What does "Out of Phase" mean?
This is of course another term that we hear often. Maybe we have replaced a pickup and experienced it... That quacky thin sound when we turn both pickups on at the same time. Most of the time it is not on purpose, although this tone does have it's place. What causes it?
In electric guitar land the term "out of phase" refers to a cancellation of sounds that happens when two pickups that have either opposite winding direction, or opposite magnetic polarity are turned on at the same time. The video below will illustrate in more detail exactly what gets cancelled. When two signals of exactly the same frequency are played at the same time, the result is cancellation. NO sound.
Fortunately for us, because of pickup placement and other factors, the frequency that each pickup is reproducing is not exactly the same. Still, a large part of the sound gets cancelled and what is left is that quacky nasal sound you hear.
How do I correct Out of Phase Pickups
When you connect two pickups in a guitar, make sure that they have matching polarity and direction of wind. This is usually not a big issue when using two pickups from the same builder, but if you are using to different brands of pickups double check the documentation so that the wiring is correct. If you are not sure, you can carefully (so they don't short) leave the leads exposed and test the guitar with both pickups on. If it is out of phase, just switch the leads of ONE of the pickups. (if you do both, you are right back where you started).
The Exception to this would be a pair of pickups that is wound as a set to be hum cancelling when used together. This is a result of one pickup being wound RWRP (reverse wound reverse polarity). We will discuss this in an upcoming blog post.