Wiring DIY - Part 01

Introduction

 

One day you will be curious about how to get more sounds from your axe or how to change something that you don't like on how the controls are being mapped. Maybe, you think that you better don't touch your axe and, that's fine as far as you don't know how it works and how to achieve your goals but, the good thing is that this is not so difficult at all and that, even if you are doing a bad wiring, the worst thing that can happens is that you don't get any sound or some of the positions of your selector switch until you fix the issue but, in no case you will damage your amp or rest of equipment (pedals, etc).

 

Alright. The best way to start wiring is to understand which electronics components are usually found in an electric guitar, how they work and what else can be done with all them. So, this first part will be focused on components description but, mainly on pickups.

 

 

Electronic Components in an Electric Guitar

 

We will review the most common electronics components that you can find in an Electric Guitar. For sure, there will be even more not described here, since there is always something new in that world but, most of guitars will include at least one or more of the components described here.

 

 

Pickups

 

This is were the magic begins. You can think on pickups as the real source for your sound, they generate your guitar's sound and, they way as they do it is, at same time, tricky and simple. But, let see how everything started first.


A bit of history

 

First type of pickup ever used was the Contact Pickup. Contact pickups use some mechanism to feel the vibration of the guitar and transduce such a vibration to electrical signals, that will be lately amplified by a guitar amp. They give the typical acoustic sound of a guitar but, they aren't so interesting when we are talking about solid body guitars. Even that this is an interesting pickup type, that can be in use even today for acoustic guitars, we will focus on the most common electric guitar's pickup types.

 

When solid guitars started their production, the Electromagnetic Pickup was born. This is the most common type of pickup you can find in a solid-body or semi-acoustic guitar, nowadays.

 

The electromagnetic pickup creates an electromagnetic field that remains stable while strings aren't on movement. When strings are strummed, since they are metallic, they alter the electromagnetic field, that induces a current on its coil. That current is routed to the guitar's jack, to be sent to the amp for its amplification.

 

The first documented magnetic pickup was made in 1931 and used for Rickenbacker's solid aluminium guitar. The design was a bit different from what we can see nowadays. It consisted in a coil, with some pole pieces, surrounded with a magnetic bar, with the shape of a very closed "C" that maintained strings between the coil and the extremes of that "C".

 

 

 

In 1932, Dopyera Brothers included inside their Dobro Resonator guitars a pickup built with a magnet surrounded with copper wire.

 

A bit later, in 1934 or 1935, Gibson started to make electric Hawaiian guitars and banjos that incorporated some magnetic pickup but, it wasn't until the release of their Electric Spanish guitars (ES), around 1937, that pickups started to take consistence. The Gibson ES150 as the first one that won the respect of musics, loaded with Charlie Christian's pickups.

 

Paul Bigsby created the first modern solid body electric guitar, around 1947 and, his guitar included some pickup designed by himself, consisting in a bar magnet wound with copper wire.

 

Then, in 1948, Fender released their first massively produced solid body guitar in the world, the Broadcaster, that had pickups consisting in six vertical alnico magnets wound with copper wire (that is, the first single coil pickup). This guitar was renamed Telecaster, later.

 

Gibson introduced their Les Paul model in 1952 and, this guitar included a revolutionary pickup designed by Seth Lover, the pickup consisted in two twin coils surrounding their own six pole pieces and, laying both over a magnetic bar, everything enclosed in a metallic cover. The Humbucker was born and, this design was known as P.A.F. (Patent Applied For) and, it's still the reference for vintage humbucker' sound.

 

For sure there are many other designs, still in use, as mini-humbuckers, active pickups, P90 and, even pickups with more than two coils (motherbucker), etc. But, what all them share is that a pickup creates a magnetic field, that can be extended with the use of pole pieces (metallic posts, not magnetic) and that, when strings vibrate, the alterations of such a magnetic field generate an electric signal to be amplified later.

 

Pickup Classes 

 

There are two main classes: Active and Passive pickups.

 

Active pickups need of Active Electronics components to pre-amplify the signal before it exits the guitar. The signal generated within an active pickup is very low so, an active pickup will need some special pre-amplification circuit to raise the level of the signal to the standard level that can be achieved with passive pickups. To do this, this kind of circuits need to be powered by a battery so, every active pickup needs a battery compartment and, a loaded battery to work.

 

The signal produced by this pickups is more Hi-Fi than the rude sound generated in passive pickups and, as every time happens with electric guitar, the most Hi-Fi that the sound goes, the less interesting to the musical ear is. The pros of this type of pickups is that they work awesome to get every note with pristine clarity and, with a very low floor noise and, there are often used for shredding under very high gain environments.

 

The drawback is that you can run out of battery at any moment and, if this happens, your guitar will suddenly shut up, until you replace the battery.

 

Passive pickups are generating a higher signal so, they doesn't need pre-amplification circuits, the signal can be directly amplified by the amp itself. The sound of a passive pickup is more rude, includes more floor noise (and very specially, single coils) and sounds more undefined. The pro is that the sound of a passive pickup is always more musical to the ear, warmer and more natural. The con is that they introduce significatively more floor noise and, if the pickup is "unpotted", it can be prone to microphonics issues.

 

Within every of those both classes, pickups can be classified by several aspects:

 

• Number of coils
• Type of poles (posts, bars, vertical bars, etc).
• Type of magnets (alnico II, alnico III, alnico IV, alnico V, alnico VIII)
• Output (low, medium, high)
• Vibe (vintage, hot, high gain)
• etc.

 

Single Coil Pickups

 

This was the first modern pickup, in the way that we know them nowadays.

 

The idea is quite simple. A magnetic bar was cut in six little bars (one by string) to create the magnetic field. Those bars (poles) were fixed at bottom and top with two pieces that supported them standing up (vertical). Then, an isolated wire of copper was wrapping those poles, with around 7000 turns. The coil was protected with a plastic cover and, the start and finish of the wrapped wire where soldered to a pair of conductors to route the signal out of the pickup.

 

This is the typical pickup that Fender's guitars loaded from the very beginning and, responsible for the tones of Telecaster and Stratocaster guitars, by example. They can be a bit noisy and, are prone to feedback issues. If they aren't wax potted, the feedback will make their wire to friction with itself and this will lead to microphonics issues.

 

They usually have a high attack, are bright, snappy, and bell-like sounding. With the right design (magnets, wound turns, wire type, etc), can be awesome for clean work with attitude.

 

P90, soapbar, eardog and other single coil pickups differ a bit in the design (and they are even bigger in size). They have screws as poles (not magnetized) and the magnet is just a bar that lies under those poles. The voice is slightly different to Fender's, because the shape of the magnetic field created by 6 vertical magnets is different of the magnetic field created by an horizontal magnet bar that increases the field with those screws.

 

Single coils are usually more clear sounding than humbuckers (or multi-coil pickups).

 We already mentioned their drawbacks and, that's the reason why there are some tries to minimize the noise (noiseless single coil pickup) coming from practically every well know pickups Maker.

 

• Some are using a dummy coil below the real one just to cancel the noise.
• Some are using two half coils inside, one to cover one half of pickup and other to cover the other half.
• Some are using some special magnets (as the Samarian-Cobalt in Noiseless).
• Some are using some special trick, as Shure.

 

Well, the real thing is that to kill the noise affects also to the sound and, those pickups start to sound not so appealing with those solutions but, if you are fed up of noise but you still love single coil's vibe, you can always try one of those solutions to see if they leave enough mojo for you.

 

 

Humbuckers

 

 

Since single coils were so noisy (and specially if they were unpotted), Les Paul models started to work with another approach. Seth Lover designed a way to cancel the hum inside a pickup and, since it bucked the hum, it was called humbucker.

Each coil has an opposite magnetized field and, coils are connect with inverse electrical polarity. What at the end happens is that everything that the magnetic field catches is being cancelled while everything that the pole pieces get is being accepted.

 

When humbuckers have twin coils if when they have the major hum rejection ratio. Even that the original design was like this, nowadays, a lot of humbucker models have differently voiced coils (specially if they are used for splitting tasks) and, therefore, some floor noise can pop up.

 

First humbucker designs, made by Seth Lover, had an sticker or writing on the back plate that read P.A.F. (Patent Applied For) and, you will hear this term very often to people that is trying to get that vintage vibe that the early humbuckers (PAF) had.

 

Original PAFs had their coils in series and that made their signal powerfuler than a single pickup, what added more sustain and a warmer and thicker sound. While the first PAFs have an output level very close to first single coils, nowadays they are humbuckers with an output up to three times the vintage one.

 

In pickups' world, everything matters. The height of the coils (taller = treblier), capacity of bobbins, turns of wire, wire gauge, wire's isolant type, wounding method (auto, scattered), magnet's size, magnet's material, magnet's molecular alignment (rough, casted, aligned, ...), etc. This results in very different voiced pickups and, the slightest change can make a big difference.

 

Traditionally, the pair of bobbins inside a humbucker were connected in series (imagine a train with two wagons) but, lately, they started to release humbuckers with 4 conductors, each pair corresponding to the start and finish of each of the two coils. In that way, with a tricky wiring, we can select any of the two coils or to arrange them in a different way (parallel-series, in phase-out of phase).

The ground wire is always soldered to the base plate.

 

Nowadays, you can see humbuckers with and without cover. The cover was part of the trick to make the humbucker to reject the noise. As we know, any electronic component enclosed in a metallic cage that is connected to ground (Faraday's cage) will reject most of noise. Humbuckers without cover aren't inside a Faraday's cage and therefore, are more prone to catch noise and interferences, while covered humbuckers are quieter.

 

Even splitting a humbucker (that is, selecting just one coil), you will never get the same sound as with a traditionally single coil. The coils of a humbucker lie over a magnetic bar and, therefore, the magnetic field is in principle horizontal. The trick of using pole pieces and screws inside the bobbins helps to project the magnetic field over the pickup, in the area of vibration of strings. But, since the pure single coils have magnetic pole pieces, in vertical position, the magnetic field that they create is vertical and react in a different way as a coil inside a humbucker.

The opposite is also true, if you put together two pure single coils, to create a humbucker, you will never get same sound that you achieve with a pure humbucker and, reason is exactly the same: different shape-orientation of the magnetic field, results in different induced electrical signals.

 

 

Active Pickups

 

EMG is a very well known Maker who is mainly delivering Active Pickups. For a long time, it covered practically the whole market with their models, specially EMG 81 and EMG 85.

But, while those kind of pickups, with a very similar look to a passive pickup (except for the absence of visible pole pieces or screws) is what we usually know as an Active Pickup, any pickup that needs active electronic components is an active pickup.

 

As we said, this kind of pickups need a pre-amp circuit able to raise their low signal level up to the level that traditional passive pickups deliver. So, they way as those pickups are wired inside a guitar is different and, it includes the use of one or more batteries and one or more PCB (Printed Card Boards) with one or more circuits (pre-amp, middles booster, etc.).

 

While with passive pickups we use switches to select wires and get the results we are looking for, in active pickups some changes can be made just if we add some more PCB circuit or any other active device.

We already discussed pros and cons of using such a kind of pickups.

 

 

Piezo Pickups

 

Piezo criytals are able to generate electrical signals when suffering pressure differences and, that's the principle behind Piezo pickups. Those pickups need to be in touch with a vibrating area that creates slight pressure differences that generate very low electrical signals. Due to the low signal level, those pickups need active electronics to pre amplify the signal up to the typical levels of passive pickups.

 

Even that those pickups were mainly used in acoustic guitars, it's not so strange to see them in an electrical guitar, specially in semi-acoustic guitars.

 

The most usual is to see those pickups delivered under the saddles of a guitar's bridge so, they can directly catch the vibration from the strings (Ghost piezo saddles, by example) but, they can also consist in some kind of bar that sets horizontally under the bridge or under the fretboard (Epiphone Ultra II).

The signal of each saddle is the mixed together and sent to a pre-amplification stage, before it can exit the guitar.

 

You cannot directly mix a piezo or active pickup signal with a passive pickup signal, you need first to pre amplify any active signal before you can mix both types. The preamplifier includes also the proper filters to get exactly the kind of targeted sound.

 

Piezo pickups deliver an acoustic-like tone, very different from the typical electrical-like tone that is being achieved with typical passive and active pickups. Guitars with piezo pickups usually have a blend control that allows to mix the electrical and acoustic sound to get a wide range of nuances in the sound. Also, it is very common to have or different outputs (electric and acoustic) or an stereo output (electrical and acoustic in separate stereo channels) to allow to run every signal in a different amp, by example.

 

 

Other pickups

 

There are variate designs currently available, as the 4-coils Motherbucker, and some hybrids that try to get the sound of a P90 when split and the sound of a humbucker when full (P-Rails), or a strato-like single coil when split and a single-sized humbucker when full, etc.

But, the thing that will determine which possibilities of wiring a pickup has is if it is Active or Passive, because rest of components in the circuit should be used accordingly to this.

There is always a way to mix both worlds, after the active signal has been preamplified. 

 

Some pickups are humbuckers (two coils) that will be a direct replacement for a strato single-coil pickup, those are being called single-sized humbuckers. Each coil can cover half of the pickup or, they can be stacked (vertically).