Guitar Wiring Tips

There are several factors to consider when it comes to guitar wiring. Perhaps the biggest issue is eliminating unwanted noise. If you've ever changed a pickup, volume/tone control, switch, or jack and ended up with some annoying hum and buzz, you know what I'm talking about.

After years of trial and error and a bit of research, I've found that the major factors for good guitar wiring are:
  1. Wires must be well insulated and of the proper gauge and type.
  2. Controls and circuits must be properly grounded, and perhaps shielded, to reduce hum and noise.
  3. Wiring connections must be mechanically and electrically solid.
If your guitar is just too noisy when your not playing, the following wiring tips may help.

Wire Insulation
Some guitar techs and players swear by vintage cloth covered wiring and even claim it improves the guitar's tone. Besides looking pretty cool, cloth insulated wire is also pretty easy to work with since you don't need to strip the ends, just push back the cloth and solder.

But from what I've found, the type of insulation has no real affect on the guitar's signal or tone as long as it, well, insulates the wire. Damage to the insulation that exposes the wire (like being melted by a wayward soldering iron) can cause a short and may introduce signal noise. Even if the wire is not exposed, a thin spot in the insulation may still cause problems.

The most common wire insulation is PVC (polyvinyl chloride), which melts very quickly when it gets too close to a soldering iron. Using wire with heat-resistant insulation such as Teflon® (PTFE) and Tefzel® (ETFE) greatly reduces the chance of melting by a soldering iron.

Both Teflon and Tefzel insulation are harder to strip than PVC and require high quality wire strippers for best results. However, some claim Tefzel is easier to strip than Teflon.

After replacing several PVC insulated wires that got too close to my soldering iron, I finally started using Tefzel wire for most all my wiring projects. You can get Tefzel wire in either unshielded or shielded varieties. Unshielded wire works best for short length wiring of controls, and shielded wire is the best choice for longer length wiring (see Shielding below).

Wire Type & Gauge
There are many choices when it comes to the type and gauge for guitar wiring. Most wire used in guitars is tinned copper. Some guitar techs also use silver wire, which is usually insulated with Teflon. Silver wire is more expensive and doesn't seem to offer much over tin plated wire. Also, silver tends to corrode a lot easier and faster that tin.

Stranded wire is more durable and less prone to break than solid core wire. Repeatedly bending solid core wire will weaken and eventually break it, which is why I prefer stranded wire.

I generally use 24 gauge stranded tinned copper wire. This gauge is small enough to work in tight places and is fairly sturdy. But any gauge from 22 to 26 should work well. Wire smaller than 26 gauge tends to be too fragile and larger than 22 gauge is generally too bulky.

Grounding
All metal parts (bridge/tremolo) and metal component bodies (pickups, potentiometers, switches) must be grounded. Guitars should have a ground wire from the pickups and bridge or tremolo claw that must be connected to the same ground as the wiring circuit—the signal ground.

Potentiometers with a metal body are usually grounded by soldering a ground wire directly to the metal body. Switches typically have a ground lug for connecting a ground wire. Ground wires should be insulated whenever possible to avoid short circuits. Note that you only need to ground pots and switches this way in an unshielded control cavity (see Shielding below).

Ground Loops
The most common grounding problem with guitar wiring is a ground loop. A ground loop exists when there is more than one path to ground. It may sound like a good idea to just ground everything to each other, but you'll end up with a ground loop and a lot of hum and noise.

To avoid a ground loop, make sure each component has only one path to ground. Use a star-style ground with each component grounded to a single common ground point such as the output jack sleeve (ground) connector. You can also use a ground lug (a small screw attached to the body inside of the control cavity) to connect the various ground wires such as those from the pickups and bridge to the output jack ground.

Shielding
Lining the control cavity with copper shielding is an excellent idea. Make sure each component is connected to or in contact with the shielding and not to any other ground point. The shielding should be connected to the signal ground on the output jack.

Shielding the control and pickup cavities in your guitar will reduce radio frequency (RF) and electromagnetic (EM) interference. Use self-adhesive copper foil for the shielding, which comes in various widths and lengths.

Apply shielding to the inside of the cavity and the back side of the control cavity cover or pickguard. If you get copper foil with conductive adhesive, you won't need to solder the seams. Your local guitar store should sell copper foil shielding or you can easily find it online.

Long wire runs like those from the Les Paul pickup selector switch should use shielded wire cabling to prevent RF and EM interference. Generally, any wire that is more than a couple of inches long in an unshielded control cavity should use shielded cabling.

Next...
In another post, I'll go over the ins and outs of soldering and what I learned from the mistakes I've made.