Pickup height and adjustments (single-coils)
Pickups shouldn't be adjusted too close to the strings. For single-coils, there should be about a 1/8" gap between the top of the low E pole piece and the bottom of the low E string fretted at the highest (21st or 22nd) fret, and 3/32" for the high E.
Adjusting single coil pickups any closer can cause false notes or "wolf tones." If you've ever played a Strat® that sounded like you were getting two notes from one string (usually the wound strings) in the upper registers, you have witnessed this anomaly. It is most often referred to as "Strat-itis" and can cause a lot of head scratching unless you know what is happening. To cure the problem, simply back the bass side of the neck and middle pickups further away from the strings.
First, a simple wiring diagram for a single volume and tone control, and one pickup. Once you understand the components and how they work in this diagram, you're well on your way to understanding virtually all aspects of guitar wiring.
