Test polarity of magnets in a pickup

North of south?

With the help of a magnet you can find out whether a guitar element has the north or south pole at the top. In some humbuckers, you can determine which pole has the side with the screws. But why would you want to know this?

For example, first think of connecting (replacement) elements, where you want to prevent them from being out of phase unintentionally. You may also want to find out if two single coil pickups can form a humbucker when both are activated. The poles must then be mutually "inverted". A principle that you increasingly encounter.

Another important reason may be that you include this extra check in the general check on the originality of an instrument. Depending on the year of manufacture, the poles pointing upwards may have changed in the meantime. For example, the Fender Telecaster bridge element initially had the south pole above and the neck element the north. In the mid-1950s the magnets were also placed in the Telecaster neck element with the south side up. An original Gibson P90 always has top south. And a Gibson P.A.F. humbucker has the south poles on the side with the screws. On the internet, such details can be found per guitar and per type of element.

You can test this with the aid of a separate magnet, the poles of which you know. Is your test magnet attracted to the magnet in the element or is it repelled? However simple, such test magnets are for sale. For example, the tester you see here, where a magnetic disc with the white or black side faces up when you hold it above a guitar pickup. In the photo you see the disc in the top left of the plastic tube. White means north at the top, black obviously so south. The whole is less than 10 cm long, you do not have to disassemble anything in the guitar and it turns out to be quite handy in practice.