Wiring DIY - Part 08

Modular approach to your wiring design

The best way to start designing your wiring project is to take a modular approach. Please, consider the following:

1. Resolve everything related to a single pickup (coils out-of-phase, pickup out-of-phase, coil split, coils in parallel, etc) first.
2. Resolve everything related to two pickups later.

From every "module" our goal is to get maximum two wires, the positive (the signal, the one that will be routed to the hot path) and the negative (the one that will be grounded as soon as possible).

If there is no need for using the negative wire in a further module, we will ground that negative wire whitin the module and, then, just the positive wire will exit that module.

Look at this random design approach:

The four conductors of the Neck pickup go to a Series/Parallel module, where we choose between to put both coils in series (standard humbucking) or in parallel. At the exit of this module we need to extend the negative wire, because we will allow to change the phase to whichever coils arrangement we choose on previous module. The negative wire can be then grounded on the OOP module, since there will be not needed anymore. The signal (coils in series in phase, or coils in series out of phase, or coils in parallel in phase, or coils in parallel out-of-phase) is then routed to the Neck controls (Volume and Tone, by example) and, from there, to the pickup selector (a blade switch, a swiftcraft switch or whatever else).

The four conductors of the Bridge pickup are reduced just to a signal output on the Module Humbucker/Split. This module will choose coils in series and in-phase or split to slug coil. Since the negative wire isn't needed anymore, because there are no other modules that need it, it would be grounded whitin this module. The output of this module (the positive, the signal) will be routed to the Bridge Controls (Volume, Tone...) and, from there, to the pickup selector.


Legend

For convenience, during the rest of wiring articles, we will use the following color schema for wires:

For Humbuckers: Seymour Duncan's color schema:

1. Green: negative of humbucker and start of the screw (or outsider) coil.
2. Red: positive or hot and finish of the screw (or outsider) coil.
3. White (represented in light blue in diagrams): negative and finish of the slug (or inner) coil.
4. Black: positive of the humbucker and positive and start of the slug (or inner) coil.
5. Light Grey: the bare wire or any other plate ground wire.

For Single-coils:

1. White: positive of the coil
2. Black: negative of the coil
3. Light Grey: plate ground (if there is)
4. Red: positive tap of the coil (if tapered)

For the rest of the wiring:

1. White (represented in light blue): positive wire, hot path.
2. Black: negative wire, ground network.
3. Inverted triangle: ground spot to the ground network.

Notes:

• Even if I am missing the plate ground wire of any pickup on the schema, plate ground wires go ALWAYS to ground.
• Even if I am not representing the following wires: guitar's bridge ground, guitar's shield ground, those wires go ALWAYS to ground. Any other ground wire not represented goes ALWAYS to ground.

Limitations

As we saw, we can get a maximum of 288 unique combos with two humbucker but, for this, some special switches must be used. When describing the several modules, we will consider that the complexer switch that we can have for each one is just a DPDT on/on switch.  This is convenient because, most of people doesn't like to modify the external appearance of his/her axe and, the use of DPDT on/on switches under a common pull/push or push/push pot.
When other switch is being selected for a certain mod, I will warn about it.


Single Coil Modules

We will discuss here the modules that can affect to just one single coil pickup, even that some of them can be used in general, as well.


Volume Control

Look at this picture:

The first schema corresponds to the typical way to wire a pickup to its volume control but, in a dependent way. If you have more than one single pickup wired in the same way, whichever volume control affects the whole output of the signal (that means dependent volume controls), because every volume control is "shutting up" the jack's hot.

The second schema corresponds to the independent volume control way of wiring a pickup to its volume control. The idea here is to "shut up" the pickup, instead of the jack. In that way, what happens to just on single pickup is not affecting to the overall output. This is the recommended way when more than one pickup (having its own dedicated volume control) can be selected at same time with others.

All the grounds should be linked together to create a grounding network and, it's very important that there is no ground-loop, since ground-loops are a source of noise. The best way to link all those grounding spots is in a single spot, that can be the backside of a pot's case, some screw on the shielded guitar cavity or, some improvised metallic ring where all the ground wires will finally land. It's up to you but, this is basic!.
Other side note about all this. If your electronic devices (switches, pots, etc) are all mounted over a foil or a conductive surface part of the shield, you don't need to throw any grounding wire to connect two different devices (that is, a wire from the back side of the switch to the back side of pot A, and from pot A to pot B, etc). If they all are laying over a conductive surface, their cases are already in contact so, you just need to solder your grounding wire to the backside of its case, to put every ground into contact.
Even that they aren't being represented in the picture above, your bridge-ground wire and your shield-ground wire (if your guitar is shielded) should go to the same central grounding spot as the rest of ground wires.
All these remarks related to ground are common to every module that we can see later so, I will not repeat this anymore!.

Finally, this picture are representing two ways of wiring a pickup to a volume pot for a right-handed guitarist!. If you are a left-handed guitarist, be sure to swap the two external lugs of the volume pot in this diagram!.

This diagrams apply to humbuckers and any other kind of pickup also, once you selected which coils will be in the hot path, they can be considered as single-coil pickups.


Volume and Tone Controls

There are three electrically equivalent ways to solder a cap to a pot to create a tone control. Look at this picture:

This creates some confusion but, in fact, the three ways are electrically equivalent.
We often see the second one on Gibson's LPs, by example, while the first and the third are more common on Fender's guitars. I can use any of those ways in my schemes at my convenience.

The important thing is to understand that a certain range of the high frequencies present on the signal wire (the light blue line) will be captured by the cap (orange) and then, throw to ground as soon as the tone pot is being rolled on.

Note that the negative lug of the cap is soldered to the case of the pot and, that case is being grounded (and, therefore, the cap). In guitar wiring, we don't use electrolytic caps so, any lug can be used for ground or hot but, many people prefers to ground the lug that is connected to the external plate or foil of the cap. We are always trying to leave the signal enclosed in a Faraday's cage!.

Once again, this schemes correspond to a right-handed guitar. If you are left-handed, please, swap the two extreme lugs in these diagrams.

Let use any of those three ways of wiring a cap to a pot and, let see the different ways to connect the tone pot to the volume pot. Take a look to this picture:

There are 4 ways to arrange volume and tone controls and, each one serves for a certain purpose.
As we seen, if the output signal is wired to the wiper (central lug), we have dependent volume mod and, if the output signal is wired to an extreme lug, we have independent volume mod.
If the tone input is wired to the volume's input, we have modern tone mod.
If the tone input is wired to the volume's output, we have '50s tone mod.

So, the first picture above corresponds to a dependent volume with a modern tone mod wiring. This is the most common way of wiring guitars that have global volume and tone controls. The drawback is that the sound goes very dark as soon as the volume control starts to being rolled off. That's the reason why a lot of people is trying to preserve part of its high-end content when rolling off the volume, with the help of a treble-bleed mod. This is the way as modern LPs were wiring, as well.

Second picture corresponds to a dependent volume with a '50s tone mod wiring. Tones were wired in this way on the earlier guitars but, changed to modern tone wiring later. This way of wiring the tone is smoother darkening the signal when the volume is being rolled off and, ads a bit of high-end to the signal when the volume and tone are both full on. The '50s tone mod is a good thing to test first before going for a treble-bleed mod. Is quite easy, requires no additional electronics (no more caps and resistors) and, it can be just what the doctor recommended to you. Try it!.

Third picture corresponds to an independent volume with modern tone mod wiring. This can be a way to make independent your volume controls in a LP-like guitar. By default, when you roll off one of the volumes, you are affecting the whole signal and, when one of the volumes go completely off, the guitar shuts up. With independent volumes, you can remove one of the pickups and the other will still sound, without issues. Since we have a modern tone wiring, no additional bright will be added so, if you liked the guitar sounded a tad darker, everything is OK.

Forth picture corresponds to an independent volume with '50s tone mod wiring. This is how the earlier Gibson's LPs where really wired. This gives total Independence to each pickup volume and, gives a bit of bright to the sound that helps pickups to shine a bit more over the dark wood tone. The '50s mod helps to maintain in a naturaller way the high end when the volume is being rolled off.

Once again: these diagrams correspond to right-handed guitars. If you are a left-handed, please, swap the two external lugs in EVERY pot (volume and tone)!.


Treble Bleed Mods

If you are looking for a Treble Bleed mod, first be sure to test the '50s tone mod, because it's a very natural way to loose trebles when the volume goes down but, if didn't worked for you then, it's time to test a Treble Bleed Mod. Look at this picture:

The upper one is the simplest treble mod that you can do in a guitar. It was often used in old Telecasters, to retain the snappy tone when rolling off the volume pot. To determine the right value for that cap has not direct rule, since it depends on the characteristic of your guitar's cable, the exact resistance of your volume pot and your pickup. Usually, values to work are between 620 pF and 2000 pF. Your ears will say which is the better value for your case. The drawback is that the guitar can sound unnaturally bright when turning down the volume.

Below, at left, we have the Kinman's Treble Bleed. This one uses a resistor in series with the cap, to reduce the amount of treble to be bleed out. The value of that resistor (and cap) must be determined also by every one but, usually, resistor values between the 50% to 100% of the pot resistance do the trick.

Below, at right, we have the Duncan's Treble Bleed. In this case, the resistor is in parallel with the cap, instead that in series, like in the Kinman's one. This changes the taper of the volume pot to better match the amount of treble bleed.

For single-coil pickups, the common values are a 1200 pF cap in series with a 130 KOhm resistor (for the Kinman's) and a 2000 pF cap in parallel with a 100 KOhm resistor (for the Duncan's).
For humbuckers, usually just a cap of 1000 pF does the job. I prefer Kinman's, because I don't like to change the taper of volume pot. Or 820 pF for the Bridge pickup and 1000 pF for the Neck pickup.

Note that any of those mods are linking the signal input and output lugs so, it works the same if we are wiring the pot as independent or dependent volume way. Note also that those mods are made on each volume pot that needs it but, it doesn't substitutes a Tone pot so, it's just an addition to what we were discussing previously.

Just search for treble bleed mod discussions and read the comments for every setup, to see which one can better suit your needs.


Full / Tap pickup selection

For those pickups with a taper, we can use a switch to select the full length of the wound wire or just up to the tapered spot.

Look at this picture:

The first schema is the most common way to select between the hotter and the weaker sounds of a tapered pickup. This is the way when the taper is closer (in number of wound turns) to the full finish wire.

The second one is the way if the taper is closer in wound turns to the start of the pickup.

For the third, we need an special switch, a DPDT on/on/on and therefore, it can change the aspect of your guitar. This kind of wiring makes sense only in the case that we can have turns enough of wiring between the negative wire and the tap and, between the tap and the positive wire as if they were two virtual pickups. By example, imagine that we wound from start to taper for a vintage-like single coil and, from taper to finish we wound for a Texas-hot single coil. If we choose from start to taper, we have a vintage pickup; if we choose from taper to finish we have a Texas-hot pickup; and if we choose from start to finish, we have a high-output modern pickup. Crazy, isn't it?.


Phaser switch

This can be used to change the phase of a pickup (single coil or humbucker), or to change the phase of a single coil (split humbucker, by example). If it is done inside a humbucker, it puts its coils out of phase.
If it is done at pickup level, it will put both pickups out of phase when both are being selected together.

What this DPDT on/on switch does is to reverse positive and negative wires. In-phase would mean that the input positive is being linked to the output positive and, the input negative to the output negative.
When the output negative isn't needed for a further module, you must directly ground it.
If you have one more module after (by example a serializer) you will need or not that negative output (depending on which pickup is being grounded by default in the serializer).

The phaser switch has no effect applied to just a pickup or coil. The effect takes place when the pickup is being combined with other pickup or the coil with other coil.

See that, in the picture, I am drawing a single-coil pickup with a bare (plate ground) wire. It's important that you do OOP operations with pickups that have the negative (start wire) from the plate ground wire, otherwise, you are positivizing something that was designed to control the noise.
This mod can, for sure, work even in two conductors single-coil pickups but, be aware that the risk of catching more noise is there!.

In other hand, not so much people loves the OOP sound, since the sound becomes nasal, hollow, thin and harsh. Anyway, I love more the OOP sound under high distortion, when you need a razor-like distortion that cuts everything with edgy trebles. It usually works better to put OP the Neck pickup, instead of the Bridge pickup, it's a bit smoother.

Be aware that, even that we named to this operation "to put out-of-phase or in-phase" a coil or pickup, we aren't affecting the phase of the signal in any single sense. We are just changing the electrical polarity of such a coil or pickup!.

Ok. On next part, we are going to describe modules that involve two coils or pickups.