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
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What you’ll need for this project:
Parts and Supplies
- Three Seymour Duncan JB Jr. pickups
- Pure Tone Multi-Contact Output Jack
- .022MFD orange drop capacitor
- Two 500k CTS potentiometers
- One push-pull pot DPDT on/on switch assembly
- 60/40 rosin core solder
- 22 AWG non-shielded PVC-insulated circuit wire
- Heat shrink tubing
- Small zip ties
- Guitar string set
Tools
- Soldering Station
- Small clippers
- Small round-nosed pliers
- Phillips screwdriver
- 1/2" nut driver
- Strip of painter's or masking tape
- A small jar with a lid
For example, I’m going to show you how a hardtail Squier Bullet Strat, which you can pick up for less than $200 street, can be transformed into a more versatile tone machine by non-invasively replacing its stock single-coil pickups with humbuckers and installing a push-pull pot for coil-splitting the neck and the bridge pickups—where many of the sweet sounds live. While I’m at it, I’ll explain how to install a more durable and efficient jack. Even a beginner can conceivably do all of this over a weekend, and the result will be a very playable guitar with a wide selection of sounds that you can enjoy for many years.
One thing I’ll ask you to do first is brush up on your soldering skills. Unless you’re already on top of those, you should check out “Soldering 101: A Step-by-Step Guide” at premierguitar.com. If you don’t have a good soldering iron—one that’s got controllable temperature settings and speedy thermal recovery—you should get one. I prefer to use a Hakko Soldering Station ($115 street) with digital readouts, and keep the temperature set at 750 degrees Fahrenheit. Here it is, in Photo 1.
Photo 1
Keep in mind that any iron you use should be at least 40 to 60 watts or it will not get the solder or metal points hot enough. (Twenty-five-watt irons are common, but don’t use them for this job. They are for delicate circuit-board soldering and not point-to-point work.)
I also recommend Kester 60/40 rosin core solder, which is 60 percent tin and 40 percent lead, in .062" thickness. It’s perfect for electronics. (Note: Wear a face mask, like an N95, or work in a very well-ventilated area when soldering.)From Single-Coils to Humbuckers
The first step occurs before the guitar reaches the workbench. We ordered three Seymour Duncan JB Jr. Strat pickups ($99 each), in Photo 2, which are single-coil-slot-sized humbuckers that, after being swapped in, will bump the upper mids and overall output the Squier Bullet Strat produces considerably.
Photo 2
For this mod, you’ll also need two 500k pots (we chose the CTS brand), and one 500k push-pull pot/DPDT switch—all easy to find online and displayed along with the clippers and pliers needed for this project in Photo 3.
Photo 3
Now, let’s get to started!
1) Detune the guitar to avoid flying-string accidents. Then, using a small wire cutter, clip the strings and remove them from the guitar. Remove the pickguard screws to release the pickguard. Put the screws in a small jar with a lid and put them aside, clear of the work area. You don’t want to be on your hands and knees looking for these later.
As you lift the pickguard, you’ll need to slide it slightly out from around the neck to pull it clear. Then, turn the pickguard over so you can see the wiring harness for the electronics.
2) Next, you’ll want to clip the ground wire that runs from the bridge to the volume pot (this wire looks like it’s coming out of the body of the guitar), as well as the white output-jack ground wire, which runs between the volume pot and an output-jack lug or pin—the small horn-like protrusion from the jack designed to accept wires. Then, clip the red, or “hot,” wire, which carries the signal to the output jack, from the center pin of the volume pot. Now, the pickguard is separated from the guitar and can be placed on an open, convenient spot on your workbench, for the next steps.
3) It’s time to strip the pickguard. After clipping the wires that run from the pickups to the volume pot casing switch, you’ll need to unscrew the pickups from the pickguard and pop them out.
Then, remove the screws—which go into your jar—on the 5-position pickup selector switch and gently remove its plastic top by pulling up on it. Now, you can pull the 5-way switch out of the bottom of the pickguard and save it for the rewiring process. You could leave the 5-way in place instead, but removing it gives you more space to work on the rest of the pickguard electronics assembly.
To remove the pots, gently pull up on the knobs and they will lift off the face of the pickguard. If they resist, consider using a cereal spoon to pry the dials up, and perhaps place a thin piece of cloth, like part of a t-shirt, under the spoon to keep the pickguard scratch-free. This method is less hazardous to the pickguard than using a flathead screwdriver.
Next, unscrew the nuts on the front of the pickguard that hold the pot assemblies in place. (They were revealed after you lifted the dials up.) You’ll probably need a pair of pliers to loosen them a bit, but, again, be careful not to scratch the pickguard. Turn the pickguard over again and clip the wires from the pots, which—reminder—we’re replacing, so don’t worry about saving them. (Standard CTS pots sell for about $7—cheap.) Then, the pots should pop right out. In Photo 4, from a bit later in the process, the pots, DPDT switch, and pickups have already been reinserted, but you can use this photo to view the nuts around the tone and volume control spindles.
Photo 4
4) Now, it’s easy to install the JB Jr.’s on the pickguard. Simply pop them through the pickup slots and screw them in place. Make sure the top of the letters reading “Seymour Duncan” face the neck for all three pickups, as in Photo 4. Use two small zip ties to keep all three four-conductor wires from the pickups together, and a piece of painter’s tape to temporarily hold the loose ends of those wires to the pickguard after the pickups are screwed in tight, to prevent the pickup wires from getting in your way as you work on other steps.
5) Time to install the new pots in the volume and first tone control positions, and then to install the push-pull DPDT switch in the tone control position closest to the guitar’s heel—the one farthest from the strings. While 250k pots are good for single-coil pickups, we’re using the 500k pots that are best for humbuckers here. And don’t forget the 5-way switch!
Let’s start by placing both pots and the push-pull in their places, sliding the shafts through the pickguard openings, and then screwing down the nuts to hold them in place—essentially reversing the process we used to remove the originals. (The 1/2" nut driver that you’ll use for the jack replacement we’ll do next also works for screwing down the nuts.)
Likewise, to reinstall the 5-way pickup selector, simply find your two screws and reverse how you removed it.
6) Basic Strat-style wiring—mostly—is the next step. A good standard Strat wiring guide, like the one on the Seymour Duncan website, may be a helpful visual aid. Wire the volume and tone pots to the switch exactly as on the diagram.
Duncan’s JB Jr.’s come with about 10 inches of four-conductor circuit wire already attached. Strip off about 3" of that wire’s outer casing. Then, you’ll see red, white, black, green, and ground wires. Peel about 1/2" of casing from the tips of each of those smaller, color-coded wires.
For the neck pickup, the green and bare wire are tied together and attached to ground—soldered to the top of the middle (tone) pot. You can see the secured pickup leads, ground soldering location, and overall layout in Photo 5.
Photo 5
The red and white go to the center right pin (looking from the smooth rear of the push-pull pot) of the on/on DPDT switch atop the push-pull pot. The black wire goes to the corresponding pin on the 5-way switch—the third lug from the front. (Reminder: Always tin your solder points!) You can get a good look at the DPDT and push-pull pot assembly in Photo 6.
Photo 6
For the middle pickup, the red and white wire are soldered together and bent back over the lead wire. You should use a piece of heat shrink tubing to mask it off. (Heat shrink tubing for guitar and bass wiring can be purchased via a number of online sources.) The green and bare wires also go to ground atop the tone pot, and the black wire goes to the number two lug on the 5-way switch.
And finally, the bridge pickup. The green and bare are tied together and, once again, soldered to ground on the top of the tone pot, while the red and white go to the left middle pin on the DPDT switch atop the push-pull pot, and the black wire goes to the corresponding pin—the front slot—on the 5-way switch. That provides coil-splitting, activated for the neck and bridge pickups, by pulling the rearmost knob up.
7) Let’s do one more thing while we’re here to beef up the tone. Let’s put a .022MFD orange drop capacitor in the tone control’s setup, which will roll off less treble frequencies than a higher value capacitor as the tone knob is turned down. The cap can rest atop the center (tone) pot, and let’s solder one of its bare wires to the back of the same pot’s casing for grounding. We’ll take the other wire and shield it with shrink tubing, and solder it to the outside pin on the tone pot. In Photo 7, you can see the completed wiring for the control set.
Photo 7
8) There’s one more control set wiring move.
The bottom lugs of the push-pull DPDT switch are both jumped to ground. This is what makes the coil-splitting possible, by selecting the ground wire or allowing it to go to output. (Use 22 AWG non-shielded PVC-insulated circuit wire for incidental wiring work like this.)
Then, reattach the red output wire from the output jack to the center pin of the volume pot. Follow that with reattaching the bridge ground wire and output-jack ground wire to the back of the volume pot casing.
(Or, you can wait and do these steps later if you are also doing the jack replacement.) Photo 8 displays all of our handiwork!
Photo 8
9) Lastly, replace the pickguard back onto the guitar with the screws you’ve saved and plug the guitar in to test the connections before screwing it back on. Done!
DIY: Replacing Strat Single-Coils with Stacked Humbuckers
Swapping the Output Jack
Our next job is replacing the standard 1/4" jack that lives behind the chrome boat-style output receptacle with a Pure Tone Multi-Contact Output Jack. It has four points of contact, versus the OEM’s two, and dual tension grounds to hug the cable sleeve in place from both sides, providing more reliable performance and better tone.
1) Start by removing the two jack-plate screws, and then remove the output-jack nut with a 1/2" nut driver. Carefully pull out the jack and boat assembly, (Photo 9) and snip the lead wires—the red is hot output and the white is ground—close to the jack, leaving plenty of wire from the guitar’s harness to work with. Strip the leads of those protruding wires about 1/4", for soldering later.
Photo 9
2) Grab your 60/40 rosin core solder and bring your soldering iron up to 750 degrees. While the iron’s heating up, slide some heat-shrink tubing down the output and ground wires. And when the soldering iron is at temperature, tin the wire leads and pins on the Pure Tone replacement jack.
3) Next, solder the hot (red) output and ground (white) wires to the two pins on the jack, being tinned in this photo (Photo 10).
Photo 10
When you’re done, slide the heat-shrink tubing that you slid onto the wire earlier over the pins and solder points. Then, heat the tubing with either a heat gun, hair dryer, or lighter (Photo 11) to make them shrink.
Photo 11
4) Finally, reattach the new output jack to the jack plate with a locking washer underneath, tighten the output-jack nut with the 1/2" nut driver, and reattach the jack plate to the body with the original jack-plate screws, as in Photo 12.
Photo 12
And now you’re ready to plug in and play!
