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
Photo 4
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.
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.
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
With the file positioned vertically, file downward to make the fret end flush with the edge of the fretboard.
Photo 6
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
Then, polish both the sides and the top of the frets.
Photos 8 (top) & 9 (bottom)
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
Photo 10
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.
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.
Tune the guitar to pitch, put a capo on the first fret, and press fret 15 with your left hand.
Photo 11
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.
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.
Photo 12
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.
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, so it looks and feels good.
Photo 13
TUSQ nuts are often tall, and the strings sit deep in the slots.
Photos 14 (left) & 15 (right)
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.
Use a radius block that matches the radius of your fretboard.
Photo 16
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
Photo 17
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.
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
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.
Watch How to File D and G String Slots on Guitar
The D and G nut slots require special attention on 3x3-style headstock configurations.
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
Photo 19
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.
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.
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.
Consider so-called “vintage" or “'50s-style" wiring, in which the tone pot and cap are connected to the middle lug of the volume pot rather than the usual third lug. Given the sheer number of posts the topic has amassed on guitar-geek sites, you'd think it was an earth-shaking option. Yeah, it's a cool mod that I happen to dig, but really, the sonic benefit is modest: just a bit less loss of brightness when you dial down the volume.
These projects aren't like that. Each one drastically alters your guitar's available tones and the ways you access them. They can literally change the way you play.
This article assumes you're familiar with basic soldering techniques. If not, check out a few YouTube soldering tutorials. I don't have to remind you to follow all suggested safety guidelines, do I? (Okay—you're reminded.)
Sometimes the best way to add power to your low tones is to remove a bit of bass.
Mod #1: PTB Tone Control
What it is: A variation on the two-band tone circuit that Leo Fender created late in his career for G&L guitars. It employs two tone pots: One cuts highs like a conventional tone control, while the other filters out lows. PTB stands for “passive treble/bass."
The benefits: This mod is a godsend for players seeking greater control over their distortion sounds, especially with humbuckers. When playing clean, the results are relatively subtle. But when you pour on the gain, even tiny adjustments to your signal's bass content can add clarity, punch, and welcome variation to your crunch tones.
Just ask any savvy stompbox builder or low-tuned 7-string player: Sometimes the best way to add power to your low tones is to remove a bit of bass. That's because the lowest frequencies in your signal disproportionately overdrive your amp and effects. Siphoning off just a bit of bass can add clarity and focus. At extreme settings, the filtering can produce sharp, squawking tones akin to those of a '60s treble booster pedal (not a bad thing). If you've ever grappled with high-gain tones that make your amp fart out, here's your flatulence remedy.
The cost: The original G&L scheme calls for alternate pot values, but the project here uses the 500K pots found in most humbucker guitars, so all you need are wire, solder, and a few capacitors. On a three-knob guitar, you wind up with one master volume control and two master tone controls, but you sacrifice individual volume controls for each pickup.On a four-knob guitar, you still have independent volume controls, but you lose the independent tone controls.
How it sounds:Ex. 1a demonstrates the treble-cut control—nothing surprising here. Ex. 1b features the bass-cut. With a clean tone like this, it's a bit subtle, though you can hear the difference if you focus on the low notes. But Ex. 1c adds a vintage-style germanium Fuzz Face with the gain and volume maxed. With the guitar's tone control wide-open, the signal easily overpowers my vintage Fender brownface—your typical Fuzz Face fart. As I gradually trim bass via the guitar, the tone acquires greater punch and clarity. I remain on the neck pickup throughout—the only thing changing is the guitar's bass pot setting. The extreme-cut settings near the end of the clip may sound harsh in isolation, but they can be perfect in a band context. At the end of the clip I max the bass pot again to underscore how much the tone has changed. It ain't subtle.
How it works — Diagram 1a depicts Leo's original schematic:
The signal from your pickups or pickup selector gets routed to two tone pots. The 500k pot and .022 µF capacitor provide a conventional treble-cut control. Meanwhile, the 1M pot and smaller .0022 µF cap filter out lows. (Pay careful attention to the zeros and decimal points in those cap values!) The treble cut creates its effect in the usual way: by diverting signal to ground. But the bass cut doesn't go to ground at all—the low-filtering cap is inline with your signal. Its output goes to the volume pot (250k in the original). Clever!
Diagram 1b shows my adaptation for three-knob humbucker guitars, using the extant 500k pots:
For visual clarity, I've indicated ground connections with a down-facing triangle. As you probably know, all ground wires must be electronically connected to each other. (One convenient method is to solder all pickup ground wires, the output jack ground, the pickup selector ground, and the bridge's ground wire to the back of the volume pot, and then run a jumper wire to ground the treble control. In conventional wiring, all pots must be grounded, but here, it's not necessary to ground the bass pot.)
Diagram 1c is a version for four-knob guitars, such as traditional Les Pauls. The only difference: On three-knob guitars, the signal usually goes from the pickups to the pickup selector to the pots. But on four-knob guitars, the volume pots are upstream from the pickup selector to permit independent volume control per pickup.
DIY walkthrough: You don't necessarily need to perform the steps in this order—it's just one method.
Photo 1a
Since I have no idea how your guitar is currently wired, I've started with a fresh set of pots. My demo guitar is a three-knob Hamer 20th Anniversary, which has its pickup selector in the control cavity alongside the pots [Photo 1a.]
Photo 1b
In Photo 1b I've completed the ground connections as described above, though I've connected the output jack's ground to the back of the treble pot. The white wire is the pickup selector output, connected here to lug 3 of the treble pot. (Remember: When viewing pots from the back, lugs down, lug 3 is on the left, and lug 1 is on the right.) This wire usually connects to lug 3 of the volume pot, but this circuit routes the signal through the bass pot first.
Photo 1c
In Photo 1c I've added the treble-cut capacitor between lug 2 of the treble pot and ground. I used a .022 µF (also known as a 223). For more cut, try a larger value, such as .033 µF (333) or .047 µF (473). The larger the cap, the greater the cut.
Photo 1d
Photo 1d adds the bass-cut components. Since the output from the pickup selector must feed both tone pots, I've run a wire from lug 3 of the treble pot to lug 3 of the bass pot. I've added a .0015 µF (152) cap between lugs 3 and 2. Here, pot values work in the opposite direction: the smaller the cap, the greater the bass cut. If the .0015 µF sounds too extreme, try stepping up to a .0022 µF (222). I've added a wire to the bass pot's lug 2, which connects to the volume pot's lug 3. Connect the volume pot's lug 2 to the output jack, and you're done.
A reverse-log bass pot? While you can get fine results using your guitar's extant pots, the original G&L circuit calls for a 1M reverse-log pot (the “C" in C1M signifies reverse-log). With a standard audio-taper pot, the effect comes on quickly near the top of the pot's range. With a reverse-log pot, you get a gradual onset of the bass cut that may be easier to fine-tune. The problem is, it's almost impossible to find a C1M pot in a standard 24 mm format. You can get a 16 mm version from stompbox parts suppliers, but it won't work in Les Pauls requiring long pot shafts. After experimenting with various options, I've gone back to a standard 500k pot, because when I reach for that control, I usually want the lows to evaporate quickly.
Mod #2: Nashville Strat
What it is: A Stratocaster version of “Nashville wiring," a trick Telecaster mod popularized by Music City's session cats. Some Tele players add a third pickup (plus a blend knob), expanding the range of combined-pickup tones. The same wiring performs brilliantly in a Strat—without the cost and hassle of installing a third pickup.
The benefits: Access to a stunning array of combined-pickups sounds, including the outer pickups together—a gorgeous color not available from conventional Strat wiring. Not only can you choose between four cool combined sounds, but you can also vary the blend for subtler effects than those of a traditional Strat's 2 and 4 positions.
No matter what position the pickup selector is in, you always have access to the so-called “out of phase" sounds via the blend pot.
The costs: This mod requires a Tele-style 3-position pickup selector in lieu of a Strat's usual 5-position switch. You also sacrifice the sound of the middle pickup alone. The middle knob becomes a pickup blend control, while the third knob serves as a global tone control.
How it sounds: Ex. 2 showcases an assortment of combined-pickup tones not available on a conventional Strat. (The demo guitar is a “parts" Strat with three lipstick-tube pickups. While their character differs from those of traditional Strat pickups, it's a good representation of the range of available tones.) You also have access to the traditional position 1 and 5 tones.
Playing guitars wired this way changed how I view combined-pickup sounds. Whatever position the pickup selector is in, you always have access to the so-called “out of phase" sounds via the blend pot. The blend control becomes something like a camera's aperture setting: In minimum position, sounds are direct and crisp. As you advance the knob, tones become softer, prettier, and more diffuse. I find this to be a more musical and intuitive approach to tone sculpting.
Diagram 2
How it works: The neck and bridge pickup are wired as on a traditional Tele, with the pickup selector's middle setting combining the two pickups. Meanwhile, the middle pickup is routed directly to the output jack, bypassing the tone and volume controls (Diagram 2).
That may seem counterintuitive: Wouldn't you want the tone control to affect both pickups in combined-pickup settings? But it just seems to sound better this way. Rolling back the treble on combined-pickup tones tends to rob them of their cool phase-cancelled character. This way, tones still get darker/warmer when you dial back the treble, yet retain a nice airiness. Try it and see!
DIY walkthrough: In Photo 2a I've replaced the Strat's 5-way pickup selector with a Tele-style 3-way. I've threaded a wire through the two leftmost lugs of the selector's spring side and the two rightmost lugs on the opposite side. Additionally, I've connected the bridge and neck pickups as shown in Diagram 2.
Photo 2b
In Photo 2b I've added all the ground connections. The three pickup ground wires, output ground, and bridge ground are all soldered to the rear of the volume pot, with additional wires grounding the blend and tone pots. (All pots must be grounded in this circuit. It doesn't matter where they connect physically, so long as they connect electronically.)
Photo 2c
You must connect both the volume and blend control outputs to the output jack. In Photo 2c I've removed the jack plate to install a second wire that will connect to lug 2 of the blend pot. (Alternately, you could add a Y-joint inside the main control cavity, reinforcing the connection with heat-shrink tubing.)
Photo 2d
Photo 2d shows the volume pot connections. One output jack wire connects to lug 2, while the pickup selector output (the rightmost lug on the non-spring side, as viewed in this orientation) connects to lug 3. Lug 1 is bent and soldered to the side of the pot for a ground connection, per usual.
Photo 2e
The blend control wiring appears in Photo 2e. The hot wire from the middle pickup connects to lug 3, bypassing the tone and volume controls. The second output jack wire connects to lug 2.
Photo 2f
Photo 2f shows the tone pot wiring. Lug 3 connects to the volume pot's lug 3. Solder one end of the tone-cut capacitor to lug 2, and the other to the back of the pot, grounding it. I've used a .022 µF (223), a standard value, though you can step up to .033 µF (333) or .047 µF (473) for a stronger effect—the larger the cap, the greater the treble cut. If you like the sound of your current tone cap, just reuse it here. And that's it!
Bonus bridge pickup tip: Like many Strat users, I have a love/hate relationship with the traditional bridge pickup. It works great when you want a clear, piercing sound, but tends to be short on mass. Some players remedy this by installing humbuckers or other higher-output pickups in the bridge position. But instead of trying to coax Gibson tones from a Strat bridge pickup, I prefer a Tele-style bridge pickup sized for Strats, such as the excellent Seymour Duncan Twang Banger. With its Tele-style metallic base plate, it provides tough, edgy tones with more mass than traditional Strat pickups—without relinquishing that fine Fender sizzle.
Capacitor Cheat Sheet
Are you confused by capacitor nomenclature? Join the club!
To gain a thorough understanding of how caps work and how they're labeled, Google “capacitor values." In the meantime, here's a handy cheat sheet showing the most common cap values for guitar applications.
The first number in each pair is the value in farads, the unit used to measure capacitance. The “µF" signifies microfarad—a millionth of a farad. People often substitute “uF" for “µF" to avoid the hassle of using a Greek letter. It's also sometimes written as “MFD."
The second number in each pair is the shorthand way of indicating these values, and that's usually the number you find on the caps themselves.
The values appear in ascending order. The ones highlighted in green are typical values for conventional treble-cut tone controls. The ones in red are good starting values for the bass-cut controls in these projects. If a particular value doesn't work for you, just step up or down in value till you hear what you like.
- .0001 µF (101)
- .00015 µF (151)
- .00022 µF (221)
- .00033 µF (331)
- .00047 µF (471)
- .00068 µF (681)
- .001 µF (102)
- .0015 µF (152)
- .0022 µF (222)
- .0033 µF (332)
- .0047 µF (472)
- .0068 µF (682)
- .01 µF (103)
- .015 µF (153)
- .022 µF (223)
- .033 µF (333)
- .047 µF (473)
- .068 µF (683)
- .1 µF (104)
Capacitor hacks. If you find yourself lacking the perfect cap value, remember that you can wire together two caps in parallel, as shown in Photo 1e.
Mod #3: Varitone Variation
What it is: The original Varitone, which appeared in such vintage Gibsons as the ES-345 and ES-355, is a controversial circuit. In lieu of standard treble-cut caps and pots, it employs a rotary switch, with each position routed through a different-sized capacitor. It also calls for an inductor, which creates a series of notch filters. (In other words, the circuit doesn't remove all signal above a certain frequency, but only a certain amount above and below that frequency.)
While the Varitone has its fans, it was never very popular. Detractors argue that it sucks tone, and its settings are too thin and “quacky" for many players. But even if you don't dig the original Varitone sounds, you can use its general concept to great effect. (For example, if you omit the inductor, you lose a bit of the peaky resonance that alienates some players.)
You might want to deploy your pots for something other than the traditional uses—controlling onboard effects, for example.
The benefits: Multiple capacitor schemes can provide instant access to a wide range of favorite settings, plus others not available from a conventional tone control. Instead of fiddling with a pot, you can leap to the desired tone with the flick of a switch.
The cost: When you replace a tone pot with a tone switch, you lose access to settings that “fall between the cracks" of the switch positions. You also need various switches and caps, depending on how you configure the mod.
How it sounds: I wired up a multi-cap, two-switch tone circuit in a “parts" Jazzmaster with P-90s and flatwound strings. Ex. 3a demonstrates my three treble-switch settings. You hear my three bass-cut settings in Ex. 3b. As with the PTB mod, the variations can be subtle with clean tones. But when I add a custom germanium booster in Ex. 3c, everything gets much more dramatic. The entire clip is performed on the bridge pickup—the only things changing are the tone switch settings.
Multi-capacitor switches let you choose your own set of cutoff frequencies, but once a capacitor is engaged, it's engaged all the way. So instead of cutting varying amounts of signal at a fixed frequency, you cut fixed amounts of signal at varying frequencies.
Diagram 3a
Diagram 3a shows the basic idea. The center lug of the rotary switch connects to lug 3 of your volume pot, like a conventional tone control. You weave capacitors of escalating value through the lugs lining the pot's perimeter, so that when you move the switch, a new cap is engaged. The other terminals of the caps go to ground—usually by bundling them together, wrapping them in heat-shrink tubing, and soldering the assembly to a ground point. (Most rotary switches let you specify the number of active positions via a notched washer on the pot's shaft.)
Photo 3a
This is a cool mod, but there's one good reason not to bother: Someone beat us to it. This is precisely how Stellartone's ToneStyler replacement tone pots work. They're fine products, and if you can afford the cost (models start at $75 street), I recommend them. Photo 3a shows my homemade part alongside a ToneStyler—which would you rather put in your guitar? (Plus, I hate the stiff, clunky feel of the commonly available rotary switches.)
Instead, let's look at an approach that uses mini-switches rather than a big rotary switch. These limit you to three settings per switch, as opposed to as many as a dozen from a rotary switch. But there are at least two good reasons to go this route: It's easy to install mini-switches on almost any guitar, while adding pots can be problematic. And there are times when you might want to deploy your pots for something other than the traditional uses—controlling onboard effects, for example. (Which, by the way, is the subject of an upcoming Premier Guitar article.)
Diagram 3b
There are many types of mini-switches, but this project calls for the on/on/on DPDT variety, which have two rows of solder lugs and three switch positions. Diagram 3b shows how they work—and how to configure them as treble-cut and bass-cut controls.
A 3-position treble-cut switch. For a treble-cut switch, connect the input to the left-center lug, and a ground wire to the right-center one, as shown in Photo 3b.
Photo 3c
With the switch in the down position, the signal gets routed through whatever you connect to the top two lugs. In Photo 3c I've threaded the first of two treble-cut caps—a .022 µF (223)—through the top lugs.
Photo 3d adds a second tone cap—a .0033 µF (332)—between the lower-left lug and the upper-right one. This is engaged when the switch is in the middle position. There's nothing between the two lower lugs—when the switch is in the up position, no tone cap is active, and your tone is wide-open.
My cap values are customized for the way I tend to use treble-cut controls: either to take off a bit of edge, or to get very dark. Configured this way, I get an open sound when the switch is down. In the middle position, there's a slight treble cut from the relatively small .0033 µF cap. And in the up position, I get a much darker tone via the larger .022 µF cap. You can vary these values to taste—just remember that larger caps cut more treble.
Photo 3e
A 3-position bass-cut switch. The wiring is similar for a bass-cut switch, but with one key difference: While the treble-cut routes signal to ground, a bass-cut must be inserted within the signal flow, just as in the PTB project above. The signal comes in via the left-middle lug, and exits via the right-middle one, as shown in Photo 3e. Also, I've added a jumper wire between the two lower lugs, so when the switch is in the up position, signal is routed through the switch without encountering a capacitor. (To reverse the orientation, just flip the switch 180 degrees.)
Photo 3f
In Photo 3f, I've added two capacitors, as in the treble-cut circuit. I used a .0033 µF (332) for a slight bass cut in the middle position, and a .0015 µF (152) for a more extreme cut. Choose your own cap values, bearing in mind that the smaller the cap value, the greater the bass cut.
Diagram 3c
Finally, Diagram 3c shows my two-switch/six-setting tone control as heard in Ex. 3c. With the values I used, the result is similar to the PTB mod above, but with two added advantages: I can toggle quickly to the exact tone I desire. And by drilling two small holes in my pickguard to accommodate the mini-switches, I freed up my former tone pot for another task: controlling an onboard booster.
Mods à la mode. I urge adventurous solder jockeys to try all three mods. They're easily reversible (except for pickguard drill holes), and even if you don't dig the results, I'd be surprised if the process didn't suggest alternate ideas more to your taste. You'll learn volumes about guitar electronics as you uncover your ultimate mod.
[Updated 11/30/21]
However, when I’m building a guitar, there’s a myriad of small adjustments I can make to steer the instrument on a desired trajectory. These micro mods are interactive with each other and, depending upon the combination, offer a wide variety of sonic outcomes. But these little mods can also be applied to existing guitars—your guitars—in any number of permutations and to great affect. Let’s take a look at five mods that are easy enough for most players to try.
1. Foaming Pickup Cavities
The first and easiest adjustment that most electric guitars can benefit from is stuffing soft foam into the cavity behind the pickups in order to stop microphonic squealing. The first time I used this was when I was repairing a Gibson Firebird for Johnny Winter—the foam stopped the pickup’s back plate from vibrating like a microphone diaphragm. I have since learned that reducing the space (the cubic volume) behind a pickup modifies its sound at higher sound levels. Discovering this resonating-chamber effect has altered my approach to routing a body for pickups on new guitars, too.
It’s easy to remove your pickup or pickguard and slide some foam rubber behind the unit. Start with soft foam first, and then increase the density to find the difference you like. Conveniently, the gray foam used in aftermarket pickup packaging makes great damping material: It’s soft enough that you can double it up (see Fig. 1 and Fig. 2) to create more pressure on the pickup’s back plate, too. This is a relatively no-frills mod that requires minimal materials and tools.
2. Pickup Magnet Tricks
As we all know, sometimes a pickup isn’t a perfect match for a guitar. I always approach pickup selection like a vocalist would choose a microphone—finding the one that best brings out the guitar’s character rather than attempting to change that innate character with a new pickup.
With this in mind, try swapping your existing pickups’ magnets instead of replacing the whole thing. Magnet type and strength are big contributors to a pickup’s tonality, so it stands to reason that tweaking them will affect your sound.
Swapping magnets is easiest to do with humbuckers. In fact, it can actually be done without completely disassembling the pickup—and sometimes without even unsoldering it.
The first step is to determine what’s in your pickup already. The most common magnets for humbuckers are (roughly in order of strength): alnico 2, alnico 4, alnico 5, and then various types of ceramic magnets. In simple terms, the stronger the magnet, the greater the potential output. But you can’t just look at magnetic strength alone, because stronger magnets also affect the string’s ability to sustain.
By moving up or down one level, in terms of magnetic strength, you can usually add or subtract a little edge from a pickup. If your guitar is too tangy, moving down one pickup level (e.g., from alnico 4 to alnico 2) may smooth it out. If you want to add bite, go with a slightly stronger magnet—like, alnico 5 to a ceramic magnet. The good part is that magnets are both easy to find and inexpensive in comparison to buying a whole new pickup.
Here’s how to swap magnets in a humbucker:
1. Before you begin, determine the magnet’s polarity orientation (north/south). You can use a simple magnetic compass to do this (Fig. 3).
2. Desolder the main leads and remove the pickup from your guitar.
3. Remove the protective outer tape (Fig. 4). This gives you a clear view of the internal parts. (Note: Be careful not to pull out the hookup wires underneath.) You should be able to see the magnet in the center, underneath the two coils.
4. Loosen the four small coil-mount screws on the underside of the pickup (Fig. 5).
5. Raise each of the adjustable pole pieces about four turns to release the coil from the back plate (Fig. 6).
6. Gently pry the coils from the plate to provide a little gap (Fig. 7).
7. Place a screwdriver in the gap at one end of the pickup and slowly tap the magnet out (Fig. 8). Once enough of the magnet is exposed outside the housing, you’ll be able to pull the magnet out with your fingers. (Note: If your pickup is wax-potted, you may encounter some initial resistance as the wax breaks free.)
8. Slide in your new magnet, being careful to match the same magnetic orientation you observed in step 1 (Fig. 9).
9. Return the adjustable pole pieces to their prior position, replace the coil-mount screws and tape, and re-install the pickup in your guitar.
3. Modern vs. Vintage Wiring
Another relatively drastic but easy and cheap way to hot-rod your guitar’s sound with its current components is to alter how and where its volume and tone pots are connected to each other. The difference can be subtle—and it’s more a matter of preference than what’s “correct”—but it can make the difference between a guitar that is just OK and one that really is a joy to play.
With this mod, what you’re essentially doing is changing the way the tone and volume control interact, based upon how they “load” each other. I’ve mocked up a control setup here showing one volume and the corresponding tone control.
Fig. 10 Vintage wiring—which has pickups wired to the volume pot alone, and the tone control’s capacitor being attached to the output—yields minimal high-end roll-off when you turn the volume down. Fig. 11 Modern pickup circuits often have the tone control affecting the pickup’s tone before it gets to the volume knob, yielding a decrease in treble response as volume is reduced.
In the vintage setup, the pickup is wired to the pot lug alone, with the tone control capacitor being attached to the output side. This tends to allow the volume to be rolled off without losing too much high end. This is great for those who play clean rhythm by just lowering their guitar volume as opposed to switching amp channels or turning off a boost pedal. It’s old-school, and it works. The downside is that the tone control sometimes has to be rotated a bit more before its effects are heard.
In our so-called modern configuration, the tone cap is attached to the pickup before the volume pot. This presents the volume control with a totally different signal, resulting in a more colored sound as you reduce the volume. This can be useful if you like to turn up the guitar to cut through more. For me, the downside is the way it makes the tone control a bit of a hair-trigger affair. If you’re the type who avoids the tone control, this won’t be a factor for you.
If you have two sets of volume and tone controls (e.g., on a standard Les Paul), you may or may not decide to wire them differently, which can potentially open the door to even more tonal variations.
4. Add Steely Twang to Your Strat
There are times when a single-coil just doesn’t have enough twang. I’ve encountered Strat neck pickups that are just too wooly to provide me with that saucy, SRV/Hendrix-style rhythm juice. Or, sometimes an anemic bridge pickup just needs an extra dose of snap to push it into Tele-like territory. If so, this simple mod could be just what you’re looking for.
When Leo and the boys at the big “F” ranch developed the Tele, they put a big slab of steel under the bridge-pickup coil. This reflected the magnetic field up and toward the strings. In the words of Seymour Duncan’s Evan Skopp, this gives it more “crack”—which, if you’re addicted to twang, is a good thing. The better news is that you can attach a plate (sometimes called an elevator plate, because of how it elevates the magnetic field toward the strings) to any single coil whose pole-piece magnets are exposed at the back.
To do so, purchase a small piece of .047"(18-gauge) sheet steel from your local hardware store. Then:
1. Trim it to a manageable size and shape—about the same dimension as the pickup bobbin (Fig. 12). Then trim it so that it fits within the perimeter of the base plate without touching the lead wire contacts (Fig. 13). 2. Using a small piece of thin, double-sided tape, fit the plate over the bottom of the pickup, and then secure it with dabs of adhesive (Fig. 14). I prefer hot glue, because it’s easy to remove, but you can use epoxy or super glue, too.
This mod works great for Strat-type pickups or aftermarket Tele-style reproduction pickups that don’t already have a plate. Some pickup companies make P-90s that don’t have a metal base plate, and these can be twang-ified in this way, too. The best part is that, if you don’t like the sound, you can just peel the plate off and be right back where you started.
5. Fine-Tuning Your Tuners
This mod is a little different—and definitely not as affordable as the ones we’ve been talking about up to this point. When players think about modifications that involve tuning machines, the subject revolves around tuning stability. That’s all well and good, but I’ve rarely encountered a quality machine that slips—because the mechanical torque required to turn the tuner’s capstan is pretty stout. Problems of pitch are usually more related to capstan wobble or a bad nut-slotting job.
However, there’s another aspect of machine-head selection that I contemplate when building a custom guitar: weight. But this is more about sustain and tone than a question of neck-heaviness.
I’ve written in previous issues of Premier Guitar about how the size and shape of a guitar’s headstock affect its sustain and tone. Clearly, the mass of the tuning machines is a factor in this, as well. Having overseen the building of tens of thousands of custom guitars over the course of my career has given me cause to consider machine-head weight as a fine-tuning tool in and of itself. This kind of mod is more complex than the others I’ve presented here because it is harder to predict, and obviously more costly to dabble in because it involves replacing the existing tuners. Nevertheless, I put it out there for those of you who are willing to go to the limit of sanity in the search for a responsive instrument.
This mod revolves around the concept that adding mass to the headstock lowers its resonant frequency, while reducing mass will raise that frequency. The theory at work here is that vibration is absorbed or reflected back into the strings and body based upon this frequency. Depending upon the harmonic makeup of your particular instrument, changing this can enhance or degrade sustain and accentuate or attenuate certain harmonics. All of this is dependent not only on your guitar’s construction, but also on how large your headstock is to begin with. If all of this seems a bit hazy, that’s because it is. I don’t have a handy-dandy answer like “more mass equals more sustain” because it isn’t always true. Suffice it to say that you can make a difference in a guitar’s character by following this path. I usually go through this exercise with my builds because I have the luxury of time and the resources at hand. It’s like fine tuning a race car’s suspension settings to your liking.
Most of the better machine heads on the market these days use a standard .375" headstock hole, so swapping tuners isn’t that hard to do. The problem comes with the mounting at the rear of the peghead. Luckily, if you use the type that screw down from the front side with a nut and washer, you can swap and test before you drill additional mounting-screw holes.
To illustrate the potential variances in weight that one can expect with different tuners, I rounded up three of the most common choices and threw them on my shop scale. You can weigh your current machines to compare. Be sure to weigh all the hardware— screws, nuts, and washers—because it all comes into play. (All weights are in grams.)
The lightest of the bunch are minimalist Sperzel tuners, which look pretty sci-fi. They clocked in at 138 grams (Fig. 15). Well-made and beautifully finished, the Sperzels use a pin-mount on the back instead of wood screws—further reducing weight. This can be a game-changer if you have a substantial headstock.
Next up are the wonderful vintage Kluson reproductions by TonePros (Fig. 16). These are some of my favorites, and they weigh in at a moderate 186 grams with all hardware included. For many of my builds, the characteristics of these tuners are ideal. I enjoy the modern engineering these tuners hide within their vintage-styled exteriors, and the weight is almost perfect.
Unabashedly brute class, with typical German overbuilding, the Schallers shown here are the Incredible Hulk of the bunch (Fig. 17). At a hefty 272 grams, they have the might to get noticed when you fasten them to your axe. If you have a guitar with a tiny headstock, you’ll hear and feel a difference with the Schallers. Whether or not you like the change is subjective, and it depends on the makeup of the rest of your guitar.
Sweat the Small Stuff
As we’ve shown here, a lot of relatively small—and inexpensive (many are practically free)—tweaks can hot-rod your tone and maneuver it to an array of differing ports of call. In some ways, it’s like tossing a handful of dice instead of just two—because the way small tweaks interact can lead to exponential changes in sound. For that reason, my advice is to take it slow and only make a single change at a time to understand what it delivers. Besides, it’s more fun (and less stressful) that way, anyway!
[Updated 12/30/21]