Pickups
The basic principle of a standard pickup is that there is a magnet that picks up the metal strings vibration and the signal is amplified by copper wire that is wrapped around the coil. The wire has two ends on it, the beginning and the end or an in (Hot) and an out (Ground)

The size of the copper wire and the amount of turns on the coil control the output volume and tone of the pickup. The basic principle in pickup design is as follows the less winds of wire on a coil will cause the pickup to have less output and more treble or highs. The more winds on a coil will cause the output to be louder and more lows or bass response. The same holds true with the wire gauge, the thinner the wire the more treble will be produced the thicker the wire the more bass response. Too many winds will cause the pickup to distort so the designer needs to be very careful.

There are also high impedance and low impedance pickups, the difference is that to get the most output many people would put as many turns on the coil as possible. This of course would distort and also cause the pickup to become noisy, Not only does the wire pickup the strings but it also pickups noise. This is why Low impedance pickups were invented. The idea of Low impedance pickups is that basically they use less turns on the coils and then the output of the coil is modified by a small pre-amp inside the pickup, this balances the output and removes any noise.

Low impedance pickups are used today mostly on basses because bass players like more tone control, less distortion and no noise on the bass. Many times the low impedance pickups are also used with an EQ system that can boost the treble and bass usually by +-15DB. For guitar players Low impedance pickups can seem unnatural to there ears so although about ten years ago these were very popular, today most people are staying away from these.Å

High impedance pickups have also come along way since back in the 1980's. Manufactures understand how important it is to make good quality quiet pickups. To start with they need good materials like the wire, magnets and all the metal parts. If a pickup is made and the wires are not wrapped tight or if there is any part that is loose and vibrates this will cause the pickup to squeal or feedback at higher volumes. This make the guitar almost impossible to play loud. Pickup manufactures seal the wire and coils in wax after they wind them, this fills and space that is between the wire and stops the feedback.

 

Magnets
Basically there are two types of magnets used in pickup construction , they are ceramic or alnico, alnico is aluminum, nickel and cobalt. Each of these magnets have there own properties and reasons that they are used. (Note there are also rare earth magnets that are starting to appear)

My feeling on this matter is as follows but some people may disagree.

Alnico is softer than ceramic and it causes the notes to have a slower attack and a longer sustain. Alnico was basically used for the magnetized pole pieces on single coil pickups. It is also used sometimes as a regular bar magnet on humbucking pickups. From my experience alnico is a softer sounding material.

Ceramic magnets are very hard with a quick sharp attack. What I use to describe the difference between alnico and ceramic is that if you drop both magnets from about 3 meters the ceramic magnets will shatter into pieces while the alnico will make a thud on the ground and maybe get dented. If you think about this then you will understand the difference in sound of the two materials.

 Pickup Winding Machine
 

Wire gauge and amount of turns.

Each pickup has its own "recipe", there are many types of wire gauges and amount of turns on coils that make them louder, deeper or hotter. Basically less winds causes a pickup to have less output and more high end while more winds causes more output and deeper sounds.

Most humbucking pickups use the same amount of turns on each coil of the pickup. However some companies have a combination of two differently wound coils they call Woofer / Tweeter pickups. These use two different winds on each bobbin in the humbucker and causes a different effect on the sound and different characters of the pickup. Generally if the two coils are not exactly the same the pickup will be noisier then two identical coils. For example a humbucking pickup with two coils that are 5000 turns on each bobbin will be quiet, but a pickup that has two coils and one is 5000 and the other is 4000 will be noisier.

   

Wiring
Pickup wiring is not so difficult but you do need to understand a few things that can make or break the wiring. Basically here they are.

Series Wiring
Most humbuckers are wired in series. Series means that the there are at least two coils and the pickup is wired with one hot and one ground and the two pickups are connected straight through. This gives the maximum output.

Parallel Wiring
If we take the same setup and wire it in parallel. Now there are still two coils but each has a hot and ground. Some Strat's in the 2 and 4 position have the pickups humbucking but they are in parallel with each other. A basic humbucker can be wired as either. This seems to produce a less output more natural sound.

Single Coil
A humbucking pickup can be used as a single coil if one of the coils is sent to ground. In this case there is only one hot and the other three wires are grounded.

Out Of Phase
This used to be allot more popular in the old days but most people don't like this sound now a days. This is when you change the pickups wiring so that the in and out wires are reversed on one of the pickups, this cause's a effect called out of phase where the actual coils are out of phase with each other.

What pickup is best for you?
This is an impossible question that people always ask me. It always depends on what you are looking for and also what you are playing through. First we need to figure out what you are using and what you want to decide what pickups will work for you.

Here are some examples of pickups that I have suggested to people and why. This is not a guide to what pickups are the best that is personal preferences but I hope this can give you some idea of what kind of options there are.

When someone comes to me and asks me what pickups they should use I first ask what they play through. For example the main setup is basically a tube head. The controls are Master Volume, Gain, Presence, Treb, Mid and Bass, a slant 4-12 cabinet with celestion 70's in it. For settings the Bass on 10, The Treble on 4 and the Mid on about 4. The presence setting depends on the room . It is either all the way up or all the way down.

The main guitar is a hot rodded Strat body. (alder with a maple fretboard) No processors just a guitar and amp and a wah-wah in between.

This guitar has two humbuckers and he wants a fat sound. I would suggest some hotter pickups that can drive an amp.

Another guitar that needs a more mellow sound is a hollow body. If I used the same setup on this as above it would sound awful. He uses a 1965 Fender Dual Showman Amp with a 2-10 cabinet. This guitar would feed back with pickups that are too hot because it is hollow. So I use two less output pickups that are mellow and don't feed back at high volumes.

A friend of mine once called me and complained that his pickups squeal. I checked his guitar through my setup (It was a Lespaul with two super distortion pickups) and it was fine. Then we looked at his rig and decided to change his pickups. Basically he was using a Digitech guitar processor and a full 100 watt Marshall Jubilee. My first thought was this must have allot of gain and too much high end. The processor takes the signal and modifies it before the amp gets it. I suggested he change his pickups to a less powerful pickup and we installed Dimarzio® PAF Pros. This fixed the problem.

The best thing I can tell you about replacement pickups is that do your research before you buy. There are many pickup companies out there and they make all different kinds of pickups. The World Wide Web on the Internet is a great place to get information from pickup makers. If you go to a search guide like Yahoo or Webcrawler and search for pickup companies you will see many. Of course each company states that they are the best at what they do so use your best judgment and investigate each company and the pickups that they offer before deciding on what pickups will work for you.

Since the beginning of pickup replacement companies such as Dimarzio® or Duncan try to name the pickups to match what they were designed for. The purpose of this is course so that the name gives you a feeling of what the pickup will sound like. For example one of the first replacement pickups from Dimarzio® was the Super Distortion pickup, by the name you know exactly what you are getting. Other ones are like Duncan® Quaterpounder, this also tells that it is powerful. Some other names of pickups that are easy to tell what they were designed for are the Tone Zone, Humbucker from Hell, Screaming Demon, HS1-HS2 (Humbucking Stack) '59, Antiquity, Hot Rails, Pearly Gates, Dual Sound, Fast Track 2 and X2N. Can you guess why the Joe Satriani uses a Fred pickup? Here is the true story way back in the late 1980's, Dimarzio® started working with Joe to make some new pickups for him. Steve Blucher at Dimarzio® made many samples and finally it came down to four pickups that they sent to Joe. Steve needed to call each one something so that Joe could tell him the one he liked so he named them after the cartoon Characters on the Flintstones. We received four pickup's the Dino,Wilma, Fred and Barney. Luckily Joe liked the Fred pickup or everyone would be using a Barney, a Wilma or a Dino.

Guitar pickups also are available is two different styles, one being a single coil like a Stratocaster® uses and the other is a Humbucking pickup that has two coils. The purpose of the humbucker is so the pickup is to be quiet with more output. Single coil pickups only have one polarity north or south so they have what we call 60 cycle Hum. If you take two coils and put them next to each other and have one coil north polarity and the other coil south polarity then the pickup will humbuck and be quiet. Basically each coil cancels the other one out.

The reason people still use single coil pickups is because they have a certain sound that a humbucker can't get. They are noisy but the tone they produce has more treble response than a humbucker. Another reason is most single coils have the pole pieces magnetized so the notes response to the pickup from the string is instant or we say has a very sharp and quick attack. This is the Fender sound.

Other types of pickups that are used on guitars and especially acoustics are Piezo electric pickups, These can either be under the bridge or actually part of the saddle. These work by picking up the string pressure on the saddle and then the sound is amplified. These tend to sound more bright like an acoustic sound because they are actually picking up the sound at the saddle location. This type of system can be used to make an electric solid body guitar sound like an acoustic. Many companies make these systems these days the best being either Fishman®, Shadow or Mike Christian. Mike Christian makes replacement saddles for most bridges and they can easily be installed. This is great for the electric player that only needs to do a few acoustic songs but does not want to bring an extra acoustic to every gig.

When using a Piezo pickup saddle along with regular guitar pickups it is recommend that you have two output jacks one for the standard pickups and another for the Piezo system. The reason behind this is mainly that the standard pickups will produce an electric guitar tone through an amp and the Piezo pickups through the same amp will overdrive and sound more like an electric guitar. Most people plug the Piezo pickup system into either the PA direct or into a different amp that is set more to a true electric acoustic sound.

When looking at a guitar and seeing the pickups placement on the body there are reasons for this. Basically the closer to the neck the pickup is the deeper tones will be produced, the closer to the bridge the pickup is located the more treble sound is produced. This is the reason a Lespaul® can be marked as the neck pickup for rhythm or more bass and the bridge pickup for treble or more highs.

The pickups are usually located under a strings harmonic. This is done to get the most character from the pickup. A strings harmonic is basically a location on the string that has overtones or can produce another note other then the open string. The best way to find this points is to just touch you finger on the top of the string in various locations over the frets or pickups. When you pick the string you will here other notes. The loudest and easiest harmonics to play are at the fifth, seventh and twelfth frets.

The placement of the pickup also has allot to do with certain sounds that are produced, For an example a Stratocaster® has three pickups the bridge pickup is angled for more even output. The pole pieces on the pickup are staggered for different strings. Leo Fender designed the Strat to have a wound G string so many people can find that when they use a standard plain steel string the note is pulled sharp from the magnetic pull of the pole piece. This is what we call "stratitis". Basically when ever you play the G string the note sounds sharp. It is easy to see on a tuner because the G note will have a hard time stopping the needle. The remedy for this is easy, lower the pickups or raise the G string at the saddle.

The placement of the neck pickup is located for a nice warm sound that is great to play rhythm with and also to play nice slow low end leads. The sound in this position is very smooth without too much treble.

When the switch is in the second position and the neck and middle pickups are on together the pickups can actually be humbucking, if the center pickup has a reversed polarity on the magnet. This is different from a standard humbucker in two ways first the location of the pickups is wider then a standard humbucker and second because each pickup is wired to the switch, so there are two hot and two grounds this is what we call wiring in parallel. Parallel wiring reduces the output of the pickup or actually thins out the sound of a full humbucker. This is one of my favorite selections to play rhythm even more than the neck pickup.

The center pickup is really in a bad spot and the sound it produces is kind of plain with no real character. I don't know many people that use this position allot.

The fourth position or bridge and middle pickups on a Strat is also a great quiet twang sound with more highs then the second position because the location of the bridge pickup closer to the bridge.

Finally the bridge pickup by itself has the most harmonic response to an amp and this allows for the highs to be more produced and is basically used for playing leads or notes that you want to stand out. The meaning is that in this position the actual strings are more noticeable through an amplifier because of the treble response.

Ibanez and Dimarzio® came up with the Humbucker/Single/Humbucker Idea that Ibanez calls a Split 5 wiring this allows for the full humbucker in the bridge and neck positions but in the two and four position you get the Stratocaster® two and four sounds in parallel also. Kind of the best of both worlds a Lespaul and a Strat.

On a guitar such as a Telecaster the neck pickup has a smaller bobbin that is underwound, this along with the metal cover gives it a very thin tone that is great for rhythm playing, The bridge pickup gets its added high by being mounted into a large bridge plate, This also adds highs to it.

BASS PICKUPS

On a bass the location of the pickups is very important , on most basses that have two pickups (such as a Fender P bass) with a Precision pickup and a Jazz pickup. Precision pickups were named because it actually has two coils one located closer to the neck and the other located closer to the bridge. And the standard straight pickup or Jazz bass pickup is placed closer to the bridge for more highs. A standard Jazz bass has two J bass pickups and the neck pickup does have more bass response because of the location , but still the P pickup has more variety in tone because the location of the coils with the strings. This is because the gauges of the bass strings are much different than a guitar or the low E string is really fat while the high G string is much thinner. The split coils allows this to be compensated.

More basses now use more of a soap bar design pickup, This is a humbucking pickup under one big cover. Bartloini, EMG and many other companies are using these. Bigger does not always mean better but it does allow different bobbins and more options in the position of the bobbins under the strings. Many times a simple P pickup postion of two coils will sit under the cover. Some of these are active but many are actually passive deisgns. One easy way to figure the coils location is to take a magnet and lay it on top of the cover, It will stick or repel from wherever the magnet is. I have also (Steve Blucher will kill me for saying this) used steel wool on top of the coil to see where the magnets are. This is like how a magna doodle works.

On a MusicMann bass this uses large Alnico Slugs, sort of a super Strat pickup. Not only is this the Music mann sound but also the location of the pickup itself.

Many bass players prefer some type of active circuit, either the pickups and EQ or like a Bartolini® that has passive pickups and an active EQ. Active pickups I talked about above but active EQs are used to boost or cut frequency's usually the treble and bass frequency +/- maybe 15DB or so. More often these days added Mid frequency boost/ cuts are also available some with added sweeping of the mid frequency's.