Archive for the ‘Losie’ Category

Riding The Knobs – Pots in Perspective

Tuesday, March 20th, 2007

Have you ever watched the concert videos of some classic rock band? I still remember the first time that I saw Led Zeppelin’s “The Song Remains The Same”. Wow, Jimmy Page really was the embodiment of a guitar God, wasn’t he? When I started playing electric guitar, I was in awe at how he could dial in any number of tones just by turning the knobs on his Les Paul. No sir, he wasn’t touching his amps or pedals every twenty seconds, just his guitar. It took a fair bit of playing before I learned to use the knobs on my guitars, but eventually I was able to go from a shimmering clean sound to an aggressive distortion just by turning the volume knob and playing harder. So how do these magic “knobs” work?

First of all, the knob is only the decorative and tactile cap on top of the device that does the real work. Underneath is something called a potentiometer, pot for short. Potentiometers are electrical components that behave much like a variable resistor. On the outside, they have a spinning shaft and three terminals. Within their casing, they have a ring of a resistive carbon compound and a wiper that’s attached mechanically to the shaft, and electrically to the middle terminal. As you turn the shaft, the wiper will move across the resistive compound, increasing the resistance between one of the outside terminals and the middle terminal. At the same time, the resistance between the other outside terminal and the middle terminal will decrease accordingly to the pot’s taper. This means that the sum of the resistances between the middle terminal and the outer terminals will always be the maximum resistance of the pot. That’s all fine and good, but how do they work in a guitar? That depends on how they’re used. They are commonly used as volume and tone controls, and while the principles are similar, each use has some variables.

If x is the resistance from one terminal to the middle, y is the resistance from the other terminal to the middle, and z is the maximum resistance of the pot, then:

x + y = z

Pots as Volume Controls

Sure, it would be real easy to feed the signal from your pickup directly to your amp, but isn’t it better to have some control over your sound? The most basic way of using a pot in a guitar is as a volume control. Basically, you feed your pickup into the pot, have one terminal send the signal further down the chain (possibly, though not normally, to tone pots or to output jacks), and have the other grounded. The idea is, without any extra resistance, the signal will naturally want to ground itself. As you increase the resistance to ground, more and more of the signal will continue down the rest of your chain. You may notice that, as you turn the volume down, you lose some of the higher frequencies. All electrical components have a small amount of natural capacitance. One of the side-effects of this is that all frequencies will not be effected uniformly by resistance. Higher frequencies will be the first to short to ground, and this is the principle applied in tone controls.

Pots as Tone Controls

It can be helpful to look at tone controls as the inverse of volume controls in function. Where with volume controls you are actually decreasing the signal that’s allowed to pass down the circuit, with a tone control you’re increasing the amount of LOSS to the higher frequencies. The idea is, you connect the tone pot in parallel with the volume pot with a capacitor, and connect another terminal to ground. When the tone pot is turned so that there is maximum resistance across the capacitor, almost no signal is lost, and the effect is nearly negligible. When the resistance decreases, more and more signal is allowed to pass through the capacitor and short to ground. Remember how capacitors effect different frequencies in different ways? In effect, a capacitor is a large resistor for lower frequencies, and provides almost no resistance at all for higher frequencies. This means, that as you turn your tone down, the higher frequencies will be shorted to ground much faster than the lower frequencies, which will pass relatively unhindered to your output jack. Now, there are other ways to install a tone control in a guitar, but the idea of using a capacitor to ground high frequencies is the same.

Now that’s the basic idea behind volume and tone controls. I’m not going to bother with wiring diagrams, because I’m not trying to describe how to install them, but rather what they do. Now, let’s say you have to replace a pot! There’s a lot of different kinds available. How does the taper need to behave? How resistive does it need to be? How long does the shaft need to be?

Audio Taper and Linear Taper

The taper of a pot refers to the rate at which the resistance changes as you turn the knob. Look at your guitar amp. Have you noticed that most of the volume is either in the first quarter turn of the knob, or the last quarter turn of the knob? That’s because the volume control is designed using an Audio Taper, or logarithmic pot. It does not respond even across its range of motion. This is the most common type of pot used to volume controls, because the taper corresponds to the way that our ears perceive volume, which is not even.

A Linear Taper pot responds evenly across its whole range of motion. At half-way, resistance will be half, at 3/4, the corresponding resistance will be 3/4 (while the other terminal will be 1/4). The graph of the relationship is a straight line. Many people like a Linear Taper tone control, but this is mostly a matter of taste. By and large, the most common taper used in guitars (both volume and tone controls) is the Audio Taper.

Resistance

I could easily dedicate an entire article to the topic of potentiometer resistances. This is the single potentiometer variable that will most effect your tone. What resistance you use will largely be a matter of taste, but there are a few “starting points” depending on what kind of pickups you have.

If you have lower-impedance pickups (ie. low-output single coils) you’re probably going to be looking at pots in the 100,000 ohm range. If you find that your guitar’s tone sounds muffled and squashed, you can try 250k ohm pots, but you may find your sound turning much too brittle.

Medium impedance pickups (ie. high output single coils & low output humbuckers) generally sound best with 250k – 330k ohm pots. With some, you may be able to justify 500k ohm pots, but again… Depending on your pickups and taste, you might find that too brittle.

Higher impedance pickups (ie. modern humbuckers) can scrape by with 300k ohm pots if you like the dark tone, but you’ll get much more clarity at 500k ohms. This is especially the case with modern pickups that are designed to be “hotter” versions of Gibson’s “Patent Applied For” humbuckers of the late 1950s.

Very high impedance pickups (ie. modern metal passive humbuckers) generally behave well with 500k ohm pots, but you might find that 1,000,000 ohm (1M ohm) pots work for you.

You can also experiment in using different resistances for your volume pots and tone pots. The above applies primarily to volume pots, but since tone pots are normally wired in parallel to volume pots, their resistance counts too. In effect, if you made the capacitor a regular wire, a 500k volume pot and a 500k tone pot would provide a resistance of 250k ohms. For this reason, some people actually cut their tone pots right out of their circuit, and leave only the volume pot to provide a full 500k ohms for very bright (possibly harsh and brittle) tones.

If v is the resistance of the volume pot, t is the resistance of the tone pot, and R is the total resistance, then in parallel:

1/v + 1/t = 1/R

Shaft Length

There’s not much to say about the shaft length of a potentiometer. What do you need it to stick through? On a Strat, where you only have to stick through the thin material of the pickguard, you don’t need a long shaft. On a Les Paul, you have a fat piece of carved maple to stick through, and you’ll need something longer.

Push-Pull Pots

Remember when I was rambling about Jimmy Page at the start? He achieved much of his tonal depth by using a push-pull potentiometer. Basically, they have several banks of terminals, and allow you to use them in different configurations. You switch between configurations by pushing or pulling the shaft. Using push-pull pots you can tap individual coils from a humbucker or switch between parallel and series pickup configurations.

Make It Work For You

The potentiometers are just the gateway to all kinds of fun experiments with a guitar. People modify their pots with nail polish, cut them right out of the circuit, wire them together in different way… Any interesting configuration that works, you can bet people have tried, all in the search for that holy grail of tone. People look for vintage bumblebee capacitors to go with their 500k pots, and buy pickups that they can coil tap with their push-pulls. You can get caught up in all the racket very easily, trying to find the perfect electrical components to brighten up your sound, or mellow it out. Let the music flow from your fingers, and I know you’ll be impressed, no matter what’s in your axe.

On our next outing, I’d like to look into something that’s useful for any guitarist to know. Keeping your fingerboard clean, buttery, and beautiful can be a stressful job, especially when you live in dry or humid climates. If you don’t clean it, it gets covered in grime… That doesn’t help your playing any. If you clean that grime off, it may dry out. At best, a dry fingerboard is just pale and ugly. At worst, it may begin to crack or chip, or your frets may go loose! We’re going to take a look at how to keep your fingerboard, rosewood or maple, in shape.

This article is open for discussion on the Studio Central forums:
Discussion

Well, Wrap My G-String!

Tuesday, February 27th, 2007

I remember when I first started seriously playing guitar. I was dedicated to learning how to set it up properly by myself. No sir, I wasn’t going to be relying on the clerk at Long & McQuade. So, when it came time to change ‘ol Misty’s strings for the first time, you can imagine how stupefied I felt when asked what kind of strings I wanted.

Umm… Acoustic?

What Brand?

Ahh.. D’Addario! Those look good!

What gauge and alloy?

Eh? What and what?

Yes, there are many different kinds of guitar strings out there. This article focusses primarily on the various types of acoustic strings and how they can play games with your sound.

So, what are an acoustic guitar’s strings made out of? When I was in high-school, all of the poor schmucks who thought they knew something about the guitar would shout out “Steel! Duh… They’re STEEL-string guitars, dummy!” I had the pleasure of smacking those ignorant people. By and large, the primary material used to make strings for acoustic guitars is a metal alloy called Brass (OFTEN falsely called Bronze).

Brass is made by combining the metal elements Copper and Zinc. Bronze is an alloy of Copper and Tin. So those ignorant teenagers back in high-school should have been calling their axes “Brass-string guitars”. Even then, not all Brass is made equal! So the alloy is made from Copper and Zinc, who cares? How much copper, to how much Zinc? When I was a young kidd-o, my dad put in a basketball hoop on the driveway. When it came time to cement the post into the ground, my little cousin was playing with the hose. The result was a concrete mix thinner than the material of a teen pop-star’s dress. How much of each metal goes into the alloy is a factor to consider. Let’s look at a couple of common alloys used for guitar strings.

80/20 Brass

80/20 Brass is easily the most common alloy used. 80/20 means that the alloy is made 80% of Copper and 20% of Zinc. 80/20 yields a rich, vibrant, and very bright tone. That ringing acoustic sound on most of your favorite folk albums (come on.. I live and die by James Taylor) is a characteristic of a fresh set of 80/20 strings. 80/20 does suffer from a major drawback though. After even an hour of playing, a fresh set is significantly duller. I changed strings a dozen times one particularly grueling day during a recording project as the result of a crowded, hot room and too much string-killing, acidic sweat.

Do you eat eggs for breakfast every morning? Has anyone called you a carnivore because of the ammount of meat you consume? You may be shortening the length of your guitar strings just by your eating habits. High protein diets usually result persperation with a noticable reduced pH. Yes, acid sweat, that eats away your strings. You can help to fight this by drinking lots of water and cleaning your strings with a dry cloth after every use.

Phosphor Bronze

Okay.. so there really is some truth when they say guitar strings are made of Bronze. Phosphor Bronze is the minority leader (by a MASSIVE margin) for acoustic string market-share. It’s a true Bronze alloy, made of three elements. Phosphor Bronze is almost entirely Copper, with Tin levels approaching 10%. In addition to the two core elements, Phosphor Bronze is generally about 1% Phosphorus. The Phosphorus is added to act as an anti-oxident, and significantly lengthens the life of a set of strings. Phosphor Bronze strings have their own tonal characteristics. They tend to be beefier and not as bell-like as 80/20 strings. Powerful guitar licks that drive the music are well suited to Phosphor Bronze strings.

In addition to the alloys available, you can get acoustic strings with special chemical coatings. These coating are designed to stop grease and sweat from oxidizing the metal of the strings. While it’s hard to deny that they significantly increase the longevity of a set of strings, it’s a common argument that chemical coatings kill the tone of the strings. This effect becomes especially pronounced as the string shape is worn from contact with the fingers and the frets. The shape-change is exaggerated by the presence of the chemical coating, and the string vibration is altered even more than with a standard 80/20 or Phosphor Bronze set.

Classical Strings

Okay, so they aren’t for “Steel-string guitars”, but classical guitar strings are certainly made for acoustic playing. They used to be made from cat’s guts, or horse’s hair. Today, classical guitar strings are made of nylon, and the three bass strings are usually a nylon core wrapped in a non-magnetic silver-containing alloy. Nylon strings lack the ringing an sustain of metal strings, but create a very exotic, short, middy note when plucked. When skillfully strummed, many beautiful flamenco styles evolve.

Okay.. So you know what alloy you’re after, but what was that other thing the clerk needed to know? Oh yea, what gauge do you need? Strings come in many different thicknesses. Acoustic guitar strings tend to be significantly fatter than electric guitar strings. With this increase in size (and a difference in material) comes a very large increase in string tension. It’s usually much harder to press the strings on an acoustic guitar than those of an electric. A larger string is capable of producing more volume (especially important for an acoustic guitar, where the fundamental volume of the string is amplified by the construction of the guitar) and also gives off a fuller representation of frequencies. As an analogy, think of two equal quality speakers, one 10″ and the other 12″. The 12″ speaker will more easily produce the rich lower frequencies that fill out the sound. While the principle at work in the case of a guitar’s strings isn’t quite the same as that at work for the speakers, you get a similar effect.

String gauges are usually labeled by the size of the first (high E) string. For example, most standard light gauges are referred to as “12s” because the first string is 0.012″ wide. This can be confusing though, when you take into account that not all manufacturers make all of the other strings in a set of 12s to match. Furthermore, there are “top-heavy” sets, where the four heaviest strings are even bigger than normal!

As if that weren’t enough, some sets have a wound G string (I hear you laughing already), while others leave it plain, like the two treble strings. A wound G usually helps with intonation, and can contribute to producing a balanced sound, though many prefer it plain.

“So, I was playing this show once and I broke my G-String right up there on stage! I didn’t have a spare axe, so between songs I had to unscrew my nut, lift my bridge, put a new G-String on, and tighten my nut back up again! Right there on stage!”

- Randy “The Randy” Haley

Make It Work For You

So whether you like them big or small, made of hardened bronze or soft nylon, wound or unwound, there’s a set of strings for you. They all have noticeably different characteristics, but luckily, strings are something that you can experiment with. Try the different sizes (you may need a new nut cut) and alloys and see what you like the best. All the while, don’t get too caught up in the pursuit of the holy grail of strings. If you’re a musician, focus on the music first and all the tone that you could possibly want will come dripping from your fingertips, regardless of what strings you use.

From one extreme to the other, next week we’re going to take a look at the component that most touches the sound of an electric guitar after the pickups. That’s right, get a party bowl ready because we’re going to get deep into potentiometers. (Those little knobby things)

Have anything you’d like to add? This article is open for discussion at the Studio-Central Forums:

Discussion

‘Tonewood’ – Not Just a Dirty Word!

Sunday, January 21st, 2007

Has anyone ever asked you what your guitar was made out of? Did you consider what it was made out of when you bought it? Many players, especially those gleefully wanking away on their first axes don’t realize what their babies are made of, or how it contributes to their sound. Today, I’d like to take a look at some of the most common tonewoods used in the construction of guitars, both acoustic and electric.

So what exactly is a tonewood?

“Tonewood. Tone-wood.. Tone Wood… Is it when you hear a trigger sound and your…”

No! No, that’s certainly not it! Tonewood is actually a deceptive name. All woods are tonewoods. That is, they all have certain properties that effect the manner in which they resonate and transfer that resonation. The more common tonewoods have properties that make them attractive choices for use in instrument building.

This article will provide a primer on the physical and tonal properties of the most common tonewoods, as well as an idea of which ones common guitars are built out of. I’ll also throw in my unwanted opinions too, just to make things more scandalous. So without any further gabber, on to the show!

Alder

Alder is the not-so-secret weapon of many electric guitar manufacturers, especially those in the USA. Physically, it is a light (both color and weight), tight-grained wood that takes stains, dyes, and finish very evenly. It has a very acoustic natural resonation, and is used extensively in solid body electric guitars for its emphasis on bright, punchy sound. Alder isn’t extremely hard, and you can very easy put marks in it if you aren’t careful. I personally love the look of a worn out alder guitar thats finish has stripped, allowing sweat to soak into the unprotected wood-grain. But then, I’ve been told that I’m sadistic.

So who builds with alder? Are you kidding? You can find alder guitars in the line-ups of Jackson, Fender, Yamaha, and Squire. Among others. Many, MANY others.


Alder’s a classic

Ash

If alder is the hottest, most shallow drunk chick at the party, ash is her best friend. You know, the one taking a footing behind her friend, not wanting to cause such large ripples. The one with her own intellectual quirks that drive you wild. Ash can vary widely in properties, and for this reason it’s usually divided into two separate species. I guess that would make the girl in the analogy a skitzo, wouldn’t it? Swamp ash is slightly heavier than alder and generally exhibits patterns of dark brown streaking. Tonally, it is similar to alder with a noticeable increase in upper-midrange frequencies. The second, less common species of ash is heavier yet, and exhibits a brighter, more ringing tone.

Swamp Ash was the tonal champion of Fender all through the 50s. It was commonly used on all of their guitars. Today, the stereotypical ash guitar is the Telecaster. It is also highly prevalent among Japanese made guitars, especially through Fender’s Japanese era, due to its availability in Asia.


Ash, beautiful with nothing on

Poplar

Poplar is used in the construction of guitars for one very good reason. It’s cheap. Physically, it’s a tight-grained wood that weighs slightly more than alder. It takes finish very well, and finish it you should. Without some kind of color, it looks like watered-down green/yellow puke. Tonally, poplar exhibits similar properties to that of alder. It lacks the elements that give alder its cutting edge, however.

You can find poplar guitars with many names on them. Perhaps the best way to illustrate what role poplar has been designated as a tonewood is this: Squire


Puke.. err. Poplar

Basswood

A good cut of basswood is extremely light and nearly white. A bad cut is full of dark streaks that don’t seem to hide very well behind any kind of finish. And speaking of finish, you better have lots if you want to finish a piece of basswood because it will absorb it faster than a kid juiced up on Redbull will try to jump off the bookshelf! Don’t expect to take a basswood guitar with you to your grave either if you’re as abusive of your axe as most are. Basswood will mark just by tapping on it. Of course, it has some favorable tonal properties. It tends to have an almost hollow reverberation while resonating, and gives off a deep, smooth tone.

Basswood is an application specific tonewood. It’s fairly inexpensive, making it a common appearance in Squire’s lineup, but its tonal properties also win it use in the more rhythm-oriented offerings from Ibanez.


Fragile basswood

Mahogany

My favorite wood of all time, and not only for its tonal characteristics, mahogany is one of the market mainstays today. The most common species used is Honduran mahogany. Physically, it’s a relatively light-weight hardwood with a rich red or brown coloring. It’s open grain often leads to thin black speckles that create a sense of depth. It takes finish, but you need to prepare it more extensively than other woods. As a tonewood, mahogany provides for as rich a sound as it does a smell. Mids and lows are accentuated, and the wood vibrates in a way that reminds me of a tender encounter with true love.

Mahogany is used almost as extensively as alder. Perhaps the most prevalent manufacturer using mahogany is Gibson, but Paul Reed Smith, Ibanez, Yamaha, Epiphone, and many others are on the same boat. Incidentally, the wood is used both for electric guitars and acoustic guitars to similar effect.


Mahogany! My love!

Maple

Maple is the almighty balance in the universe. It’s an extremely heavy wood, and playing a guitar made entirely out of maple is like asking your chiropractor to cause back-pain. It can vary greatly in appearance, exhibiting remarkable cross-grain patterns that resemble flames, tiger’s stripes, bird’s eyes, or ripples in water. Maple is also very hard. Getting hit by a maple pole resembles getting hit by a steel pole in many ways. Yes, I have firsthand experience on this matter. Tonally, maple is very bright, almost shrill. Maple fingerboards and necks tend to brighten up a guitar’s sound.

Very few guitars are made exclusively from Maple, largely due to its weight and tonal properties. Cost is also a major factor, as this wood doesn’t come cheap. Gibson’s Les Paul uses a slab of carved (and often beautifully figured) maple as a soundboard, to bring balance to a mahogany back. ESP follows a similar principle with their guitars, as does Paul Reed Smith. Maple fingerboards and necks are used by many manufacturers, including Fender.


Sweet tiger maple!

Korina

Korina is all the rage in the guitar building community. It can come very light, with a nicely streaked off-white color that suits natural finishes very well. This is good, because its waxy surface makes it hard to dye. Where its real power shows is in its tone. It exhibits tonal properties much like that of Mahogany. For aging Les Paul players who don’t want to dislocate their shoulders with eleven pound guitars, korina is an interesting idea.

Korina is used by many independent builders, but is largely shunned from mass production. Some major names produce lines of basses built from Korina.


Korina, like a forest

Spruce

Spruce is an extremely light softwood with a long straight grain pattern. It often exhibits knotholes, which either need to be worked around, patched, or used as character. Tonally, spruce is bright and punchy with plenty of volume when used as an acoustic guitar’s soundboard.

Most builders of acoustic guitars have some models with spruce (usually Canadian Sitka Spruce) soundboards. These include Martin, Taylor, Cort and Yamaha.


Spruce.. or, sand?

Cedar

Cedar shares many physical properties with spruce. It can range in color from a deep red all the way to white. Cedar tends to produce a warmer, more whole bodied sound when used as an acoustic soundboard.

Classical guitars like those made by Almanza, Yamaha, or Jasmine (By Takamine) make extensive use of cedar as a soundboard material. Some larger guitars take advantage of the overall loudness of cedar, including the concert jumbo class guitars from Cort.


Rich red cedar

Bubinga

Bubinga is often called African rosewood, but it’s from an entirely different species. It is very heavy, somewhat waxy, and usually has a purple tinge to it. Its figuring can be breathtaking. I have a 2″ board of bubinga sitting downstairs just waiting for me to get a larger bandsaw so that it can be resawn and made into my new coffee table! Tonally, bubinga exhibits many of the characteristics that rosewood does.

Bubinga is nowhere near as commonly used for guitar bodies as rosewood, but it is a common sight on cheaper guitars that claim to have a rosewood fingerboard.


Plain-Jane bubinga

Indian Rosewood

Indian rosewood is what most people refer to when they say rosewood. It is a dark wood with a mix of browns, reds, and purples, and can display intricate grain patterns. It is very heavy. Like many exotic woods, its waxy surface makes it difficult to finish. Tonally, rosewood is warm and rich with an unusual amount of bite.

While you’re more likely to find rosewood on a guitar’s fingerboard, it is also used as a body wood by builders like Fender. Their rosewood telecaster rocketed to instant fame due to its ties to George Harrison and the Beatles’ Abbey Road. Indian rosewood is also a common sight on acoustic guitars, which take advantage of its properties to provide much more bite and cutting tone than Mahogany gives.


I love India for the rosewood

Brazilian Rosewood

Brazilian rosewood is the thing of legends. It’s the holy grail of guitar tonewoods. It is physically very similar to Indian rosewood with an even more elaborate grain pattern and a wider range of colors that combine to make true beauty. It is also very waxy, and hard to finish. All the warmth of Indian rosewood is there, with new frequencies that cut through like no other.

While Indian rosewood is occasionally used for guitar bodies, Brazilian rosewood is not. It is extremely expensive, and illegal to forest or export from Brazil. This is strictly a fingerboard wood. And is it ever. I have had the pleasure of playing 3 guitars sporting Brazilian rosewood so far, and I must say that its a pleasure to play on. That said, I reside myself to accepting that I will never own a guitar like that. In the not too distant future, Brazilian rosewood fingerboards will join ivory nuts as extinct guitar legends.


Brazilian rosewood, exotic

Ebony

Ebony is a very hard, very black wood that screams “too cool for school” when you see it on a guitar. It’s very heavy, and nearly pointless to finish. If getting hit by a maple bat is like getting hit by a steel poll, an ebony bat is like a front-end loader! Tonally, ebony is very bright and can contribute to making a guitar shrill sounding if its not built for tonal balance.

Ebony is highly used as a fingerboard material by such manufacturers as Gibson. It’s rarely (ever?) used for bodies because, well, you try holding thirty pounds on a one-inch leather strap over your shoulder for four hours!


Black magic, ebony

Make It Work For You

There are many other tonewoods that I’d be happy to discuss, but even some that I presented here push the border between common and obscure. Does any of this mean that your guitar from Walmart made out of the famous tonewood “Godknowswhat” sounds any worse than other guitars? No. Every part of a guitar contributes to its tone, but what oozes out of your fingers is you! The way you play will make your tone, no matter what your instrument is made out of.

Wow, that was long, wasn’t it? Why don’t we take it easy next time. I think I’d like to take a little trip to a place called “Acoustic Land” where we’ll look at all of the different kind of strings available, and how they’ll affect your playing.

Have anything you’d like to add? This article is open for discussion at the Studio-Central Forums:

Discussion

Tighter Coupling? I’m Not That Kind of Bridge!

Tuesday, January 16th, 2007

Today we’re going to get our hands dirty and explore two very interesting variations on the traditional set-up of an electric guitar’s bridge and tailpiece. Why would anyone want to screw around with tried and true pieces of hardware such as those? Believe it or not, there are people who are just as obsessed with getting as much tone out of their guitars as you are with getting the most out of your DAW. Both of these variations require nothing more than common around-the-house supplies and a little bit of motivation. For you Gibson readers, the first variation is commonly known as the “Tailpiece Wrap”. For the second variation, we’ll be jumping to a different kind of bridge entirely, and blocking a Fender style Tremolo. The primary goal of both of these is to increase the coupling between the bridge, tailpiece, and guitar body.

Coupling

Coupling is a concept dealing with the level of connection between any two tone-bearing parts of a guitar. As the tone is generated by the strings, the first two points of coupling are the points where the string touches the guitar. These are the fret-wire of the played note, and the bridge saddle. The bridge saddle transfers vibrations into the bridge, which transfers into the guitar’s body. On a guitar with a tailpiece, sympathetic notes are generated on the sections of string that extends beyond the bridge toward the tailpiece, and the process is repeated here. Guitar audiophiles painstakingly try to maximize coupling at all points.

The Tailpiece Wrap

On Gibson’s ABR-1 and Nashville style bridges, there’s not much room for good coupling. The bridge is dropped into place on top of two studs that are mounted in the body. These are the only contact points between the body and the bridge. The bridge cannot be lowered enough to come into direct contact with the body of the guitar. To increase coupling on these guitars, the only avenue available is the tailpiece. Its job is to anchor the ends of the strings in place and create a suitable followthrough angle for the strings after they clear the bridge, so as to produce enough string tension. The short length of strings between the bridge and tailpiece ring at sympathetic frequencies to their longer counterparts, and so coupling the tailpiece becomes important. In most cases, you can’t simply screw the tailpiece down against the body of the guitar. This will generally put too much tension on the bridge, and cause it to collapse. A collapsed bridge is not the end of the world, but it does mean a trip to your luthier or your trusty shop-vice. If you want to screw the tailpiece down all the way, you’ll need to find a way to reduce the angle at which the strings fall away from the bridge.

Angle

The angle at which the strings leave the bridge is important. Too great an angle, and you run the risk of collapsing your bridge. If the angle is too shallow (as demonstrated here) you run the risk of unsetting the low E string whenever you strike it hard.

The solution to this problem is the Tailpiece Wrap. By feeding your strings through the tailpiece backwards, and wrapping them around the top toward the bridge, you can screw the tailpiece all the way to the body of the guitar and reduce the overall tension on the bridge.

Tailpiece Wrap
The tailpiece wrap is accomplished by inserting the strings backwards through the tailpiece, and running them over the top. Make sure to screw the tailpiece down flat against the body of the guitar.

As with anything, there are a couple of pitfalls to the Tailpiece Wrap. The most serious is when the grooves in your saddles aren’t entirely formed yet. They come filed with a small dimple from the factory that grows as your guitar ages. If you only have the small dimple, the reduced tension from the strings could result in their slipping out of place on the saddle. In some cases, they could even slide right off of the saddle. You can “expedite” the groove-setting process with a small file if you wish, but any change you make will require you to reset the guitar’s intonation. The other major consequence of the Tail Wrap is a matter of preference. Your strings will feel slinkier as you play due to the decreased tension. It might be just what you need to bump up to the next gauge of string though.

Pitfall

This is what you can expect if you have your bridge set for very low action and havn’t worn deep enough grooves into your bridge saddles. You can attempt to file the grooves deeper, but you’ll need to reset your intonation.

Blocking Your Tremolo

There are many manufacturers of tremolo bridges today. The comments I make here refer specifically to Fender’s classic and modern style tremolo bridges, but can be translated to most. Pictures will become available the next time I work on someone’s Strat, I sold my last one a few months ago.

A Strat is a guitar tweaker’s delight. They’re pieced together from several completely different parts, in a manner that makes the tightly integrated guitars of Gibson look like solid marble statues. It’s no wonder that they have a characteristic sound that’s nothing like more solidly built guitars, but wonderful in it’s own right. Their tremolo bridges allow for some creative pitch-bending, but can be a big hassle if you don’t use them! Ideally, the bridge will be lifted off of the face of the guitar a fair amount. In order to sustain the string’s vibration, there’s a solid metal block bolted to the back of the bridge plate where the strings are anchored. Not only does this make for bad coupling, it causes problems with tuning. Whenever you change the tension on one string, all of the others will change as a result of the floating bridge. Break a string and you’ll go hideously out of tune. To solve both of these problems, we’re going to put a Strat on the operating table.

To block the tremolo bridge of a strat, lower the tension on all of the strings evenly until the bridge lies entirely flat against the face of the guitar. Open up the back compartment by removing all of the screws on the vinyl plate and take a look inside. Some people like to make this a natural reverb chamber by installing all five of their tremolo springs and screwing the claw as far up as it will go. This isn’t necessary in order to block the tremolo. You’ll need a solid, shapable block. A piece of hardwood works wonderfully here. You’ll need to shape it to fit between the metal block behind the tremolo, and the guitar’s body at the bottom of the tremolo cavity. Sand it so that it fits very tightly in this space. This will provide solid coupling between the bridge’s sustain block and the body of the guitar. It will also prevent the bridge from shifting when the string tension changes. It’s common practice to drill a pilot hole in the block so that you can insert a screw that can be pulled with a pair of pliers if you ever decide to remove the block.

What do you lose by blocking your tremolo? Well, you can’t do any more dive-bombs, and porno music is out of the picture! If those aren’t your things, it’s not hurting you much and it can always be removed.

Make It Work For You

So does all of this coupling mumbo-jumbo mean anything to you? Even if you don’t buy it, both of these bridge variations are worth a try. They’re easily reversible and don’t require any unusual materials. I personally don’t like the looser feel of the strings when wrapped around the tailpiece, and I play 11s. To me, the shorter Gibson scale length loosens the strings enough. I do wholeheartedly encourage the use of a blocked tremolo if you don’t use it on the other hand. At the end of the day, both are just ways to tailor the feel and flavor of your axe. Find what’s right for you.

Next time, I’d like to venture into the world of guitar tonewoods. It’s sure to be exotic!

Have something You’d like to add? This article is open for discussion on the Studio Central forums:

Discussion

Further Reading:

Dan Erlewine’s How to Make Your Electric Guitar Play Great,
ISBN:10 – 0879306017
Dan Erlewine’s Guitar Player Repair Guide,
ISBN:10 – 0879302917

Money Shot This is nothing more than a self-satisfying moneyshot of my beauty and the star of this article. Again, I promise to get Strat pictures up as soon as I work on someone’s strat.

Magnetic Guitar Pickups, ‘How’d They Do That?’

Monday, January 15th, 2007

With the SC community beginning to expand into new horizons, it’s my honor to bring you this, the first installment in a series of articles focussed on the technical aspects of guitars. I have grand plans for articles covering electronics, tonewoods, getting the most out of a guitar, set ups, and even elements of guitar construction. You can expect both light reading acticles like today’s, as well as in depth detailed information with photographic support.I thought I’d start our journey with a nice light historical article on a topic that I’ve always found fascinating. Guitar pickups have revolutionized the way that we make music. While most of us weren’t around to witness the catalyst of this change, we’ve all seen first hand how music has evolved as a result. I’d like to shed a little light onto their history, how these wonderful inventions work, and offer some advise on how to go about getting YOUR sound out of them.

Development

While there are many different types of pickups available today, the passive magnetic pickup is undeniably the industry mainstay. They are the driving force in everything from jazz, to rock, to NUmetal (uggh). The first known magnetic pickup was created by George Beauchamp and Paul Barth in 1931 for Rickenbacker, and was used in an aluminum guitar! It operated on a very simple principle, induction. Cutting through the finery, you take a magnet (or magnets) and wrap it thousands of times over with a thin copper wire. The strings of the guitar (made from a magnetic alloy) move and vibrate inside of the magnet’s field creating electric current in the wire at the same frequency as the vibrating strings. This signal is fed to your amp, and hey! Bob’s your uncle!

Field Diagram

Magnetic pickups have a near infinite variety! Lipstick tubes, soapbar P90s, dogear P90s, single coils, humbuckers, mini humbuckers, the list goes on. All have their own characteristic sounds that are influenced by the differences in their constructions, but they all fall into two categories. Single coils and humbuckers.

Lipstick TubeLipstick Tube Single Coil

Single Coils

A single coil pickup is not much different than the general description that I provided earlier. Most Fender style single coil pickups actually have six separate magnets, (1 under each string) where a P90 has 1 long magnet and a shorter bobbin. The bobbin is the piece of plastic around the magnet. A taller bobbin places the copper wire closer to the magnet, creating a brighter sound. Single coil pickups tend to provide a lower output than a humbucker, and a clearer, stronger representation of the higher frequencies. Since they are basically glorified antennae, they are highly susceptible to RF interference, especially 60Hz hum from fluorescent lights or electrical lines.

Strat SinglesFender Strat Single Coils

Humbuckers

The humbucker was invented by a scientist working for Gibson in 1956. His name was Seth Lover, and his creation first adorned Gibson’s 1957 line of guitars. He flipped the magnet in a pickup and wired it backwards to a normal single coil. The result was a reinforced signal with greatly reduced electrical interference! By wiring the pickups together backwards, he had two near-identical electrical signals (with interference) combining out of phase and canceling each other off. By flipping the magnet, he reversed the polarity of the induced current on the second pickup so that it was in phase with the first. Since the interference exists in the copper wire, not in the string’s vibration, his humbucker generated a strong signal without the noise.

Humbuckers tend to produce a very powerful, dark signal. With today’s demand for more powerful pickups, wax potting has become a common practice in humbucker design. The copper wire is covered in wax to reduce the microphonic qualities of the pickup, qualities that can easily lead to squeal and feedback if not controlled.

Patent
The patent filed by Seth Lover for the first humbucker

Make It Work For You

Because a pickup is a magnet, it can have an effect on the vibration of your strings. Many intonation problems, or the sudden loss of sustain can be solved by backing the pickups away from the strings. This is usually accomplished by turning two screws on either side of the pickup. Experiment a little bit here, there’s not much you can harm. See just how high you like your pickups. The closer you get to the strings, the stronger the signal will be. You will also notice the magnetic effect of the pickup on the strings more. Humbuckers can generally be positioned much closer to the strings than single coil pickups. If you have adjustable pole pieces, you can experiment even further. The most common practice is to adjust them to follow the heights of your strings, but you can custom tailor your sound this way. Remember, there’s a 1:6,900,000,000 chance that you aren’t Jimmy Page. The pickups are just a tool for your creativity, you have to find your sound.

Next week, I’d like to take a step away from both electronics and the history lesson, and bring you some great tips on how to get the most out of your bridge/saddles, and (if applicable) tailpiece! And if that wasn’t enough, you’ll get to see pics as I illustrate it all on my Les Paul.

Have something you’d like to add or explore further? This topic is open for discussion at the Studio Central forums:

Discussion

Further Reading:

Donald Brosnac’s Guitar Electronics for Musicians, ISBN:10 0711902321