Replacing a Bridge P-90 Pickup With a Humbucker in Epiphone Les Paul Special — Routing 101 | DIY
I’ll demonstrate by converting part of a new guitar into sawdust and noise, then transforming the instrument by installing a totally new pickup in the bridge position—so we can retain the natural flavor of the P-90 in the neck, but goose up the bridge position with a humbucker. And to make things even easier, there is a video of me doing this mod online at premierguitar.com, which I highly recommend watching. In it, I explain every step in great detail.
The guitar is a brand-new Epiphone Les Paul Special finished in glossy TV yellow—in my opinion, the best furniture finish ever commandeered for broadcast purposes—loaded with two P-90 pickups, black plastics, and chrome hardware. The pickup going into this guitar is a Parsons Street Humbucker by StewMac. Designed to emulate a popular variation of the traditional PAF-style humbucker, this medium-output pickup should retain plenty of treble clarity. It will mount to the guitar with a classic black humbucker mounting ring.
What You’ll Need for This Mod
Besides a guitar, a small bandsaw for cutting the pickguard, and painter’s tape, you can pick up everything you need for this modification project online at StewMac.com.
• Bosch Colt 1 HP Variable-Speed Palm Router
• Bosch Plunge Base for Palm Router
• Parsons Street Humbucker
• Fisch Wave Cutter Bit 5/8"
• Amana Tool Carbide Tipper Router Bit 1/4"
• Humbucker Pickup Routing Template
This is what our project guitar looked like before it hit the workbench.
Since we are on the topic of pickups, I’d like to note that the acronym PAF does not define a specific sound or a strict recipe for pickup making. It is simply a description of a design—Patent Applied For. Both P-90s and PAF-style humbuckers actually have a lot in common. If you examine their construction, it seems the goal for PAFs wasn’t necessarily a different-sounding pickup, just one that didn’t hum like its single-coil predecessors.
The OEM pickups in this Epiphone Les Paul Special are quick-connect, which makes for easy disassembling, but will require trimming the connectors and soldering as part of the humbucker’s installation.
As a result, a lot of the early Gibson ’buckers and P-90s have comparable output and not entirely dissimilar frequency response, depending on their magnets and how the coils were wound. These factors varied quite a bit for the first few years of production and produced some very different sounding pickups.
But, back to the bench, focusing on the task at hand.
Our author holds a StewMac humbucker-sized routing template over the pickup to be replaced.
This guitar is a good candidate for this kind of pickup swap for a few reasons: One, we only have to modify an existing pickup cavity; two, a medium-output bridge humbucker such as our Parsons Street should complement the sound of the neck P-90 nicely; and three, while the modification will be obvious, this new pickup will also complement the classic looks of the guitar.
The pickups are mounted to the body via two easy-to-remove screws.
You may be here looking for inspiration as much as information—thinking about trying this modification yourself, but still not sure. Although it’s ultimately your decision, I can at least equip you with some arguments for and against.
Try the mod if:
• You are curious about how different pickups sound and you recognize the benefit of using the same guitar as a control in your experiment.
• You love everything about your guitar, but want a little more punch from the bridge pickup. This is common with single-coil pickers, Telecaster aficionados excluded.
• You might deem the guitar cooler this way. After all, it’s an uncommon but highly effective treatment for this model—which could make you want to play it more.
Don’t try this mod if:
• You have a more valuable, historic, or rare instrument.
• The resale value of the guitar matters to you.
• It’s not your guitar (LOL).
• Safety and preparation are not priorities.
Don’t Fear the Router
The part of this modification that scares most people off is working with a router. It’s an intimidating device and fear of it is understandable, considering what it can do to a guitar, or fingers, but learning about how it works and how to use it should, hopefully, alleviate your fear.
A router is a powered chisel that does what a standard chisel can do, good or bad … only faster. Positive or negative results depend entirely on the operator, just like any hand tool. And good results come from developing good technique and practice, which is one of the skills this mod aims at developing.
There is a wealth of information available about technique and a limit to the length of this article, so I’m only going to focus on a few basic tips that will help you get started safely:
• Only power the router on or off when the bit is able to turn freely, not in contact with any material.
• Do not move the router while the bit is accelerating or decelerating.
• Multiple shallow cuts are better than one deep cut.
• Pay attention to the router bit’s direction of rotation when planning the direction of the cut.
• Use PPE—at the very least, safety glasses.
Now we can get started with the project. However, there are several things to do before we can begin making sawdust and noise.
If you’re just too excited about firing up the router and can’t wait, I understand, but please read through these steps first. Afterwards, feel free to practice some small shallow cuts on the edges of scrap wood before jumping into the project, using large enough pieces that can be secured to your work surface. This will give you a good idea of how the router feels and sounds when making a cut.
Step 1: First, all electronics and hardware should be removed from the guitar, to make sure we have plenty of room to operate the router without any obstacles. Take photos and draw diagrams now if you’re unfamiliar with guitar wiring, since you will probably have to disconnect the pickups and switch wires, and will definitely be connecting the new pickup. [Marshall provides instructions on this step in the video companion to this story on premierguitar.com, and StewMac has detailed wiring instructions on its website.]
Note that on this guitar, although the pickup selector switch is not in the way, I suggest removing the switch to keep the wires away from the router bit.
Step 2: Next, make sure the new pickup fits inside the template for the new pickup cavity. Make sure you have enough clearance to move the pickup through the template. It shouldn’t catch or rub on any part of the template.
Line up the template on the guitar body to determine where the new cavity will be. There are several techniques you could use here. Some might locate and mark the guitar’s center line, then line up the template that way, but since we are modifying an existing cavity we know is more or less centered, I suggest using that cavity as a guide and eyeballing it. Carefully.
Since the StewMac template has a center line and other measures on its face, it’s easy to position over the cavity for the OEM pickup and decide which of its zones need routing.
Step 3: Now that you know where the template goes, attach the template to the guitar. I prefer using rolled up painter’s tape on the bottom side of the template because it holds fairly well (as long as you don’t use too much force with the router), it’s easy to remove, and relatively safe for modern finishes. Stronger double-sided adhesives work well but run the risk of damaging either the guitar or the template on removal.
After taping the template in place, Marshall uses the router bit to trace the path he’ll use, and to gauge the depth of the pickup cavity versus the location of the bit’s bearing.
Step 4: The template determines the shape of the new cavity, but the router itself determines the depth of the cut. Start by setting the depth so that the tip of the router bit is just barely touching the bottom of the cavity when the router is sitting on the template. Once the cut is made, we can double-check to make sure this depth works.
With the template secured and the depth of cut adjusted, I suggest trying a “dry run” of the cut to make sure the router moves freely around the template. Keep in mind the bit’s direction of rotation and plan moves that allow the bit to cut into the wood—but don’t do it yet. Just outline your moves. Make sure that the bearing on top of the router bit can freely follow the template, too. Setting the depth too shallow risks cutting your template, ruining both it and your guitar.
This seems like an excessive amount of preparation, but trust me, an hour of planning can prevent a minute-long job from destroying your guitar.
It’s almost time for the fun part. Don’t turn the router on yet. Put on your safety glasses and consider using ear protection if you are sensitive to high-pitched, loud sounds. This would also be a good time to make sure you have a shop vacuum handy, as you are about to make quite a mess.
Step 5: Now, it’s time to actually make the cut. Tilt the router slightly so that the bit is completely free before turning the router on. Keep in mind that the router should not be moved while the bit is accelerating or decelerating, so don’t make any cuts until the router is at full speed.
Once it’s at full speed, make the cut as practiced earlier. Take several shallow passes instead of trying to remove all the wood at once. There’s no need to force the router, you will hear and feel when the bit is cutting. Too much force may cause your template to move and ruin your cut, wreck the router bit, or potentially hurt you. And since the router spins the bit in a specific direction, be sure the cutting edge of the router is digging into the wood and that you move the router in the direction that puts the blade edge of the bit forward.
Now, you can turn the router off, but remember not to move it until the bit has completely stopped rotating. Check that the template has not been damaged, that the cut matches the template, and the pickup fits neatly inside.
The sawdust flies as Marshall uses the router to slowly make gentle, shallow cuts, eventually reaching the cavity size required for the Parsons Street Humbucker.
Step 6: With this specific type of pickup, it turns out that we do need to make two slightly deeper cuts to accommodate the mounting screws and “ears” of the pickup base. You can do this by setting the bit to cut just a little deeper—in our case about 3/16" deeper—and cut only the areas around the pickup mounting screws. You could also do this with a hand drill or a drill press and a large spiral or Forstner bit, but I prefer the cleaner results from the router.
Checking the final cut to be sure there are no issues like snags or protrusions that would interfere with the fit of the pickup.
Step 7: Now, the new bridge pickup should fit. Test it by mounting the pickup in its ring and placing this assembly on the guitar. The mounting ring should sit on top of the guitar without having to force it down. If everything fits, go ahead and rewire and reassemble the guitar, then set it up to your liking. [We have a video at premierguitar.com called DIY: Easy 4-Step Guitar Setup.]
After placing the ring around the pickup, Marshall drops the humbucker and ring into place to test the fit. (As it turned out, a little bit of additional routing was required for the bottom of the cavity, to provide space for the humbucker’s left-side dog-ear mount.)
Step 8: On this Les Paul Special, since I’ve replaced the bridge P-90 with a bigger and more squared-off pickup mounting ring, the pickguard will have to be modified slightly to fit. I did this by tracing the pickguard onto a piece of paper, taping the tracing to the guitar, then marking the outline of the new pickup mounting ring. Now, I can use the tracing as a template and cut away the parts of the pickguard that I don’t need. I used a small bandsaw blade to cut away most of the material and slowly fine-tuned the edges with files and a small scraper until it fit.
Here’s the paper template Marshall used to trace the new pickguard configuration required to accommodate the Parsons Street Humbucker. He then placed it atop the actual pickguard to make the cut.
I like to start with my bridge pickup very close to the strings, somewhere around 3/32" away from the treble strings and balancing the bass side of the pickup by ear. After that, I like to set the height of the neck pickup just by comparing the sound of each pickup, again, making sure that the output of each pickup is balanced from the bass side to the treble side.
To my ears, the humbucker we used in this guitar works very well paired with the stock P-90 in the neck position. It’s a medium output pickup, so it does have a bit more punch than the P-90 but doesn’t overpower it. Higher output humbuckers can roll off a bit of treble, depending on how they’re made, but this pickup has plenty of brightness for me. Both pickups together have abundant chime and sparkle. I really like this sound!
The proof is in the playing: Marshall tries out the Epiphone Les Paul Special’s new, combined humbucker-and-P-90 sound.
And on top of all that, I think this guitar looks really cool now as well. To me, that’s worth an afternoon’s work.
Learning to use a router is a great introduction to serious guitar modifications. It can be intimidating, but once you learn the basics, it opens up so many possibilities for modifications and repairs. Embrace the router!
Shop DIY tools and Supplies for your next guitar project: https://stewmac.sjv.io/qnPnag
Fig. 1. Changes in temperature and humidity can cause checking in traditional nitrocellulose lacquer finishes.
Over time, sweat, dirt, and oils build up on the guitar's finish and slowly break it down. This causes the finish to develop a hazy film and become discolored. In addition, if your sweat has a high acid content (low PH balance), it can actually cause the finish to deteriorate, especially where you rest your arm. Sweat contains water, acids, salt, and several minerals that are corrosive to finishes and hardware. When you add in environmental issues, such as dust and pollen, it's no wonder our guitars get so filthy.
A little background. There are many different types of finishes used on stringed instruments. Vintage instruments typically sport nitrocellulose lacquer—a thin, hard finish that lets the wood resonate well. But nitro is also prone to checking and cracking over time (Fig. 1), especially when the instrument is exposed to sudden temperature and humidity changes. To combat this, many modern guitar builders and manufacturers cover their instruments with finishes that are more impervious to environmental conditions. These include urethane, acrylic, polyester, and epoxy formulations. In some cases, the switch from nitro is a way to save production costs, but builders can also be motivated by a desire to spray materials that are less harmful to the planet and workers. For example, in recent years there has been a trend toward UV-cured and water-based finishes, both of which reduce chemicals released into the atmosphere during production.
Fig. 2. A gloss finish (left) looks shiny and usually feels smooth and glass-like to the touch. Fig. 3. A satin finish (right) has a softer, less reflective sheen, allowing you to often feel the wood grain.
Modern finishes come in two styles: gloss and satin. Gloss finishes are shiny and have a glass-like look (Fig. 2), while satin finishes have a softer, hazy sheen (Fig. 3) and sometimes can actually feel "unfinished."
Cleaners and polishes. No matter what kind of finish is on your instrument, it's a good idea to keep it clean to prolong its life. There are hundreds of products on the market that claim to be the best for cleaning and polishing an instrument. The truth is many of them will cause the finish to slowly deteriorate. These cleaners contain petroleum products and solvents that can damage a nitrocellulose finish, and some polishes contain abrasives that will remove a vintage instrument's natural patina. The best guitar care products won't leave behind residue and do not contain solvents or petroleum products.
There's a debate about whether polishing a guitar is more harmful than helpful. When you polish a guitar, it creates a seal or coating that's intended to protect the finish. However, I've found that the outcome is more cosmetic than functional, and many finishes don't benefit from waxing or polishing. Polishes and waxes build up over time and can eventually dampen the sound of your guitar—almost like wrapping it in a bed sheet.
But that's not all: If your guitar has finish checking, polish will build up in the hairline cracks, and this can discolor the wood underneath or even cause the finish to flake off. Based on experience, I believe cleaning your guitar is more beneficial than polishing or waxing it. Polishing will make your guitar look better, but really doesn't benefit the finish other than making it shiny. If you feel compelled to polish your instrument, look for products that contain pure carnauba wax—it's the safest for your guitar.
Fig. 4. Professor Green's Instrument Polish (left) is a water-based "guitar soap" that cleans effectively and leaves no residue. Fig. 5. Planet Waves Hydrate (center) is formulated to condition and clean unfinished fretboards. Fig. 6. Naphtha (right)—the main ingredient in lighter fluid—is safe and effective for cleaning most finishes and hardware. However, it's toxic and flammable, so you must carefully follow the manufacturer's directions.
Three products I've found to be both safe and effective for cleaning a guitar's finish are Professor Green's Instrument Polish (Fig. 4), Planet Waves Hydrate (Fig. 5), and naphtha (Fig. 6). Though each is radically different, they can all be used with a damp cloth.
Here's the breakdown: Professor Green's Instrument Polish is a natural, water-based liquid cleaner with no harsh chemicals. I'd classify it as "guitar soap" rather than a modern polish. It does an excellent job cleaning dirt, oil, sweat, and oxidation. Being water based, it's very easy to clean up without leaving any residue.
Planet Waves Hydrate fretboard conditioner is a paraffinic hydrocarbon-based liquid. Effective for removing dirt and oils from most any finish and unfinished fretboards, it's non-toxic and non-flammable.
Which is not the case for naphtha—essentially lighter fluid. It is a gentle and high-flash solvent that's safe for most finishes. (Naphtha-saturated Q-tips do a great job cleaning rusty saddles and bridge hardware.) However, naphtha fumes and liquid are toxic to humans, so if you use it, I recommend wearing a mask and gloves. It's highly flammable, so avoid open flames!
No matter what brand or type of cleaner you choose, always avoid those that contain silicone, heavy waxes, lacquer thinner, bleach, etc. Household furniture polish and all-purpose cleaners—such as Pine Sol, Windex, and 409—will also damage your finish. The only household product that's safe to use to clean your guitar is white distilled vinegar. It will clean the finish, but do you really want a guitar that smells like a pickle?
Fig. 7. A damp paper towel (left) or microfiber cloth works well to clean a guitar's finish. Fig. 8. Use a Q-tip (right) to clean hard-to-reach nooks and crannies.
Cleaning the finish. When cleaning your guitar, I recommend using a damp paper towel or microfiber cloth. Spray or dab a little cleaner on the towel and gently wipe away the dirt (Fig. 7). Avoid saturating your guitar with water. It's okay to use a lightly damp cloth, but don't waterlog it. Use a Q-tip for those hard-to-reach areas (Fig. 8). Once the guitar is clean, go over it once more with a clean, damp cloth. That's it—quick and simple.
Polishing a gloss finish. If there are a lot of light scratches and swirl marks in a gloss finish, you need to decide if it's worth buffing them out. This really depends on how old the guitar is and what type of finish it has. If it's a fairly new guitar, it's okay to use a gentle buffing compound, such as Meguiar's M85 Mirror Glaze or Planet Waves Restore (Fig. 9), with a microfiber cloth to remove these marks. Keep in mind that every time you use any compound to buff out a finish, you are removing finish, so use polish sparingly and with great discretion.
Fig. 9. Buffing compounds can remove swirl marks and light scratches in a gloss finish,
but you should never buff or polish a satin finish.
Please note: If your guitar has a satin finish, never buff or polish it. Cleaning is fine, but buffing and polishing a satin finish will make it look blotchy.
Another cautionary note: If you have a vintage instrument with a nitro finish, be aware that as a normal part of the aging process, most nitro finishes will change color and develop a sheen or patina. When cleaning a vintage guitar, go easy—you simply want to remove the dirt, oils, and sweat. The underlying patina adds to the instrument's value, and removing it to make the finish shiny and pretty will devalue your guitar.
[Updated 7/25/21]