Does it bug you to lose treble when you roll back the guitar volume? Here are three solutions to that problem.
Passive single-coil pickup systems have an inherent sonic idiosyncrasy: When you turn down the volume—even just a bit—the high-end loss is not proportionate to the volume reduction. In other words, a small cut in volume creates a far greater drop in your guitar's treble response. This is true of the Stratocaster and Telecaster, as well as many other popular models, so I'm sure you're familiar with it.
This quirk of passive electronics isn't really a big deal for all players. Many aren't bothered by it because they've simply gotten used to the sound over the years. Others really like this "problem," since it lets you coax a second tonal color from the same pickup—simply roll back the volume a tad to fatten up the tone. But a lot of guitarists (myself included) prefer to maintain an identical amount of treble at any volume setting.
Using active electronics is the only real solution to combating the "volume-versus-tone" issue—all other strategies are just a compromise. That said, compromise can lead to significant improvements. Personally, I use a compromising solution in all of my own guitars. And my favorite solution is one of the easiest mods ever: add a "treble-bleed network" between the input and output of the volume pot(s) of the guitar. This works with passive single-coils and humbuckers, but if your guitar has more than one volume control, like on a Les Paul, each volume pot needs its own treble-bleed network.
Some Background.
So, what is a treble-bleed network and how does it work? In layman's terms, it's usually a combination of a small capacitor and a resistor in parallel. Techies call this a RC network, but such systems are also called a "treble bypass filter" or TBA, for treble-bypass arrangement. You can also find variations that use only a cap, or a resistor in series with the cap.
The theory behind this little rascal appears straightforward, but it's much more complicated than it seems. So as not to slam you with theory, I'll stick to the basics, which means having to over-simplify the following explanation.
First, the good news: It's possible to calculate the values for a treble-bleed network that will work superbly in a given guitar. The bad news? The formula behind it is complex and beyond the scope of this column. There are many parameters involved in this formula, such as the number, ratio, and resistance of the pots in your guitar, the pickups, the length and capacitance of your guitar cable, the input impedance of your amp, and more. All of these must be calculated in the context of a Fletcher-Munson curve, which defines equal-loudness contours for the human ear. Doable, but really complicated!
Typically, you have to make several simulations and analyze the corresponding curve to see if it matches your goal. Such calculated networks will work wonderfully in the guitar you calculated them for, but when you change one of the parameters—like the length or type of your guitar cable, or you plug into a different amp—the treble-bleed network will stop working perfectly. That's an unavoidable fact. Because of all the parameters involved, it's easy to see why standard "one-size-fits-all" networks are an illusion.
So you can experiment to determine what you like best, based on your own gear and sonic goals, I'll describe the different types and possible value ranges of the components. Because the range of these components is very limited, at minimum you'll achieve good results. But if you want great results, it's important to realize you'll have to experiment with each individual guitar, and this includes a lot of component swapping.
When you roll down the volume, the treble-bleed network starts to filter out some bass frequencies, making the highs more prominent.
The Details.
When you roll down the volume, the treble-bleed network starts to filter out some bass frequencies, making the highs more prominent. It won't boost anything (treble, in this case) because a passive device can only filter out certain frequencies. The networks are always connected between the input and output of the volume control, as shown in Fig. 1.
There are basically three different types of treble-bleed networks (Fig. 2), and we'll examine each of them. On the left is "cap only," which isn't a true network because it's a capacitor without a resistor. Fender made this version popular in the '60s when they started installing a 1000 pF cap on Telecaster volume controls. Together with the 1M pots they used at this time, the sonic result was kind of creepy ... thin and bright.
This value is still popular today in many one-size-fits-all solutions. This circuit has one problem: As the volume is turned lower, more of the higher frequencies will predominate—even to the point where the guitar starts to sound very "tinny" as the volume approaches zero. Depending on what you're after sonically, this can be a good thing or not. If you want to experiment with this cap-only configuration, good working values are from 220 pF up to 1500 pF.
Our second type of treble-bleed network is shown in the center of Fig. 2. This consists of a cap with a resistor in parallel. This is the version you'll find in most treble-bleed networks. A very popular combination is a 1000 pF cap with a 150k-ohm resistor in parallel. This works for almost any guitar, when it comes to a one-size-fits-all solution.
Fig. 2
The cap-with-resistor-in-parallel version can be superior to the cap-only method because, as you turn the volume lower, the higher frequencies don't dominate. The problem with this circuit is that it affects the taper of the volume pot in a negative way when the two values are not carefully matched to each other. Good working values to try are from 220 pF up to 1500 pF for the cap, and 100k-ohm up to 330k-ohm for the resistor.
Our third treble-bleed network, shown on the right, consists of a cap with a resistor in series. This configuration became popular in the '90s when Australian luthier Chris Kinman started to use a 1200 pF cap and a 130k-ohm resistor in series for his guitars. This scheme is regarded by many to be the best of the three versions, because it seems to solve the problem of the volume pot taper and the tinny sound. Even Fender uses it now. Their system employs a 1000 pF cap and a 130k-ohm resistor, and is dubbed the Fender Tone Saver. Values you should try are 470 pF up to 1500 pF for the cap, and 100k-ohm up to 330k-ohm for the resistor.
Regarding the two components, here's a rule of thumb: Brightness is determined by the resistor's value (less ohms yields more highs), but the frequencies that are present are determined by the cap's value—the lower the value, the higher the frequencies, and conversely, the higher the value, the lower the frequencies.
Into the sound lab. To conduct your own treble-bleed network experiments, solder two wires to the input and output of the volume pot and connect alligator clips on the other ends. If you let the two wires hang out from under the pickguard for fast access, you can easily try every combination of cap and resistor. (Be sure to take notes.)
After you find your favorite combination, remove the two wires and permanently install it to the volume pot. Remember, what you choose may be very different from another player. Some like more high end (this is often due to a dark-sounding amp), while others prefer more midrange to get a punchy sound. It's worth taking the time to try several combinations. This simple circuit can turn a muddy-sounding guitar into an articulate one—even with tons of distortion—because the tone will clean up when you roll back the volume.
I can't advise you what to use—you need to explore this yourself or let an experienced tech calculate your personal treble-bleed network, based on your specific rig. Many guitarists like the cap-only version for Strats and Teles, while others prefer a cap and a resistor in parallel. The resistor-in-parallel and resistor-in-series schemes perform more-or-less equally, but the parallel version offers more highs when you turn down the volume. Again, this can be positive or negative, depending on your pickups and amp.
Okay, that's it for now. Until next time ... keep on modding!
Luthier Dave Helmer shows you how to cure buzzy strings, bad intonation, gnarly frets, high action, and other common troubles with off-the-shelf axes.
Guitars are the best. We love them. It’s fun to fall in love with a guitar at a store, buy it, and proudly bring it home. But we’ve all been there … where after a month that new guitar is just not playing as good as it was before. As guitar players, we know what feels good and what feels bad when it comes to playability. Maybe you have setup preferences that you like on all your guitars, or maybe you want to experiment with changes to your setup?
With a few tools, you can perform a handful of tasks that will make your new axe play better and stay in tune. This article is for folks who already know how to tighten loose parts, raise and lower string saddles or bridges, and adjust their truss rods—though I’ll share a tip on how to check it with even more accuracy.
Is that big bulky stock nut uncomfortable on your hand? Let’s trim it down and reshape it. If the action feels high and the neck looks straight, I’ll show you how to lower the action. And haven’t we all swapped out pickups and wondered, “Do they really sound better, or do I think that just because they’re new?” Before you swap your pickups, I’ll share some pickup-height measurements that might make you change your mind.
But wait! There’s more. With everything feeling and playing great, does moving into the upper register start to sound out of tune? Intonation is very easy to check and adjust. When you go to vibrato or hold a note, do the frets feel “sandy”? Are the fret ends rubbing against your hand while you play? Let’s flush and polish those up.
To be clear, we’re not swapping out anything on your new guitar: We’re simply refining the setup. Be sure to go online to see eight videos I made showing various processes covered in this story.
Begin the Beguine
There is an order of operations for best results. Neck relief is the first item to dial in, followed by getting the nut slots cut to the proper depth. After that, setting your string and pickup heights is in order. The final step is setting intonation.
Fret polishing is its own event and can happen anytime between string changes. Getting the frets feeling comfortable and well-polished will take some time and attention. You’ll also need some specialized tools as well as some that can be found in most households. Check the box for my list.
Tools You’ll Need
All of the specialized tools in this list are available through online suppliers, including StewMac and Amazon.
6" Ruler with measures in 64ths
String action gauge [Photo 1]
Miscellaneous screwdrivers
Allen wrenches
Radius blocks
Understring radius gauges (with the radius on the bottom and the top)
Fret-end dressing file
Micro-Mesh sticks [Photo 2]
Tape (low tack)
Cotton swabs
Paper towels (blue shop towels preferred)
Clean cotton rags
Nut files [Photo 3]
Stikit sandpaper
Tri-Flow lubricant
Capo
Feeler gauges
Simichrome polish
Polishing the Frets
Let’s start with the most Zen of these tasks: fret polishing.
Tape off the fretboard using low-tack tape, exposing only the frets. De-tack each piece of tape on your clothing or maybe a rag—I use my jeans or my sweatshirt. Making it less sticky helps prevent pulling finish off a maple fretboard or the neck. Taping the fretboard also prevents putting any cross-grain scratches into it while you file and polish. You can choose to tape off the entire fretboard or work your way down one fret at a time. Dealer’s choice.
One thing to note about tape, any tape: Even when you de-tack it, you do not want to leave it on overnight. If that happens, rub the tape with your finger, which will break the surface tension. Then carefully pull the tape off from a corner, making sure you’re pulling it off at an angle and not at a straight line with the fretboard edge.
Photo 4
Every fret end has a small burr on the corner from the initial fret job. The fret-end dressing file has a non-marring smooth side for rounding the fret end, and a safe square edge for getting into the corner of the fret end. So, take the fret-end dressing file, use the squared off-side, and file both corners of the fret end [Photo 4].
How to Polish Frets
Here’s how easy it is to polish and smooth frets.
Photo 5
One or two strokes is all you’ll need. Then, using the non-marring side of the file, slightly round off the fret ends. [Photo 5].
Photo 6
With the file positioned vertically, file downward to make the fret end flush with the edge of the fretboard [Photo 6].
Photo 7
For a nice, rounded-off look, polish the frets using the same rounding motion from the previous step, working through all three grits of the Micro-Mesh stick [Photo 7].
Photos 8 (top) & 9 (bottom)
Then, polish both the sides and the top of the frets [Photos 8 and 9]. Using a soft cloth and Simichrome, buff every fret. This will give you a great shine and help prevent oxidation. Now it’s time to remove the tape and condition the fingerboard if it needs it.
Note: Every fret has two fret ends to clean up and polish along with the fret itself. This is a fair amount of handwork. If you’ve never done it, you will get tired and need a break. Take that break. Take multiple breaks. Let the process take however long it requires without rushing. If you’re new, do all the fret polishing over a weekend or a few days. It should be fun, not painful. If it is difficult, call your local luthier and hire them to do it for you.
Adjusting Neck Relief
Neck relief refers to the slight amount of concave bowing intentionally created in the neck of a guitar or bass by adjusting the truss rod. For the safety of the guitar, be sure to slack the strings before doing any adjustments to the truss rod. Neither you nor your guitar needs to be tense during this process.
Photo 10
Before whipping out an Allen wrench for the truss rod, start by sight-checking the neck’s straightness. You can sight the neck with the guitar on its back, but I like to put it on edge and look at it that way. It’s easier to see how much curve there is when the guitar is on its side. I feel like gravity plays tricks on my eyes when I sight the neck with the guitar on its back. When I play the guitar, it’s on its side anyway, so looking at it from this vantage point is best [Photo 10].
Photo 11
Tune the guitar to pitch, put a capo on the first fret, and press fret 15 with your left hand. With your right hand, take a feeler gauge and check the gap at frets 7 through 9 (left-handed players, flip your hands around) [Photo 11].
From the top of the fret to the bottom of the string, the gap is usually anywhere from .003" to .012", depending on the feel you are going for. The feeler gauge should fit just between the top of the fret and the bottom of the string. The string shouldn’t move. This will tell you how much “relief” is in the neck. If you find this challenging, keep going—this will take some practice.
When dialing in the relief, I go back and forth between adjusting the truss rod and the string action. Getting the strings low and playing clean on a budget axe can be a challenge. Usually the fretwork isn’t that great, and in the upper register the frets can be unlevel, causing buzzes and clanks. If you need to raise the string action to get the notes to play clean, some fret leveling may be in order. (For more on fret leveling, go online to our article “About Fret Leveling,” from the December 2007 issue.) For good energy transfer, the neck should be as straight as possible. If the neck is straight and the frets are not level, the strings will buzz with low action.
In general, the flatter the radius on the fretboard, the straighter you can get the neck with the truss rod adjustment. On a fretboard with a 12" radius, you should be able to get .005" relief, and on a vintage 7.25" radius board you may need as much as .014" relief. The only way to get better at checking and setting relief is practice.
Refining the Nut
String buzzes, pinging noises when you tune, strings sticking in the slots, and too much string motion in the nut slots are all indicators of trouble. Before getting out the sandpaper and Micro-Mesh sticks, be sure you know if your guitar’s nut is TUSQ or bone. TUSQ is softer, so you should leave TUSQ nut slots a little higher. This leaves room for the TUSQ to wear without causing buzzing on the first fret. With bone, you can cut the slots lower, because it holds up to string wear.
How to Shape Your Guitar's Nut
Watch as Dave Helmer sands down the back half of a nut and creates a smooth finish.
The back side of the nut is usually very bulky and could often stand to lose some material to be more comfortable on your hand. So, let’s start there. Tape off the neck and headstock around the nut using a few layers of tape to protect the headstock face and fretboard. Then, slack the strings and pull them to either side of the nut.
Photo 12
Sand a bevel into the backside—the side closest to the headstock—of the nut using P320 and P400 grit Stikit sandpaper on a flat sanding stick. The bevel should start at the back of the nut and come forward about one-third to one-half the thickness of the nut [Photo 12]. Use P320 for most of the sanding and switch to P400 for the last 5 to 10 strokes.
Photo 13
Next, take a fresh Micro-Mesh stick and work through the various grits to buff/round over the bevel you’ve sanded into back of the nut [Photo 13], so it looks and feels good.
Photos 14 (left) & 15 (right)
TUSQ nuts are often tall, and the strings sit deep in the slots. Wound strings require 50 percent of the diameter of the string to sit in the nut slot, with the other 50 percent above the top of the nut surface. The plain strings should be flush with the top of the nut. Take a look at the wrong appearance [Photo 14] and the correct look [Photo 15] for properly seated strings.
How to Sand Your Guitar's Nut
Our luthier shows you how to use a radius block and sand down a nut.
Photo 16
Use a radius block that matches the radius of your fretboard. With P320 and P400 grit Stikit sandpapers, use mild pressure to sand down the top of the nut. Sand a bit and check your progress by setting the strings in the slots and putting a little tension on them. Tuning to pitch isn’t necessary. Use the P320 for most of the sanding, and switch to P400 when you are close to the 50/50 height for the wound strings. The radius block sanding will leave a flat, sharp edge on each side of the TUSQ nut [Photo 16]. To round over the sharp edge, use the sanding block and Micro-Mesh stick.
Use the coarse grit of a Micro-Mesh stick to round over and blend the bevel from the back into the top of the nut. Work through the grit gauges until it’s smooth. There is a fine balance between the bevel at the back of the nut and the top radius of the nut. Go back and forth between the two steps to get a nice, finished look and a nut that functions at optimal levels.
… And Refining the Nut Slots
Nut height is the distance from the top of the first fret to the bottom of the string. A good height on the wound strings is about .020", and for the plain strings about .015". Measuring this gap with a feeler gauge can be tricky because of the fretboard radius. Many repair folks do this by eye and feel, based on experience. It takes some practice. A good check: At pitch, fret the third fret and check for a small gap between the string and the top of the first fret.
How to Widen Your Guitar's Nut Slots
A diamond file can make quick work of deepening and widening nut slots.
Photo 17
The bottom of the string should be sitting on the bottom of the front half of the nut slot [Photo 17]. File down each nut slot to its proper depth using the corresponding nut file. There are diamond nut files on the market in multiple sizes to accommodate many string gauges. Make sure to keep your strokes straight. The standard-toothed files have less sizes and usually require rolling them from side to side to get a well-fit string.
Next, using a proper-sized file, round over the bottom back half of the nut slots down, toward the face of the headstock and away from the strings. This will allow the strings to move freely during tuning or bending, while still having support from the front half of the slot.
How to File D and G String Slots on Guitar
The D and G nut slots require special attention on 3x3-style headstock configurations.
Photo 18
On guitars with 3x3 headstock configurations, the D and G strings need the back half of the slots feathered out away from the center, so the string has a direct path to the tuner post. Using a file that is one size bigger than the string and rolling it side to side on the back of the nut slot will give the string a straight path to the tuner post. Photo 18 is my illustration showing which slots need feathering.
Additionally, use pencil lead to lubricate the slots. Just get in there with the point of a pencil and mark the slot with its graphite. You might also put a drop of Tri-Flow on the front of the string tree. Tri-Flow will run down the string, so take a cotton swab or cloth to clean up any excess. Tri-Flow has Teflon in it, so you don’t need much.
Adjusting String Action
First, find your string height by measuring the string action at the 17th fret on a Fender-style guitar and at the 15th fret on a Gibson-style instrument.On electric guitars, action can range from 3/64" to 3/32", depending on the player’s comfort. My preferences are 1/16" on the treble side and 5/64"on the bass side on both Fender- and Gibson-style guitars measured at the appropriate fret.
How to Adjust Guitar Action
Here’s a look at how our author adjusts the action.
Photo 19
Always loosen the string tension before making action adjustments. This will save wear and tear on the small bridge components. Take either a 6" ruler or a string action gauge and set it on the frets. Measure from the top of the fret to the bottom of the string [Photo 19].
If the action is high, you will lower that string’s saddle or that side of the bridge. If it is low, you will raise it. Make sure the individual saddles are sitting square and upright to the face of the bridge. You do not want them sitting at an angle or leaning over. This will cause buzzing.
Photo 20
The bottom of the strings should match the radius of the fretboard when measured with an understring radius gauge [Photo 20]. Start your adjustment with the outside strings, working toward the center. On Fender-style guitars, set the two outside strings to the height you want and have the middle four strings a bit higher than that. Bring the gauge up from underneath and just touch the two outside strings. Then, bring the strings down a little at a time until the radius matches.
On a Gibson-style Tune-o-matic, the saddles are not individually adjustable. So, if the radius doesn’t match, the saddles will need to be filed. To do this, I recommend using toothed nut files and a rolling side-to-side motion. Do a little work and check your progress. Remember to slack your strings when adjusting the saddle or bridge up or down.
Changing Pickup Height
Photo 21
Finally, let’s take a look at pickup-height adjustment. First, to check pickup height, use the two outside strings again. Press the top wound string on the last fret and measure the distance from the top of the pole piece to the bottom of the string [Photo 21]. This distance can range from 3/64" to 1/8". My preferences are 1/16" on the treble side and 5/64" on the bass side.
Adjusting Guitar Pickup Height
Dave Helmer walks you through the process of adjusting the height of your guitar’s pickups.
On most styles of pickups, there are height adjustment screws on either side of the pickup to raise or lower it. The closer the pickup gets to the strings, the more present string frequencies become. If you get too close, the magnetic pull can affect the string’s vibration and you may hear some strange sounds as you go into the upper register.
On Strats, the neck pickup is regularly set too close, and at the 12th fret and above, the low E and A can sound choked, honky, and not clear. Lowering the neck pickup with a screwdriver usually solves this issue.
Setting Intonation
Photo 22
If you can’t get your guitar accurately in tune, you might need to check its intonation. Adjust all saddles as far back as possible so every string will play flat at the 12th fret. You will adjust the saddles forward, gradually making the octave play sharper until it’s in tune with the open string [Photo 22].
Adjust Your Guitar's Intonation
With a tuner and a screwdriver, Dave Helmer shows you how to adjust your guitar’s intonation.
Depending on your vibrato style, experiment with intonating the plain strings slightly flat. Use your ear and do what sounds good. Sometimes, the plain strings can have perfect intonation, but playing with vibrato can make them sound sharp.
To fine-tune intonation, the individual bridge saddles must be adjustable. Once the intonation is set, recheck the string radius using the understring radius gauge and adjust as needed. The radius can change as the saddles come forward during intonation.
Tri-Flow is great for lubricating saddle parts. Put a small drop on the saddle-height adjustment screws and capillary action will suck it in. Adjust the saddle up and down a few times to coat the threads. Clean up any excess with a cotton swab or cloth. Put a drop or two onto a cotton swab and apply the Tri-Flow to the top of each saddle where the string rests. This will help strings move freely during tuning and after any bends or vibrato.
And that’s it! For a relatively small investment in tools and time, you’re now ready to supercharge your new guitar—and maybe your long-treasured axes, too.
