Pickup Wiring Options

In this article, Pete Biltoft at Vintage Vibe Guitars gives an in-depth explanation of pickup coil wiring options.   Note this information is provided in the context of humbuckers, but applies just as well to a pair of single coil pickups that are RWRP relative to each other.     You may also find my earlier posts useful:  Humbucker Wiring and Coil Splitting, and Pete’s previous article on Coil Splitting/Tapping.

Thanks again to Pete for the permission to post this here!

January 2013

Howdy!

In this Tech Tips newsletter I would like to discuss the wiring options possible with a single humbucking pickup which has a four conductor output cable with an independent ground lead.

The following information applies not only to conventional humbucking pickups with side by side coils, but also to stacked humbuckers and humbuckers in other size formats or configurations.

In this newsletter I do not plan to cover the details of wiring one or more switches to accomplish the possible coil configurations described below. A great deal of useful information on this topic is provided on the Stewart MacDonald website, the Guitar Nuts website and on www.deaf-eddie.net

First, let’s start with the basics:

a humbucking pickup typically has two coils in which the effective winding direction in the two coils is opposite from each other; one coil is clockwise and the other counter-clockwise. For the purposes of this discussion I will only consider a balanced humbucking pickup in which both coils are wound with the same number of turns of coil wire and both coils are wound with the same gauge wire. The magnetic polarity of these two coils will be opposite from each other (one coil will have magnetic polarity which is north up and the other south up). It is helpful to remember that the signals generated by guitar pickups are alternating current (AC) waveforms, not direct current (DC). This is important because there are two and only two phase relationships possible for the signals coming from the two coils of a humbucking pickup:

In phase (zero or 360 degree phase shift)

Out of phase (180 degree phase shift).

When the two AC signals are in phase the voltage amplitudes add [ via constructive interference] to create a strong signal; when the two AC signals are 180 degrees out of phase the two signals cancel each other [through destructive interference] resulting in a relatively weak output signal.

The topic of phase relationship of two AC voltage signals is discussed and demonstrated on:

http://www.youtube.com/watch?v=30J5U0ThRUc

While some math is presented in this video, you can ignore it completely and just pay attention to the description of the AC signals and how these signals add when they are in phase and cancel when out of phase.
Back to our main topic: the output cable of a humbucking pickup as described above will have four leads:

Coil 1 start

Coil 1 finish

Coil 2 start

Coil 2 finish

There is no universally accepted standard for color codes used for the output leads in the pickup industry.  The color codes for many popular humbucking pickups is provided here.

Here are the output lead insulation color code assignments I use:

Coil 1 start: black insulation

Coil 1 finish: white insulation

Coil 2 start: green insulation

Coil 2 finish: red insulation

There are six configuration possibilities for these two coils; let’s start with the most simple. In all of the examples below it will be assumed that the independent ground connection (often also serving as the output cable shield) is soldered to a known electrical ground such as the casing of a pot.

A: Coil 1 in single coil mode: the lead with black insulation (coil 1 start) would be connected to ground and the lead with white insulation (coil 1 finish) would be used as the hot output. The red and green leads are not used. This configuration will deliver a single coil like tone. If the humbucking pickup has balanced coil windings (the same number of turns on both coils and the same wire gauge used for both coils) the DC resistance (DCR) will be approximately half of what one would expect in series (humbucking) configuration and the output of this configuration will be approximately half of that which one would expect in series humbucking mode described in C below. The noise cancelation properties of a humbucking pickup in configuration C will be lost in this single coil mode. One could connect white to ground and use black as the hot output; this would reverse the phase of the output signal in configuration A by 180 degrees, but the tone and the strength of the signal from this one coil would be essentially the same as when black is connected to ground and white is used as the hot output.
B: Coil 2 in single coil mode: the lead with green insulation would be connected to ground and the lead with red insulation would be used as the hot output. The white and black leads are not used in this mode. This configuration will deliver a single coil like tone as described in A but with coil 2 functional. Recall that coil 1 and coil 2 have opposite magnetic orientations. If the humbucking pickup with only one coil operational is intended to be paired with a single coil pickup one might choose which coil of the humbucker is to remain functional so that the operational coil of the humbucker would have opposite magnetic polarity with respect to the single coil pickup to achieve noise cancelation.

C: Coil 1 and coil 2 in series and in phase: This is the usual humbucking configuration. The lead with black insulation would be connected to ground, the white and green leads would be connected to each other (this connection would be electrically insulated) and the lead with red insulation would be used as the hot output. The DCR of a humbucking pickup in this configuration will be approximately twice that of the DCR for configurations A and B assuming the coils of the humbucking pickup are balanced. The signals generated by vibration of the instrument strings above coil 1 and coil 2 will be in phase with each other and will add together. The output signal of a pickup in configuration C tends to be strong with a full rich tone; noise signals created in coil 1 tend to be canceled in coil 2. If the connection of the white and green leads at the free end of the output cable is shunted to ground the humbucking pickup will be coil split and coil 2 will remain operational as described in B. It is possible to wire the humbucking pickup with the two coils in series and in phase and have coil 1 remain operational when the humbucking pickup is coil split. To do this, at the free end of the output cable connect the green lead to ground, solder the red lead to the black lead and use the white lead as the hot output. To coil split one would shunt the connection of the red and black leads to ground leaving coil 1 operational.

D: Coil 1 and coil 2 in series and out of phase: The lead with black insulation would be connected to ground, the white and red leads would be connected to each other (this connection would be electrically insulated) and the lead with white insulation would be used as the hot output. The DCR of a humbucking pickup in this configuration will be approximately twice that of the DCR for configurations A and B assuming the coils of the humbucking pickup are balanced. The signals generated by vibration of the instrument strings above coil 1 and coil 2 will be out of phase with each other. The output signal of a pickup in configuration D tends to be weak with a somewhat thin tone; noise signals created in one coil will not be canceled in the other. If the connection of the white and red leads at the free end of the output cable is shunted to ground the humbucking pickup will be coil split and coil 2 will remain operational as described in B.

E: Coil 1 and coil 2 in parallel and in phase: The black and green leads would both be connected to ground, the white and red leads would be connected to each other and used as the hot output. The DCR of a humbucking pickup in this configuration will be approximately one fourth that of the DCR for configuration C (normal series humbucking) assuming the coils of the humbucking pickup are balanced. The signals generated by vibration of the instrument strings above coil 1 and coil 2 will be in phase with each other. The output signal of a pickup in configuration E tends to be moderately high output with a clear tone; noise signals created in one coil tend to be canceled in the other. Many instruments which have two reverse wound reverse polarity single coil pickups and a three position pickup selector switch (such as tele style guitars) connect the two single coils in parallel and in phase in the middle switch position.

F: Coil 1 and coil 2 in parallel and out phase: The black and red leads would both be connected to ground, the white and green leads would be connected to each other and used as the hot output. The DCR of a humbucking pickup in this configuration will be approximately one fourth that of the DCR for configuration C (normal series humbucking) assuming the coils of the humbucking pickup are balanced. The signals generated by vibration of the instrument strings above coil 1 and coil 2 will be out of phase with each other. The output signal of a pickup in configuration F tends to be weak with a somewhat thin tone; noise signals created in one coil will not be canceled in the other.

All of the configurations described above are also possible in instruments which have two single coil pickups which are reverse wound reverse polarity (RWRP).

I hope you find this information useful.

Best wishes,

Pete Biltoft

Vintage Vibe Guitars

website: www.vintagevibeguitars.com

email: info@vintagevibeguitars.com