EpiActive
Pickups
Welcome back to Dr. Epiphone’s
Guitar Lab. The good Doctor and his trusty technicians have been hard at
work bringing you another Epiphone innovation in tonal excellence. This edition
of the guitar lab will feature the design and technology behind the new EpiActive
pickups.
To understand how an electric guitar
pickup works it is necessary to take a look at some basic electromagnetism.
The basic theory behind all magnetic pickup operation is Faraday’s law
of induction. In simplistic terms this law states, among other things, that
a changing magnetic field will induce a voltage in a coil of wire that is
properly positioned within the magnetic field. The basic construction of
a typical magnetic pickup is shown here.
 As the string vibrates the flux of the pickups magnetic
field is altered and a voltage is induced within the wire that is wound around
the magnets. This voltage follows the frequency of the vibrating string and
increases or decreases as the string is struck harder or with less
force.
Characteristics of tone associated
with traditional magnetic pickups are determined by the number of turns,
wire gauge, and magnets used. Due to complicated electrical relationships
all pickups have a resonant frequency that characterizes the sound of the
pickup. There are always trade offs when designing pickups in this manner.
Pickups designed for high output sacrifice high end frequency response. Pickups
that have more top end response typically have a lower output. Designers
are very good at minimizing these compromises but they still exist to some
extent no matter how clever the design.
To overcome some of these design
limitations and provide a wider range of tonal options Epiphone engineers
for the last several months have been locked away in the lab devising the
next great Epiphone pickup. The result of months of research and development
has been the creation of the new EpiActive pickups.
Using state of the art
“active” circuitry Epiphone engineers have been able to provide
uncompromised tone and output. By utilizing a built in preamp circuit it
is possible to overcome many of the design limitations of traditional passive
pickups. Active pickups are so named because of their use of a battery supply
to power electronic components within the preamp. This allows the designer
to not only cut frequencies but also to boost desirable frequencies within
the bandwidth of the pickups output.
The preamp circuit used on the new
EpiActive pickups features ultra low noise and low distortion audio op amps
and state of the art surface mount components. By utilizing an active preamp,
frequency shaping circuitry has been included to maximize the tonal potential
of the pickups output. In addition to the ability to control and shape the
tonal output of the pickup the preamp also provides the ability to boost
the output signal level beyond what is possible with passive pickups. The
EpiActive pickups provide a wide bandwidth, high output dynamic signal that
is perfect for screaming harmonics and ultra crisp chord definition. A picture
of the preamp circuit before being installed into the pickup housing is shown
below.
The pickup coils and preamp are
all contained within a fully shielded housing to provide excellent noise
immunity. Each of the EpiActive pickups has been custom voiced to provide
the optimal tonal response for either the neck or bridge positions. And unlike
many other active pickups on the market the EpiActive pickups also provide
the option of passive operation to give you an even wider palette of tone
to choice from when a more vintage output is required.
The results from the lab are in.
Dr. Epiphone and his team of technicians have once again succeeded in creating
an outstanding pickup of uncompromised quality and tone.
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