Meeting Photos 

On Tuesday, April 26, 2004, 38 interested people attended the PNW Section's April meeting: The Science and Voodoo of Guitar Pickups, part 2. The meeting was held at the Art Institute of Seattle and co-sponsored by the AIS Student Section.

This meeting was the second installment of three meetings dealing with magnetic guitar pickups. Evan Skop of Seymour Duncan Pickups and Jason Lollar of Lollar Guitars were our speakers for the evening. Evan took us though the variations on the various magnetic pickups and Jason demonstrated the construction of a typical Fender-style pickup.

David Christensen, PNW Committee member and AIS Student Section Advisor opened the meeting. Rick Chinn, Committee member reminded the attendees of the section's upcoming elections and of the opportunity to become a more active section member by becoming a section officer or by serving on the committee. Next, everyone introduced themselves according to a tradition established by PNW Treasurer Dan Mortensen. Daniel Casado, meeting organizer and PNW Committee member, introduced Evan.

The traditional electric guitar pickup is technically a variable reluctance design, with the string varying the reluctance of the magnetic circuit and the coil converting the magnetic variations caused by the string vibration into electricity.

There are many variables that influence the overall sound of the finished pickup. Evan admitted that while we know a lot about how to make pickups, we know much less about the science of why a particular construction creates a particular sound. A magnetic pickup is a blend of: magnet type, magnet geometry, magnetic circuit, coil parameters, pickup type (humbucker or not), and external parameters such as shielding. He passed out his company's catalog, which has a parameterized list of different pickup constructions. From this, we learned that both the type and strength of the magnet as well as the coil parameters are large influences on the sound.

The coil of a guitar pickup consists of several thousand turns of fine wire, typically between #38 and #44 AWG. #42 wire is 0.0025" diameter. A human hair is about 0.002" diameter. The coil forms an inductor, and the DC resistance of that coil (which is a function of the wire gauge and turns count), the number of turns, the winding technique, insulation type, and the winding tension all influence the self resonance of the coil, and this is a large influence on the timbre of the output signal.

Humbucking pickups have two pickup coils wired in series-opposed. This tends to reduce the sensitivity of the pickup to external fields. In addition to series opposed wiring, you can also choose parallel opposed, with a different timbre and output level as a result.

After Evan's presentation, we took a short break. Upon return, we drew for the door prizes. Four lucky attendees won.

Jason Lollar then took the mike. He explained the mechanics of pickup construction and described the different materials used. He finished his presentation by winding a pickup in front of us. 10k turns of #42 wire at about 1200 rpm. Most of us were astonished that you could wind #42 wire at that speed. Granted, he was using a purpose-built winding machine. He also showed us a considerably less elegant winding machine that would be used for so-called "hand wound" pickups.

We went into the meeting knowing that there was probably more voodoo than science involved, and the meeting confirmed that. Everyone has a bunch of recipies to follow, and they have gotten good at knowing which details they need to be aware of to get repeatable results. But it appears that nobody has really done an engineering analysis to understand what is really going on. (or if they have, they're not telling.)

Our third meeting of the series will explore the amplifier's role in creating today's electric guitar sound.

You can find an online program to help you explore the variations in tone produced by various pickup topologies at: the Seymour Duncan website. 

Reported by Rick Chinn, PNW Committee.

Last modified 4/30/2004.