Bartolini pickup’s coil placement and magnets

Bartolini pickups are used on various basses from reasonable to high-end models. Although they are often used as replacement products, they have a unique mild and wet sound, and there are many enthusiastic fans worldwide. This time, I would like to write about the internal structure of Bartolini pickups. This time, I will focus on only Jazz Bass pickups and soapbars, and will not write about Precision Bass pickups.

● Single coil

This is a very standard type. Polarity for jazz bass pickups is opposite between neck and bridge, generating less noise when blending two pickups. Many Bartolini magnets are blade type magnets, and in this case, the lead wire is wound around one magnet to make one coil. I like blade type single coil pickups because I don't have to worry about the pitch between strings.

● Dual coil

As shown in the picture above, the wire is wound around each blade magnet, and the two bobbins are confined in the cover. The big difference between the single coil and dual coil is that you can get a noise canceling effect with only one dual pickup, as there are two coils in one pickup and each has opposite polarity.

● Quad coil with four magnets that have opposite polarity across neck side and bridge side.

Dual coils are common for normal humbuckers, but the quad coil has four magnets. The neck side and the bridge side have opposite polarity. Similar to a dual coil humbucker, but tends to provide a wider range using two bobbins with the same magnetic pole.

● Quad coil with four magnets of different polarity between bass side and treble side, and between neck side and bridge side.

This is confusing. It's hard to put into words, but the coils have the same magnetic poles as the coil diagonally across from it. A wide variety of sounds can be created in parallel wiring, and noise cancellation and high output are achieved even in the series wiring. These quad coils are also applied for the MM type.

● Split coil

At first glance, it's a humbucker, but it's actually a split coil type inside. It is designed to be noiseless and pick up the widest possible range of string vibration while saving space compared to the quad coil pickups. Like the Precision Basses, it’s very easy to control the tone but output is high.

● Single coil diagonal arrangement

It's similar to a split coil, but it’s a single coil set in a diagonal arrangement, which is a simpler mechanism. Mixing with the neck and bridge will have a noise canceling effect.

● b-axis

This also has a dual coil structure. The magnet in this series is Alnico5, which is rare for Bartolini, and they have a vintage atmosphere compared to others. The diagonally arranged magnets can capture string vibration in detail. Since it’s a dual coil, it cancels noise.

At first glance, a single coil may actually be a quad coil, or vice versa. By the way, Bartolini's original cover, with an internal structure that is difficult to understand, is a coil encapsulated in epoxy. It is completely shielded to eliminate the noise generated when touching the pickups.

Bartolini pickups provide a stable sound by using ceramic magnets and the noiseless structure. The variety of sizes makes them highly flexible, which is probably the reason why Bartolini is selected for a wide variety of basses.

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