#1
What happens or what does it mean when a pickup is wired and in:

Series?

Split?

Parallel?

(In/or out of) Phase?
#2
Series is standard humbucker wiring, highest output of the three.
Split is using one coil of a humbucker, sounds more single coilish.
Parallel is wiring the two coils of it in paralled, similar to having two pickups on in a strat, lowest output of the three.

A pickup in phase is normal, pickups out of phase with each other sound thin and trebly.



#3
Series is typically how humbuckers are wired, its when the north side (referring to its orientation on the magnet) of one coil is connected directly to the south of the next coil.
Parallel is when both coils are active, but arent connected to each other.
Split is one coil used only.
In-and out of phase; picture the output of a pickup (or coil) as a sine wave (for simplicity) If the wave is the same for both coils or pickups, they are in phase. If you flip the wave for one horizontally, they will be out of phase with each other.
#4
I have a set of GFS rail humbuckers in my strat copy with 3 DPDT on-on-on switches. Each switch lets me set each pickup to series/parallel/coil split. I wired the middle pickup out of phase and wired my 5-way so it goes bridge, bridge+neck, neck, neck + middle out of phase (really squawky bluesy sound) and middle. It gives me a great range of tones. The pickups are also rather sensitive to height, so I have my bridge pickup raised high and in series mode, it has the highest output and it will really push an amp. Switch to the neck in parallel mode and I can get cleans from the same amp setting.
Lefty Strat Copy w/ GFS Lil' killer rails + Crazy wiring
Lefty Kona Thinline Acoustic/Electric
Righty-to-Lefty Silvertone Bass
Righty-to-Lefty Memphis Short Scale Bass
Vox AD30VT-XL

Tascam US-428 USB Interface Mixer
Guitar Rig 3