second part is Nazgul (pasive).