Humbuckers are meant to avoid electromagnetic interference. So does shielding, also. Is it worth, then, having both on your guitar or is it just a waste of money?
It’s not necessary to have shielding. (although it prevents the electromagnetic interference in the electric circuit). Why? Well, with the humbucker, there’s just no need for it. You probably won’t notice any difference. Also, a lot of high end guitars don’t have shielding, so there’s that, too.
There are, however, some functional differences between the interference suppressing ability of those two. Understanding them both will allow you to make the best choice.
Starting from the humbucker. Its double coil is build in a way that, while both coils will pick up the surrounding electromagnetic interference, the resulting signal from the two coils will add up to -almost- zero interference.
That way it allows the guitar player to get rid of the dreaded 60Hz hum that’s coming from the electric network.
It may look like no further action is needed. (No need for shielding.) (Given the strong premise of the humbucker being virtually custom-built to eliminate interferences.) This, however, is only partly true.
To understand why, we need some more in-depth knowledge on what is shielding and how it manages to keep your guitar’s sound clean.
In order to illustrate how it works, let me now introduce you a famous British scientist: sir Michael Faraday. He, in 1836, well before Leo Fender changed music history. Faraday noticed a strange phenomenon.
He observed that if he applied electric tension to an hollow conductor, the electric charges stayed on the surface. Therefore, those charges are unable to have any influence on the interior of the conductor.
Hence, any hollow conductor may be seen as a Faraday’s cage. You probably already know that this is the reason why staying in a car during a thunderstorm will keep you safe from thunders striking you.
Which is, by the way, way less probable than you think. But in this case, it’s way better to be safe that to be sorry.
Interference May Come From Other Cables…
What does this Faraday guy has to do with electric guitars? Well, there’s more than pickups in the electric circuit of a guitar. You always have a more or less wide array of cables. Those connect the pickups to the pots and then to the output jack.
Compared to the hundreds of feet of copper wire in a pickup, this cables make for some pretty lame antennas. Still, they are able to pick some external electromagnetism which will then be driven directly to the amplifier. That will make every interference audible.
Unless, as you may have already guessed, you build a Faraday cage around the control cavity and the pickup routing.
What Does Shielding A Guitar Do?
So, here we have our functional difference. Humbuckers will eliminate the interference at the pickup level, while shielding will prevent interference to occur in the rest of the circuit so both are necessary. Or not?
As mentioned, the guitar’s electric circuit is much less prone than the pickup to catch electromagnetic fields from the environment. Many guitarist will never notice any strange noise from their instruments. Even without any shielding.
Just go and check any Gibson L5. You’ll find that it lacks shielding completely. This is also true for a good number of other high-end guitars.
Part of it is related either to tradition or to production costs. No guitar in the 50’s or 60’s had shielding. Therefore, covering the control cavity with copper makes the building costs rise.
In fact, unless you usually play in an environment that’s rich in electromagnetic fields, shielding may be unnecessary.
Environment In Which You Play Matters
Just compare the electromagnetism at a jazz venue to the one present at a rock concert. In the first case we will most of time have a quartet or a quintet. Drums are seldom amplified and guitar and double bass go into moderately sized amps.
We’re talking about a genre where the Roland Jazz Chorus is considered to be almost too powerful. Cost-conscious musicians just opt for a Roland Cube 40. Most of the electromagnetic pollution will likely come from the surrounding cellphones.
At the rock gig, on the other hand, the guitarist is playing in front of a wall of stacked Marshalls. The bass player does the same and the rhythmic guitar player doesn’t want to disappear in the mix.
Drums are amplified and so is the voice. Big powerful lights illuminate the stage, where we also have a lot of mixers and mixed gear.
The cellphone will be probably still distinguishable, with it’s characteristic interference in triplets. But here we have a lot more things happening around that may ruin the sound of the guitar.
To each his own. If you’re already happy with the sound of your guitar there’s no need to add shielding.
Does Shielding Guitar Affect Tone?
One of the big advantages of shielding, however, is that it’s an option that only has pros and virtually no cons. Especially if we’re talking about tone.
Shielding, if well done, will have no impact on the tone of the guitar. The instrument will be just quieter in any environment and you’ll be able to play with your smartphone in your pocket, if you think it’s wise.
Or course, a sloppy job will give you back an instrument that’s way noisier. It’s quite easy to mess with the guitar’s ground. But let’s assume you have a good tech…
Having concluded that shielding the control cavity is a good move and you may consider it even if you don’t really need, let’s move on and discuss the shielding of the pickup cavity.
This is without doubt a job that’s better intended to reduce single coil’s hum. Once you bought enough copper film to shield the control cavity, you may be tempted to also shield the pickup itself.
Clearly you won’t be able to build a complete Faraday cage around the pickup unless you cover it with copper.
In this case you will have a funky looking guitar that’s unable to make any sound. That’s because you have now insulated the pickup from the strings… not a good idea, isn’t it?
You’ll only be able to shield the sides and the bottom of the cavity. You may wonder if it has any effect at all on further silencing your guitar.
As a principle, the effectiveness of a Faraday cage that’s open on one side will be greatly reduced. If you plan to shield an humbucker, it would better have a metal cover to help. Otherwise you’ll likely hear no difference at all.
So far we have a mixed answer to the question if humbuckers need shielding. There’s surely no harm in doing that. Shielding the pickup itself is generally done once you shielded the control cavity. And it has no drawbacks if properly executed and without any ground shorting.
Still, an uncovered humbucker will probably not benefit directly from a shielding that may not have been necessary, in first place.
Do EMG Pickups Need Shielding?
Someone may wonder how things turn out when, instead of a classic passive humbucker we use an active set. Let’s say from EMG.
In this case shielding is even less important, as EMG pickups are already shielded. Also, the active circuitry is way less susceptible to interference. EMG goes so far to suggest that even grounding the bridge is not necessary with his pickups, go figure!
But, despite all EMG’s claims (and while it’s true that shielding the pickup routing is a waste of resources), shielding the control cavity has been reported to be able to reduce noise for some guitars and basses that were particularly delicate about electromagnetic fields.
Get Yourself A Great Humbucker
While shielding may be unnecessary, having a humbucker certainly is necessary.
That’s why I’d like you to have a look at what are some best humbuckers for clean tone, jazz or blues in 2020. Check the article from this site.
I hope this article gave you a valuable information about this topic. If you enjoyed reading it as much as I’ve enjoyed writing it, I’m happy about it.
Don’t forget to check out other interesting articles about various guitar topics and issues!
Cheers, and rock on!