A BRIEF DESCRIPTION OF PICKUP MAGNETS:
Fender guitar pickups typically use Alnico magnets in their construction. Alnico is an alloy that is a combination of the elements Aluminum, Nickel and Cobalt. As the amounts of each element are altered within the magnet, so is the magnets overall strength. This is what accounts for the difference in sound on various pickups.
The magnets itself is not the source of the pickups tone, as there are many other factors that contribute to this, such as type of wire, number of winds, etc. The magnets job is to transfer the strings vibration into a signal that comes out of your guitar and goes into the amplifier.
Here are the most common types of Alnico Magnets:
Alnico 2 magnets can be characterized as richer, looser and warmer. They don’t have the typically bright highs that are most often associated with Fender single coil pickups but do have nice mids. They are well suited to bridge pickups as they give a good punchy, tight sound ideal for rock style., Although they can be used for neck pickups as well, they can tend to get a bit dark and splashy.
Alnico 3 has the lowest strength of all the Alnico magnets. Like the Alnico 2, it has more treble, scooped mids and a tighter low end, but not perhaps as brassy as an Alnico 2. Good magnet for neck position pickups, very woody and clear sounding. This magnet was used more frequently in Fender’s early days.
Probably the least used magnet in Fender pickups today, Alnico 4s are very flat and tend not to add or color the tone and let the guitars natural wood tone come through. Think more guitar, less pickup as far as sound goes. It kind of fits between a 2 and 5, brighter highs than a 2 and more full-bodied lows than a 5. Some describe the sound as kind of generic and non-remarkable in Fender guitars, but seem to do well with some humbuckers and larger bodied guitars.
Alnico 5 is the strongest of all the magnets and the most commonly used in Fender guitars. It generates more output, good, tight low end, scooped mid-range and that classic Fender high end. While not as tight and punchy as an Alnico 2, the Alnico 5 pickups tend to be lower wound, giving that good balance of highs and lows that makes Fenders sound the way they do.