By Ed Malaker
In this post, we’ll take a look at shielding a Gibson SG. The SG is one of the easiest guitars to shield because they usually have two humbucking pickups that eliminate most of the noise from the start. Because of this, you don’t need to apply shielding to the pickup cavities; you only need to cover the electronics cavity with a conductive material to complete the job.
Not many tools are required for shielding a Gibson SG. You will need a screwdriver to remove and replace the back cover, a soldering iron, and solder. You will also need a shielding material. We recommend copper tape as a shielding material, but you can use aluminum tape or foil as well as conductive paint. You will also need a short piece of wire to connect the shielding to the circuit.
First, remove the back cover. Then carefully remove the electronics, paying particular attention to where they go so you can replace them later. If you’re new at this, you might want to take a photo before you begin, so you’ll have a reliable reference when you’re ready to reassemble.
Apply Shielding Material
The next step is to apply the shielding material. If you’re using copper tape, the adhesive is conductive so that you can overlap it without worry. Aluminum tape may not have conductive adhesive, so you will need to make sure there is a good connection between layers. Conductive paint is the easiest to apply, but it is the least conductive. In the ’60s, Gibson sold a brass cavity shield that was the perfect size, but they’re expensive and hard to find.
Apply the conductive material to the entire cavity, including the little lip that the cover plate fits into so you can screw it tight. Apply the shielding material to the inside surface of the cover plate as well. When you replace the cover plate, the shielding material on the cover should touch the shielding material in the cavity and create a conductive metal box.
Replacing the Electronics
Replace the electronics the same way you removed them, then solder a short wire from the shielding material to the back of one of your volume pots, and you should be good to go.
When you replace the electronics, you may notice that the metal casings on your tone and volume pots, as well as the switch and output jack, are all (should be) in contact with the metal shield. This connection eliminates the need for any grounding wires that connect these components. There is usually a wire from the back of the volume to the back of the tone, for instance. That wire is no longer needed.
This “double” grounding that occurs when you shield a guitar and replace the electronics the same way they were, is the source of a good argument.
Side A states that because of the components connected by shielding and the original wire, we create a ground loop. Ground loops are bad because the current flowing between the two grounds creates audible noise (simple explanation).
Side B states that to have a ground loop, you need two different paths to earth ground, and we only create multiple paths to our output jack, which will lead to one earth ground. Therefore, you cannot create a ground loop inside a guitar.
While Side B is technically correct and your guitar will work fine, there are still some reasons to remove the extra connections. The first is that the double connections could create a physical circle, and wire bent in a circle can create an antenna for some noise. However, the shielding should prevent the antenna from being able to receive any signal. The second reason would be redundancy. It’s the same as connecting two wires from your tone to your volume.
That’s all there is to shielding a Gibson SG. If you’re using an SG that has P90s installed, you will want to add shielding to the pickup cavities as well. Make sure the shielding in the pickup cavities connects to the back of a volume pot.
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