GuitarElectronics.com Glossary

Guitar electronics terms as defined by pickup master Seymour W. Duncan.

Active Pickup - A pickup using an electronic preamp to achieve gain enhancement, tonal shaping and/or output impedance reduction. Some advantages include less susceptibility to noise, greater flexibility in creating new tones and the elimination of high frequency losses caused by driving long cables. Active pickups can be particularly useful for producing the strong noise free signal needed to drive multi-effects racks. (For comparison, see "Passive Pickup").

Amplifier - A device for making small electrical signals bigger. The amplifier was actually invented in the late 1800�s before there were any devices that could make building one possible! In music, the term often refers to a self contained �combo amp��-an electromechanical device combining a preamp, amplifier, and loudspeaker usually including some kinds of tone shaping circuitry. With Solstice, you have the option of �custom building� your amplifier by matching the preamp/mixer/blender stage to a separate power amp and loudspeaker system.

Buffer - A preamplifier designed to isolate the source from the next stage of amplification. Buffer amps have high input impedances and low output impedances and can also feature some �gain� or signal boosting capability. Buffers are required with piezo crystal or piezo polymer pickups, and are often built into acoustic-electric guitars. Solstice features high impedance buffer stages for both channels so you can use either active or passive pickup systems. D-TAR makes several on-board buffered pickup systems for acoustic instruments.

Calibrate - The winding of each pickup in a set differently in order to produce a balanced output level when switching from pickup to pickup.

Contact Pickup - Or �soundboard transducers� are most often piezoelectric accelerometers (acceleration monitors). They put out an electrical signal that is an electrical equivalent to the mechanical vibrations occurring where they are placed.

DC Resistance - The resistance to the flow of Direct Current. For most pickups, it is a very general indicator of the output and tonality with higher DC Resistance tending to be higher in output and less bright.

DI (see also �Direct Box�) - The British term now common in the US for �directly interfacing� a pickup signal into a recording or PA console, thus bypassing amplifiers, speakers, and mics. Used especially for electric bass to get a clear tone. Many home enthusiasts directly connect their acoustic guitars to the recording device to gain better isolation from track to track than they can get just using microphones. Many preamps have XLR outputs to allow using it as a DI source.

Direct Box - A device used to buffer or isolate guitar and bass signals so they can be �DI�d�. Many of the direct boxes designed for electric guitars and basses do not have a sufficiently high input impedance for interface with piezo pickups. Direct boxes can either be passive, using transformers, or active, using tube or transistor based circuitry.

Distributed Capacitance - The capacitance which exists turn-to-turn and layer-to-layer between the wires of a coil. This property combines with the coil's inductance to produce a resonant peak. Post resonance, distributed capacitance acts like a built-in tone pot and rolls off high frequency response. (See "Resonant Peak").

Effects Loop - A set of jacks on an amp or preamp which allow sending a signal out to an effect and bringing the modified sound back to the main unit. The advantage of an effects loop is that it is buffered (yes, same concept) on the output and input, the effect will �see� a predictable impedance and level, and the modified signal can be master volume controlled in the main amp or preamp.

Epoxy Potting - A method of sealing a pickup in epoxy to reduce microphonic feedback and protect the pickup from damages due to handling, exposure to the elements and normal use. (See also "Wax Potting").

Equalization or EQ - An electronic means of shaping frequency response; the term generally refers to sophisticated tone control circuitry. Originally used to mean correction for the unequal frequency response of old PA, recording and playback gear.

External Mic - Generally referring to the good old practice of standing in front of a mic on stage as opposed to installing a mic in your guitar. You�ve seen them, you�ve used them, and now you know what they�re called. There are now some bracket devices for mounting an external mic on your guitar.

Feedback - It happens when amplification goes beyond control, and the amplified sound itself is re-circulating and becoming further amplified. The sonic equivalent of Chernobyl�-audio meltdown. �Ringing� is the precursor of feedback and refers to a barely controlled resonance just shy of feedback.

Floating Pickup - A magnetic pickup mounted to the end of the fingerboard on a guitar or to some other non-vibrating part of a musical instrument. Floating pickups are sometimes used on arch top acoustics so the adding of a pickup will not interfere or change the vibration pattern of the top. Seymour Duncan makes a variety of floating pickups including the Bob Benedetto signature pickup for use with arch top guitars.

Four Conductor Pickup - Pickup with independent termination of the beginning and ending leads from each coil of a humbucking pickup to a cable with a common shield. This approach allows much versatility in wiring and switching configurations, i.e., series/split/parallel, splitting with coil selection, in/out of phase with itself, in/out of phase with another pickup, etc.

Gauss - The CGS unit of magnetic flux density used to describe the field strength of a magnet.

Graphic Equalizer - An equalizer that uses sliding potentiometers (slide pots) to control the level of the signal in various frequency bands. Called so because the knobs form a graphic representation of the frequency contouring. Graphic equalizers are generally either �1/3rd octave� or �1/10th octave� referring to the width of the audio bands covered.

Ground - A common reference point in an electrical circuit.

Hum Canceling, Humbucking - A pickup design consisting of two coils which are summed electrically out of phase and with magnetic polarities reversed. The effect of the configuration is to cancel hum and other extraneous noise and leave the string signal perfectly intact.

Humbucking Pickup - A type of pickup using two coils to cancel magnetically induced hum. Invented by Seth Lover at Gibson in the 1950�s, the �humbucker� is noted for it�s loud and warm sound.

Impedance - A measurement of the resistance to the flow of AC (which is what audio signals are); impedance is affected by resistance, capacitance, and inductance in a circuit and is also frequency dependent. Impedance is often mistaken for resistance and is also incorrectly thought of as being a measurement of the voltage from a pickup. In practical terms, you want low impedance sources feeding into high impedance loads; this gives maximum accuracy in signal transfer. In passive pickups this figure is variable with frequency.

Inductance - The property of a coil to oppose changes of current through itself.

Internal Mic - A microphone, generally an electric condenser mic, mounted inside an instrument.

Line-Level - The voltage level at which most pro gear sends pre-amplified signals to other devices such as equalizers, limiters, compressors and power amplifiers. Generally considered to be +4(dBm) or 1.2 Volts RMS.

Magnetic Pickup - A pickup that consists of a magnetic structure and one or more coils of very fine wire which �transduce� or transform the vibration of plain steel or steel cored wound strings into an electrical signal.

MIDI - Musical Instrument Digital Interface, the computer language used in modern synthesizers and signal processors to �communicate� with other devices.

Milli Volt - One thousandth of a volt. (mV)

Ohms - The standard unit of electrical resistance.

Out Of Phase - The electrical linking of two coils or two pickups in either series or parallel but with the signal polarities summed in such a way as to provide at least partial cancellation of the signal. Usually the low frequencies are canceled so the resulting sound is thin, lacking in warmth and often quite brittle.

Parallel - The electrical linking of two coils in a parallel or side by side fashion. The sonic effect compared to a series configuration is approximately 30% lower output but with additional brilliance and clarity on the high end. (See "Series").

Parallel Axis� - A Seymour Duncan patented pole piece system that utilizes four separate small blades per string. The blades are arranged in a configuration that decentralizes and softens the magnetic field providing smoother highs and greater sustain while minimizing distortions induced by string pull.

Passive Pickup - A type of pickup which uses no internal active electronic circuitry. (See "Active Pickup".)

Phase - The relationship of two wave forms with respect to time.

Pickup - Any device that changes vibrations of a soundboard or strings into an electrical signal. The most common pickups are magnetic and piezoelectric.

Piezo Pickups & Piezoelectricity - Certain crystals, ceramics, and polymers exhibit the phenomenon of piezoelectricity. Piezo means pressure in Greek, and piezo materials directly transform mechanical vibrations into electrical signals. Most under-saddle pickups, are based on the piezoelectric effect.

Polarity - The relationship of positive and negative electric currents (or North and South magnetic poles) to each other.

Pole Piece, Non-Magnetic - A ferrous (containing iron, magnetically conductive) metal piece used to control, concentrate and/or shape a magnetic field. Although many styles have been used, pole pieces fall into two broad categories of adjustable and non-adjustable.
At Seymour Duncan, we currently use many different types of adjustable and non-adjustable pole pieces. The physical configuration of the pole piece will vary the magnetic field intensity of the pickup. Generally a more massive pole piece, such as the button head cap screw used in the SH-8 Invader�, will produce a stronger field. This gives higher output and a more aggressive attack. Smaller or thinner pole pieces tend to produce a lower field intensity giving reduced output and a smoother attack. It is possible to combine two or more types of pole pieces in one pickup in order to achieve a subtle balance between attack, definition, and fullness.

Pole Piece, Magnetic - Refers to a pickup in which the axis of the magnet is aimed directly at the strings and the magnet itself is serving as the pole piece. This design approach is most commonly used on vintage single coil pickups where cylindrical rod magnets serve as pole pieces, however, bar magnets have also been used in this application.

Potentiometer, Pot - Refers to a resistor with a center "wiper" that sweeps from one end of the resistor to the other. Commonly used for volume, tone and other functions.

Preamp - An electronic device usually designed for matching low-level signals to a power amplifier. EQ and other signal processing is usually done with or within the preamp stage. Solstice is a preamp in addition to being a mixer-blender.

Presence Control - A section or knob of an equalizer operating in the upper midrange.

Processor - Any signal-modifying device often combining several effects such as
EQ, chorus, delay, and reverb. You can use processors with Solstice by inserting them in the effects loop(s). Digital multi-effects units are commonly used for modifying guitar tones.

Rack Mount - Gear that is designed to be mounted in the international standard 19� �relay rack�. The standard was set by the phone company for its racks upon racks of electrical switches that routed phone calls in days of old when phones had dials and dial tone really meant something.

Resonant Peak - The frequency at which the impedance of a pickup is at its highest. Within a given category of pickups. a higher resonant peak usually indicates a brighter, clearer sound.

Ribbon Mic - A type of microphone in which a very thin conductive ribbon, usually aluminum, vibrates in a magnetic field. A small current is induced in the ribbon itself and is then preamped like other types of mic signal.

RW/RP - Stands for Reverse Wind/Reverse Polarity. Refers to the practice (originated at Seymour Duncan in the late '70s) of reversing the winding direction and magnetic polarity of one single coil pickup from a two or three pickup guitar. When this is done, hum cancellation can be achieved when using two pickups together.

Scatter Winding - First, let's define some terms. "Machine Winding" - a machine spins the bobbin and moves back and forth at a regular pace, distributing the wire evenly across the bobbin. "Hand Winding" - a machine spins the bobbin, but the magnet wire goes through the hands of an operator who distributes the wire along the bobbin. This is how the earliest pickups were wound. "Scatter Winding" (Also called "Random Wrap") - a machine spins the bobbin, and the magnet wire goes through the hands of an operator (named Seymour) who distributes the wire along the bobbin in an intentional scattered or random pattern. All scatter wound pickups are hand wound. Not all hand wound pickups are scatter wound. Scatter Winding has a few effects on a pickup's tone. First of all, when you scatter wind a pickup, you�re not placing the wire as close to itself on each layer as you would with a machine. The effect is to create more air space in the coil. This lowers the distributed capacitance. The best way to think of distributed capacitance is like a little tone control in the pickup. When the capacitance is lowered, the result is that more treble will come through and the resonant peak of the pickup will increase slightly. Secondly, each scatter-wound pickup will sound slightly unique. You can scatter-wind ten pickups with the same wire and number of turns, but each will sound different.

Series - The electrical linking of two coils in a serial fashion producing a higher output, fuller and more powerful sound. This is the standard hookup for humbucking pickups. (See "Parallel").

Signal - In amplification, the signal is the electrical analog of the musical note(s) traveling through the amplification chain.

Single-Coil Pickup - Refers to the simplest style of magnetic pickup having one coil of magnet wire. Noted for a certain clarity and focus. Seymour Duncan is famous for it�s recreations of the most famous single coil pickups from the �golden era� of magnetic pickup design.

Splitting, Split Pickup - The process of grounding out one of the two coils of a humbucking pickup thereby producing a single coil sound. (See, for comparison, "Tapped Pickup").

Stack� - Seymour's patented technique of stacking two coils, one above the other, in order to cancel hum and noise but retain a single coil tonality.

Tapped Pickup - A coil which has two or more hot leads exiting at different percentages of the total wind in order to provide multiple output levels and tones. (See "Split Pickup").

Three-Band EQ- Refers to types of equalizers having low, mid, and high frequency controls.

Transducer - Any device that changes mechanical or acoustic energy into an electrical signal or vice versa. (i.e. a pickup converts kinetic motion into an electrical signal, a speaker converts an electrical signal into kinetic motion). Mics, pickups, and loudspeakers are all transducers. The term transducer is often used with accelerometer style piezo pickups, but is not exclusive to such pickups.

Transient Response - The quality of how fast a preamp, amplifier, or signal processor responds to an input signal. Related to �slew rate�. Fast is good, slow is bad.

Trembucker� - A humbucking pickup designed with wider pole-to-pole spacing in order to accommodate guitars with vibrato systems or wider string spacing.

Volt - The practical unit of electromotive force, the pressure which causes a current of one ampere to flow through a resistance of one ohm.

Wax Potting - A method of saturating a pickup in wax to hold the coil and any mechanical parts absolutely rigid. This is done to prevent undesirable microphonic feedback. At Seymour Duncan we use a custom made vacuum encapsulation system to insure thorough wax penetration.