Welcome to the TBC Club - The scratchy blend pot happens to be their Trademark!
I have 2 of 'em and they both do it. I tried cleaning them but neither cleaned up. Must be a defective batch of pots. They might send you a replacement preamp, but I'm not sure I'd bother as it will most likely be defective as well. Mine were.
Normally this would be an easy fix (to just swap out the blend pot) but their blend pot is a proprietary design with an IC board attached and has what looks like shielding wires attached to the pot with a modular clip to the IC board that go back to the Black box. I've been meaning to try a normal pot and simply grounding those wires to see if that works. I'll try it in the next few days. Although, I'm real close to trying an Audere pre in one of mine, that should fix it! Haven't been in a hurry as the stock pre sounds pretty good.
Not clear on your panning issue - Are you saying that the center detent is not centered visually? If that's the case, just open up the control cavity and twist the pot internally to correct it. Once corrected, take the knob off and tighten the nut while holding the pot secure on the inside...
Or is it that sonically your neck p/u is prominant when the blend pot is in the center. If that's the case are you sure your neck p/u isn't considerably closer to the strings? And, bridge p/u's placement naturally receive less vibration from the strings and (in most cases) should be closer to the strings for a more even response w/the neck p/u.
HTH
