How to Shield an Electric Guitar to Reduce Hum

Why Your Guitar Hums

Hum and buzz in an electric guitar usually come from electromagnetic interference. Single-coil pickups are particularly susceptible because they pick up stray fields from lights, transformers, and other electronics. Humbuckers cancel some of this noise, but even they can be affected if the guitar's internal shielding is poor. Learn more about the differences between single-coil and humbucker pickups.

The noise you hear is often a low-frequency hum, but you don't need to know the exact frequency to fix it. The goal is to create a continuous conductive shield around the electronics that intercepts the interference before it reaches the pickups and wiring. This is a practical modification that any guitarist can do with basic tools.

How Shielding Works

Shielding works by creating a Faraday cage around the sensitive electronics. A conductive layer, either paint or tape, lines the inside of the pickup and control cavities. This layer collects the interference and sends it to ground through a wire connected to the back of a potentiometer or the output jack's ground lug. For the shield to be effective, it must be continuous: every panel must be connected, and there must be no gaps.

The concept is similar to how the body and wood of a guitar shape its acoustic tone, as described in Martin's guide to acoustic guitar types. On an electric guitar, the pickups and wiring are the primary transducers, and shielding only affects the electrical noise, not the sound you want to hear.

Materials and Tools

The two most common shielding methods are conductive paint and copper tape. Conductive paint is a liquid copper or nickel coating that you brush onto the cavity walls. Copper tape is self-adhesive and easy to apply, but you must be careful to avoid shorting against component leads. Both work well when applied correctly and grounded. If your guitar has active electronics, such as a preamp described in Martin's acoustic electronics guide, you'll need to shield the battery compartment as well.

• Pickup and control cavity covers
• Small brush for paint
• Copper tape or conductive paint
• Ground wire
• Soldering iron (optional)
• Multimeter for continuity checks

Prepare the Guitar

Start by removing the strings and the pickguard or access plate. On a strat-style guitar, you'll usually have a pickguard that holds the pickups and controls. On other body styles, there may be a backplate. Once the electronics are exposed, photograph the wiring so you can put everything back correctly. Clean the cavity with rubbing alcohol to remove dirt and grease, and scuff any painted surfaces lightly with sandpaper so the shielding material adheres well.

Shield the Pickup and Control Cavities

Apply the shielding to the inside of the pickup cavities and the control cavity. If you're using paint, apply two or three thin coats, letting each dry per the manufacturer's instructions. If you're using tape, press it down firmly and overlap edges for continuity. Make sure the shielding covers the walls but does not extend onto the face of the guitar where the pickguard sits, unless you plan to shield the back of the pickguard as well. Many players also shield the back of the pickguard itself.

A common technique is to run the shielding into the wiring channels that connect the cavities, so everything is electrically linked. Once all cavities are coated, connect each section with a small strip of conductive tape or a wire. This ensures the shield is continuous from one cavity to the next.

Ground the Shield

The shield does nothing unless it's grounded. Run a wire from the shielding to a common ground point, typically the back of a volume potentiometer. Solder one end to the shield (using a small patch of tape or a screw terminal) and the other to the pot's case. If your guitar has a ground wire already, you can attach to that. After grounding, use a multimeter set to continuity to check that every piece of shielding connects to ground. If you measure no continuity, find and fix the break.

Test and Reassemble

Before screwing everything back together, plug the guitar in and turn the volume up to test for hum. Move the guitar around and touch the strings; you should notice a significant reduction in noise. If hum persists, check for gaps in the shielding or a poor ground connection. You may also need to check the pickup height and output jack for good contact. Once you're satisfied, reassemble the guitar and enjoy a quieter signal.

When Shielding Isn't Enough

Shielding reduces electromagnetic interference, but it won't fix hum caused by ground loops or bad wiring. If your guitar still hums after careful shielding, you may have a grounding issue. Learn how to fix electric guitar grounding hum and check the output jack. Also, if the hum is only present when you touch the strings, that's often a grounding problem, not a shielding issue. For persistent noise, consider upgrading to humbuckers or using a noise gate.

Will Shielding Change My Tone?

No. Shielding adds a conductive layer inside the cavities, but it doesn't touch the strings or pickups. The wood and body design, as explained in Martin's guide to acoustic guitar types, influence the guitar's acoustic voice, but on an electric guitar, the pickups and electronics are the main transducers. Shielding only reduces electrical interference, so your tone remains as it was. As with any guitar modification, you can always reverse the process if you ever want to.

What to pick for your use

Questions

Will shielding change my guitar's tone?

No. Shielding only affects electrical interference, not the tonal characteristics of your pickups. The tone is determined by pickups, woods, strings, and amplification.

Can I use aluminum tape instead of copper tape?

Yes, any conductive tape will work, but copper and nickel are common. Ensure the adhesive side is non-conductive if it's not designed for shielding; some tapes have conductive adhesive.

Do I need to shield the back of the pickguard?

It's recommended, because the pickguard area can let interference reach the pickups. Applying shielding to the back of the pickguard creates a complete shield when the pickguard is installed.

How long does shielding last?

With proper application, shielding is permanent. Conductive paint may require a touch-up if scratched, but tape usually lasts indefinitely unless lifted.

Can I shield a guitar with active pickups?

Yes, active pickups also benefit from shielding, but be careful not to short the battery or preamp. Some active systems have built-in noise cancellation, so shielding may be less critical.