Coil tap
Encyclopedia
A coil tap is a wiring feature found on some electrical transformer
s, inductor
s and coil pickups, all of which are sets of wire coils. The coil tap(s) are points in a wire coil where a conductive patch has been exposed (usually on a loop of wire that extends out of the main coil body).
When the coil taps are disconnected, the coil operates as normal (see transformer
). When a coil tap is connected to one end of the coil (or the end disconnected and reconnected to the tap), the section of coil between the tap and its connected end is bypassed - effectively reducing the number of turns in the coil.
This wiring technique is said to have been pioneered by Schecter
.
Many guitarists mistakenly refer to humbucker coil splits as a coil taps, however, this is incorrect: a coil split is a humbucker with one coil removed from the wiring, leaving a single coil. Because of the ubiquity of this error, and the rareness of coil taps in general, it is difficult to find tappable single coil pickups. However, pickup manufacturer Seymour Duncan
offers tapped versions of many of their Telecaster and Stratocaster pickups on their website for a little extra money.
A Few Tapped Coil Pickup Manufacturers:
, coil taps are often used on both the input and output coils.
circuits.
or equipment input impedance
.
.
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
s, inductor
Inductor
An inductor is a passive two-terminal electrical component used to store energy in a magnetic field. An inductor's ability to store magnetic energy is measured by its inductance, in units of henries...
s and coil pickups, all of which are sets of wire coils. The coil tap(s) are points in a wire coil where a conductive patch has been exposed (usually on a loop of wire that extends out of the main coil body).
When the coil taps are disconnected, the coil operates as normal (see transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
). When a coil tap is connected to one end of the coil (or the end disconnected and reconnected to the tap), the section of coil between the tap and its connected end is bypassed - effectively reducing the number of turns in the coil.
This wiring technique is said to have been pioneered by Schecter
Schecter Guitar Research
Schecter Guitar Research, commonly known as simply as Schecter, is a US guitar manufacturer. The company was founded in 1976 by David Schecter and originally produced only replacement parts for existing guitars from manufacturers such as Fender and Gibson...
.
Musical Instruments
Single coil magnetic pickups found in electric guitars can be coil tapped to reduce the number of windings around the magnet. A tapped single coil pickup typically contains three wires: a ground, an output, and a tapped output - with the two outputs generally wired to a switch on the guitar. The guitarist can then choose between the loud, punchy, midrange-heavy sound of the entire coil, or 'tap' into the inner coil for a quieter, yet bright vintage tone with a more clear and detailed high end.Many guitarists mistakenly refer to humbucker coil splits as a coil taps, however, this is incorrect: a coil split is a humbucker with one coil removed from the wiring, leaving a single coil. Because of the ubiquity of this error, and the rareness of coil taps in general, it is difficult to find tappable single coil pickups. However, pickup manufacturer Seymour Duncan
Seymour Duncan
Seymour Duncan is a company that is best known for manufacturing of guitar pickups, and currently has a line of effects pedals. The company was founded in 1976 by guitarist and luthier Seymour W. Duncan and his then-wife Cathy Carter Duncan in Goleta, California, USA...
offers tapped versions of many of their Telecaster and Stratocaster pickups on their website for a little extra money.
A Few Tapped Coil Pickup Manufacturers:
- Seymour DuncanSeymour DuncanSeymour Duncan is a company that is best known for manufacturing of guitar pickups, and currently has a line of effects pedals. The company was founded in 1976 by guitarist and luthier Seymour W. Duncan and his then-wife Cathy Carter Duncan in Goleta, California, USA...
- Coil tapped models denoted by T following name, for example, the SSL-7 "Quarter Pound" pickup with a coil tap option would be listed as SSL-7T "Quarter Pound" pickup. - Häussel Pickups - Häussel makes a pickup based on SchecterSchecter Guitar ResearchSchecter Guitar Research, commonly known as simply as Schecter, is a US guitar manufacturer. The company was founded in 1976 by David Schecter and originally produced only replacement parts for existing guitars from manufacturers such as Fender and Gibson...
's F500T pickup, sold at MK-Guitar.com's shop. - Zhangbucker Pickups - Offers tapped versions of their pickups for an additional 15 dollars.
Transformers
In a transformerTransformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
, coil taps are often used on both the input and output coils.
- On the input coils, the taps are usually connected by switches to compensate for differing supply potential - for example, between 110 V and 230 V for AmericanUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
and EuropeEuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an mains electricity. - On the output coils, taps are used to provide a range of output potentials. Prototyping transformers are often supplied in cases which have spring-loaded contact traps - one common and several taps (for example, Common; 3 V; 5 V; 10 V.)
Inductors
Coil taps on inductors are quite rare, but are sometimes used for band switching in tuningTuner (radio)
A radio tuner is a subsystem that receives radio broadcasts and converts them into audio-frequency signals which can be fed into an amplifier driving a loudspeaker. FM tuner, AM tuner, Digital Audio Broadcasting DAB tuner, etc. are types of radio tuner dealing with transmissions using different...
circuits.
Coil Pickups
Coil pickups used with measuring instruments often feature coil taps to compensate for band rejectionBand rejection
Band rejection is a phenomenon in waveform signals, where a certain frequency or range of frequencies are lost or removed from a source signal....
or equipment input impedance
Electrical impedance
Electrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...
.
Telephone tapping
Coil taps can be used as a rudimentary method for recording telephone conversations. See Telephone tappingTelephone tapping
Telephone tapping is the monitoring of telephone and Internet conversations by a third party, often by covert means. The wire tap received its name because, historically, the monitoring connection was an actual electrical tap on the telephone line...
.