obsidian- crossover distortion?

[Quackzed]

I've noticed that my obsidian build has a wierd 'ghost note' that fizzles out as i let a note ring out... i'll play a strong open g string or something, its distorted then  it fades from distorted to clean rather oddly, the distorted character kind of fizzles then zzzp its clean...
i also noted that the louder i turn the volume knob, the cleaner it gets! It's most noticable with low gain settings.
I love the high gain sound, i was just wondering if this is indeed crossover distortion?
and if so, is there anything i can do to try and get rid of it?
or maybee it is just a quirk of the design?
my bsiabii has the similar quality that it gets a bit cleaner at full volume, but the clean/distortion transition is smoother..
anyone hear a similar thing with any of their obsidian builds or have any ideas what might be going on?

[WGTP]

I added 2 anti-parallel GE diodes in line between the 2nd and 3rd stages for deliberate crossover distortion, and don't remember it sounding like that.  Have you measured the voltage on the drain of the mosfets to see if it is around 4.5v?  I'm wondering if the bias is correct on all 3 stages.   I don't think I used the stock resistors to get the bias correct.   

[Quackzed]

hmm.. i seem to remember having trouble getting the first stage to bias right when i put it together... actually it does sound like gating. i'll have to take a closer look at that first stage bias setup...