DIY Workshop: How to rewire a Les Paul
Think twice before you install that set of boutique PAF clones – you might be surprised by how much extra clarity you can get from your beloved Gibson by simply upgrading the wiring and components.
There are plenty of reasons to rewire a Gibson-style solidbody. Pickup swapping is commonplace but most people leave the controls and wiring as is. You may be happy with your pickups but if you research potentiometers and capacitors, you might discover that there’s still headroom to improve your guitar’s tone and response.
Perhaps you’ve finally lost patience with that noisy, crackly switch and want to upgrade the other components and try out some trick wiring while you’re at it. If your guitar wasn’t that expensive to begin with, upgrading the pots and caps may improve tone and reliability.
The cheapest option is to buy all the components and wire everything yourself – but this can prove fiddly. DIY Les Paul harnesses can be a challenge for soldering novices, and even those with expertise would struggle to better the Six String Supplies prewired harnesses featured here. Fancy wiring your Les Paul Jimmy Page-style for various out-of-phase, in series and coil-split options? It’s a seriously daunting proposition.
Prewired harnesses are sold by various companies and make rewiring your guitar considerably easier. Les Paul harnesses are available with long and short potentiometer shafts, so you may need to remove a couple of potentiometer nuts and pointer washers to determine which you need. If you end up ordering long shafts by mistake, you’ll still be able to use the harness, but if the maple cap is too thick for short shaft pots, you won’t be able to install it.
We’re approaching this as a complete rewiring project, and stripping everything out of our donor guitar. But if you’re only interested in doing a partial job, that’s fine. You can replace the controls but leave the switch and pickups where they are or, if you’re only replacing the switch wiring, you can leave the pickups and controls in place, though you may need to lift the pickups out of the body in order to send the switch wires through the routed channels. Hopefully there’ll be something for everybody in this DIY Workshop. Use whatever you need.
Whether you’re rewiring a Les Paul or wiring one up for the first time, there’s a series of steps you should follow for the best results. Unlike traditional Fenders, some Les Paul electronic components are installed from the front and others from the back. Unless you approach this systematically, you’ll have bits falling off the guitar every time you flip it over, which you’ll need to do more than once.
Begin by removing the rear plates that cover the control and switch cavities. Place the bits you remove somewhere safe so you don’t lose them. The plastic containers from takeaway meals are ideal – if you’re working on a few guitars at once, just put the lids on and label the contents.
If the cover plates are wedged into their rebates, don’t try to prise them out. Instead, roll some masking tape into a loop with the sticky side outwards, place it onto the plate and press down firmly. The tape will stick to the plate and your fingers, and it should lift out easily.
Have your soldering iron at the ready because it’s time to start unhooking those wires. If you’re just changing the switch, you’ll only need to disconnect the wires leading to the output jack and volume controls.
The signal wires will be connected to the centre tags of the volume pots and the ground connections may be made to the pot casings or a separate ground connection – on a PCB or tag strip, depending on the guitar. The best way to disconnect the jack socket is to unscrew the plate, pull it clear of the body and desolder the wire from the socket.
If you’re taking the controls out, you’ll need to disconnect the pickup wires too, along with the ground wire from the bridge that enters the control cavity through a hole in the side and probably connects to one of the pot casings.
Back to front
Flip the guitar onto its back and work from the top. If you haven’t done so already, you’ll need get the strings out of the way. But first, measure the bridge height using a ruler or, better still, digital calipers, so you can easily return your guitar to the way it was set up before work began. Remove the strings, tailpiece and bridge, and set them aside.
To remove a pickup, take out the four surround screws, lift the whole assembly off the guitar and carefully draw out the hookup wire along with it. If the guitar has two pickups, it may be easier to remove the bridge unit first but the procedure for removing the neck pickup is identical.
Before detaching the switch wires, it’s advisable to label them if you intend to keep the same switch. Removing the knurled nut that holds the switch in position is easy but doing so without damaging the poker chip – or the finish in the absence of a poker chip – is less straightforward. Use the correct tool for the job, such as an Allparts toggle-switch box spanner (part number LT-4201-023).
If you can’t get one or don’t want to, and opt to use pliers instead, be sure to protect the poker chip or finish around the switch with masking tape. You could wrap tape around the jaws of the pliers too, but if you mess up, don’t say we didn’t warn you.
Drop the pots
With the knurled nut loose and the chip removed, you should be able to pull the switch out, and the wires should follow. On occasion, wires may be bundled together with plastic cable ties. If that’s the case, remove them before pulling the wires through so there’s no chance of them snagging the body’s wire channels.
Now it’s time to flip the guitar back onto its front. It’s always advisable to conduct work like this on a soft surface – carpet offcuts are suitable, as are folded blankets or bath towels. Take care to set any parts you remove to one side, especially sharp metal ones.
Again, pliers are not the best option for fixing and removing pots. For CTS pots, you need a half-inch socket. Undo and remove the four nuts, along with the washers, and allow the controls to drop into the cavity. Congratulations, you’ve turned your guitar into a husk. Now you have carte blanche to do whatever you want to it.
Taking back controls
Getting a prewired harness into a guitar is trickier than mounting individual components. It’s best to work with the top facing upwards and lift the controls in from underneath – each pot has a star washer over its shaft to prevent it from spinning once it’s been bolted down, and if the pot shafts are lifted up into the holes, gravity keeps the star washers where they’re needed.
Hold the controls in place with one hand and use the other to slip the pointer washers and nuts over the pot shafts, and turn each until the nuts have grabbed onto the threads. With both hands now free, use a half-inch socket to tighten them further, making sure the pointers line up. Tightening by hand is fine too. You don’t need to crank them right up with a wrench handle attached to the socket. We’re talking potentiometers here, not cylinder heads.
Keep the ground wire that leads from the tailpiece posts tucked away to one side throughout, until it’s time to reattach it to one of the control pot casings – the neck volume pot being the usual spot. Melt a little solder onto the pot casing, press the ground wire into the solder using the iron tip, and add a bit more solder. Use a flat-head screwdriver to hold the wire down as the solder cools.
For this project, we’re installing a Six String Supplies’ pre-wired Switchcraft switch that comes with colour-coded hookup wires. Look inside the switch cavity and you’ll see the opening of a channel that runs through both pickup routs and leads all the way to the controls. The wires go into the channel first and should emerge in the neck pickup rout.
You can pull gently on the wires as the switch is introduced into the cavity. It’s a tight fit so remove the switch tip first, and you may need to bend the wires slightly near the switch. Once it’s in position, place the poker chip over the switch and screw the knurled nut onto the switch to secure it.
In this instance, we had to re-use the original knurled nut because it had a little more depth than the one that came with the Six String Supplies kit, and this LP Traditional needed it. If you bought that Allparts toggle-switch box spanner, you can use it to tighten the switch in place.
Continue feeding the switch wires through the body and eventually they’ll emerge into the control cavity. The yellow tagged cable connects to the output jack, so bend that back and tape it out of the way for the time being. The red and blue tagged wires go to the neck and bridge, respectively.
If you’re connecting up a switch that you wired yourself, make the jack-socket wire noticeably longer. You can then use the continuity setting on a multimeter to determine which wires correspond with the neck and bridge switch positions.
Assuming you’re working with vintage-style braided wire, melt some solder onto the top of the two volume pot casings before attempting to connect the switch wires. Cut the wires to length – leaving some extra wiggle room – and draw back the braid to expose about 10mm of the black cloth-covered wire inside.
Draw back the cloth covering to expose a few millimetres of wire, twist the strands together and tin the wire by melting solder into the strands. Tin the braid wire in the area where it will ground against the pot casing too. Solder the signal wire onto the centre tag of the volume pot first, then melt solder onto the braid as you use the iron tip to press it tightly against the pot.
When the solder flows, press the braided wire down with a flat-head screwdriver, remove the soldering iron, and allow the solder to cool. With both switch wires soldered to the volume pots, it’s time to install the pickups.
Pickup hook up
The procedure for wiring the pickups onto the volume pots is almost identical to the switch wiring, the difference being that the signal wires are soldered to the outside tags. Start with the neck pickup, feeding the wire through to the controls and fixing it in position with the surround screws. Flip the guitar over, solder the wire onto the appropriate volume pot – the one nearest the bridge – and repeat the procedure for the bridge pickup.
To complete the installation, slip a plastic tube over the jack wire that has, until now, been taped out of the way. About 120mm of mains-cable insulation stripped off the wires is ideal. Feed the end of the wire through the hole for the output jack, solder the wire back onto the jack socket and screw the mounting plate back onto the body. You’re done – but be sure to check the circuit works before restringing the guitar.
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