Well I installed shielded cables on every connection and set it right.
After taking a read on the MN3007 datasheet, I've discovered a great graph: THD vs Vbias!

That's saying that the lowest distortion is @ -8,1V bias (#3 ofc).
I've set clock ~69KHz and level in order to eliminate the regen feedback.
The pedal itself sounds good, but that crackling noise is still present. It is subtle, but it's there.
When I put the width at min, I get a little "speed" noise. More and more I turn the Width pot, whilst regen is not at minium, that crackling issue comes up.
Fender3D, I read that you installed the AD/A noise gate into the MXR. What's that all about?

Actually I start to think it's a MN problem. This one comes from a lot of 5 I bought 2 years ago from ebay - Honk Kong.
1 of that lot was WAY distorting and throwed it. 1 is in my CE2 clone, another has gone in another CE2. 1 is this one I'm using and the last has been thrown in the bin just a few days ago because was dead! No signal on output!
Whatcha think?