We're back at it. Last month we gave you the first brushstrokes on the basic principles of pickup installation.
As I told you, we left a few pending issues for later, specifically details about the different wiring configurations that can be achieved with the various types of pickups.
Basically, the article I present below is a menu from which you can choose whatever magnetic pickup dish you like, with the idea that, by the end, you'll feel capable of cooking up the most varied configurations in your own kitchen; within the safety margins mentioned in May, of course. Bon appétit!
DIVING INTO THE SUBJECT: TYPES OF PICKUPS
This is a topic I've talked about on other occasions in my ISP spaces, but it's worth recalling certain details and introducing some new ones, because they are decisive when it comes to deciding what we want and how we intend to get it. Since this is an article about installing pickups, we'll focus on them in purely electronic terms, that is, without details about which pickup best suits this or that musical style. For that, you can look at previous issues of ISP, such as the one published by Mr. Raúl Rodríguez, an ISP contributing luthier (http://www.ispmusica.com/articulo.asp?id=778), or the one I wrote myself (http://www.ispmusica.com/articulo.asp?id=775) - both in the October 2006 issue - among many others.
Right, let's get to the point. Which, in our case, is electric guitar electromagnetic pickups; we'll distinguish the two fundamental types: single coils, made up of a single conductive coil; and humbuckers, made up of two.
To begin with, here are some important points regarding single-coil pickups:
First, they always have two conductors (except for the case I'll discuss later). This means that only series connections can be made.
However, in the case of humbuckers, there are two possibilities: they may have two conductors, or more than two. The case we looked at last month with the Gibson SG corresponds to two conductors (hot output and shield), with a single cable, which means the only possible wiring configuration is in series, that is, always with both coils active (humbucker mode).
So, for practical purposes, installing a two-conductor humbucker is just as complex as installing a single coil.
However, the case that gives us the most to play with is the four-conductor-plus-shield humbucker, since we can make alternative connections, such as parallel or out of phase, so we can get the sound of one of the two coils, or of both.
All of this, which applies to the world of passive pickups, applies equally to active pickups, except that these are powered by a voltage source, usually a battery with a voltage between 9 and 18 V. However, we'll go into details later about this peculiarity of active circuitry.
Something to stress before anything else is that you should check the output of the pickups you're going to install. Keep in mind that the harmonic vibration of the strings at the end of the neck is greater than at the bridge and that, therefore, the bridge pickup should have a higher output than the neck and middle pickups, if there are any.
I suspect you're eager, soldering iron in hand, to discover how to do different wiring jobs; but be patient, because a job well done depends on it.
But first of all, what guitar are we going to do the job on? Here are a few steps to follow before diving into the pool:
A) HOW MANY PICKUPS, AND IN WHAT POSITIONS?
"Well, I've changed lots of Gibson pickups, how hard can it be to change the ones on a Strat?" To start with, the pickup selector varies depending on the guitar; in the case of the typical Gibson toggle switch it has three positions and, as we saw last month, in principle corresponds to bridge pickup / both pickups / neck pickup.
But when we face the Strat case, we find five positions. What am I getting at? That you should be aware of the pin layout of your guitar's pickup selector before you start soldering like crazy, because some allow more possibilities than the ones you get by default when you buy the guitar.
Bear in mind that although our guitar may be, for example, one whose electronic design is inspired by the Les Paul style (its two humbuckers, its three-way selector...), we may then come across guitars with two humbuckers and a selector with more than three positions. What's going on? It's a fairly widespread case with brands such as Ibanez, and a clear example that a two-humbucker guitar can be much more versatile than a mere "bridge-both-neck."
B) WHAT TYPE OF BRIDGE DOES IT HAVE?
You may find this question strange, but it's more important than it seems. It's a problem of string alignment with respect to the pickups, which mainly affects the bridge pickup and occurs with humbuckers.
In the past, on the first (Gibson) humbuckers, the first and sixth pole pieces were 48 mm apart, compared with 51 mm on Fender single coils. When Floyd Rose bridges started to become popular, it turned out there was a problem with humbuckers: the structure of these bridges meant the strings were spaced farther apart (specifically, with the measurements previously adopted by Fender), with the resulting misalignment of the strings relative to the humbucker pole pieces. This has an adverse effect on the guitar's output and sound quality, especially when picking the first and sixth strings.
What happened? The vast majority of the world's pickup manufacturers had adopted Gibson's measurements to make their humbuckers, so they were affected by this problem; they soon reacted by bringing out the same pickup models, only with "Fender-Floyd Rose spacing" on the pole pieces.
However, Floyd Rose bridges aren't the only ones with "Fender-style" measurements; other brands also use them.
Keep in mind that most single-coil pickups follow a Fender layout, while standard humbuckers are based on Gibson, so you must be very aware of what type of bridge is fitted to the guitar.
C) IDENTIFYING THE PICKUP WIRES
This varies by manufacturer. Generally, two-wire pickups have the hot output identified by the color black, and the shield usually has the natural color of the conductive metal, for example aluminum. That said, the shield, instead of being designed as one or more conductor wires running alongside the others, may be built as a braid that wraps around the rest of the wires, as we saw with the Gibson pickups removed from the SG.
And what about four-wire-plus-shield humbuckers? Two wires come from the start of each coil and another two from the end. That way, they can be connected in series, parallel, out of phase and more. If we don't want to take advantage of these features and only want humbucker sound, simply follow the diagram shown in the first chapter.
Since last month we used Seymour Duncan as our reference, in this article we'll follow that manufacturer's scheme for identifying wires by color: green = start of the adjustable coil; red = end of the adjustable coil; black = start of the fixed coil; white = end of the fixed coil. The fixed coil is understood to be oriented to magnetic north, and the polarity of the adjustable coil is magnetic south.
Figure 1 shows the wiring of some major companies. What do you think? Although we're following Duncan's criteria, if you want to install a pickup from another company, simply replace the Duncan colors throughout the article with those of the corresponding company.
PICKUP CONFIGURATION DIAGRAMS
At last we reach the most eagerly awaited section. But first, let's review. Have you taken safety precautions and are you clear on everything above? If so, read on. We'll skip the case of two humbuckers with a three-way selector, since it was described in detail last month in the first chapter.
Note: Remember that the best way to ground is by soldering onto the pots, since these connect to the bridge, and the bridge to ground.
A) Humbucker with coil split
This setup involves installing a switch, usually located on the volume or tone pot, that lets us switch between activating both coils of a humbucker or only the one oriented to magnetic north.
To do this, you'll need a 500 kOhm pot (at least, although it's the most recommended option) with a push-pull switch. The goal is that, once all the work is done, pulling up the pot activates only the north coil and pushing it down connects the coils in series. That way you can get both single-coil and humbucker sounds. Keep in mind that 500 kOhms is called for because, when you pull the switch and "silence" the south coil, the resulting impedance is 250 kOhms, that is, the normal value for a single coil.
Take a look at figure 2 and compare it with the circuit diagram for a standard humbucker installation, as we did with the SG (figure 2b).
B) Humbucker with parallel wiring
This configuration is often confused with coil split. Parallel wiring connects the coils of the humbucker as if they were two single coils working independently.
The result? A brighter sound, with a tone closer to that of a single coil, but without losing the noise-canceling feature typical of humbuckers.
A humbucker connected in parallel loses around 30% of the output that the same humbucker would have when connected in series.
Take a look at figure 3. As you can see, it's a more laborious job than the coil-split case, but switching between series and parallel can be even more attractive, depending on your preferences.
C) Out-of-phase humbucker
This consists of combining two coils (it could also be two pickups), either in parallel or in series, but with the polarity of the signals combined in such a way that part of the signal is audibly canceled. The low frequencies are filtered out and the result is a "thin" sound with a somewhat "nasal" tone.
In figure 4 you can see the pot configuration in detail, as well as the analogous case, only with split mode (figure 5).
D) One humbucker and two single coils
Now we're going to raise the bar a little. We'll start including complete pickup sets, so you can see how to proceed when soldering with different switches.
In this case, we show the typical Fat Strat configuration, with a four-conductor humbucker, two single coils and a five-way switch, whose positions are as follows: full bridge humbucker, full bridge humbucker and middle single coil, middle single coil, neck single coil and middle single coil, neck single coil.
The second position (full humbucker + middle single coil) is due to the fact that, as you can see, the humbucker has been installed in the standard way, as in figure 2b. The single coils have their black wire going to ground and their white wire to the switch.
So study figure 6. It may seem tedious, but the design is actually very simple, although that doesn't make it quick to carry out.
E) Two humbuckers and a single coil, with dual coil split
This is one of my favorite configurations. In this case, we have a five-way switch and a 500 kOhm push-pull like the one described above. Results? We can choose the five positions (full neck humbucker, neck-middle, middle, middle-bridge, full bridge humbucker). But not only these five, because with the push-pull we "transform" the humbuckers into single coils, so we can get four new sounds (single-coil neck, single-coil neck-middle, middle-single-coil bridge and single-coil bridge). If you don't want to split one of the humbuckers, just wire it in standard mode (soldering the red and white wires together, the black one to the switch, and the shield and bridge to ground).
Follow the diagram in figure 7. As you can see, it's a matter of doubling the job of installing a coil-split humbucker, installing a single coil, and soldering the corresponding wires to the switch.
F) Two humbuckers with a five-way switch.
If you're not keen on having a pickup in the middle position of the body, want to do without a push-pull, and are only interested in playing with humbuckers, then this configuration is for you. It combines the classic possibilities of two humbuckers with a three-way switch (neck-both-bridge) with two more sounds: coil split on the neck humbucker and coil split on the bridge humbucker, both activating the north (inner) coil.
In figure 8 you can see how to do this type of wiring, which is versatile, to say the least.
G) I want active pickups
This is a case that may require somewhat more precise workmanship, depending on the option we choose. Keep in mind that active pickups generally require one or two 9V batteries, which must be housed somewhere. There are several options for this. One is to check whether the control cavity has enough space to hold the battery and install it there; the other is to rout a cavity in the back of the guitar. The latter is laborious, since a channel has to be opened to connect the battery to the rest of the circuit. Leave this job to a luthier.
As for the wiring, there's no problem, since companies usually include as standard everything needed to install the pickup and make it work. Keep in mind that you'll be given a three-lug output jack, in order to connect the battery grounds, the volume lug and the casing of either of the two pots (remember that we used them for grounding).
Figure 9 shows the generic installation diagram for an active humbucker, with two pots (100 kOhms each). One of the conductors connects to the voltage source (a 9V battery in this case); the white one acts as the hot output and will therefore be connected to the pickup selector.
In many of these configurations you've seen that, in some cases, getting a push-pull switch is essential. However, if that's inconvenient, you can always drill a hole in the guitar and install a mini switch for the same purposes.
One more thing worth pointing out: if you have a Strat with three single coils and would also like to get something close to a Telecaster sound in the middle position of the switch, you might like the idea of putting the neck and bridge single coils in series, deactivating the middle one. Try it!
CONFIGURATIONS OF SOME GUITAR LEGENDS
It's true that, knowing the subject, we can figure out what's best for our guitar so that it sounds the way we want. But what if we snoop around a bit in the insides of a few renowned guitarists' instruments? If we love their sounds, it will surely be easier to reproduce them ourselves on our own instruments.
A) JIMMY PAGE
There's no style Jimmy hasn't played. In figure 10 you can feast your eyes on the secrets his Les Paul hid inside.
It's a good example: a diagram that provides a wide variety of sounds from two humbuckers, and that shows you the possibility of putting one pickup out of phase with the other (not just two coils of the same humbucker). In this case, the possibilities are, in addition to the three basic sounds (neck-both-bridge) we get with the switch, those obtained with no fewer than four 500 kOhm push-pull switches, built into the four pots respectively: bridge pickup volume (bridge pickup split), neck pickup volume (neck pickup split), bridge pickup tone (puts one pickup out of phase with the other) and neck pickup tone (connects both pickups in series). A real machine.
B) GEORGE LYNCH
Another rocker of undisputed talent. A much simpler setup, with a single coil in the neck and a humbucker in the bridge. If you look closely, his Kamikaze doesn't have a separate pickup selector; instead it's built into the push-pull on the volume pot. If we pull it up, we activate the neck pickup; if we push it down, we activate the bridge pickup. On to figure 11.
C) BRIAN MAY
Red Special. And I turned just as red when I first analyzed this axe. Another guitar famous for its multiple wiring possibilities. He connected his pickups in series and fitted six switches in the body to reverse the phase. That way he alternated the north-south orientation, getting more sounds, in terms of wiring configuration, than most well-known guitars of the time.
Figure 12 shows the diagram of this rock monster's guitar.
CONCLUSION
First of all, I must express my deep regret at not having been able to go on longer or give more detail on what's been covered, since the space limit didn't allow it. However, we'll come back to the topic in the future.
Pickup configuration, as you can see, is not very complicated in theory. The most important thing, in my opinion, is that you're very clear about what results you expect from what you intend to do when installing pickups. It's a rich, vast and fascinating world, to the point that, as you know, there are professionals and large companies devoted solely and exclusively to making and overseeing pickups.
And after these two episodes, I'll repeat the question: unhappy? The answer is in your hands and your soldering iron.