Shielding Fender Single Coil Guitars

[akpasta]

Hi All,

I've got a vintage Fender XII and an alt reality XII, both with Curtis Novak pickups. With compression added (Janglebox), they are very noisy, the kind that goes away when you touch the strings or bridge or metal. Also if you run it straight without any compression, there is a "normal" amount of hum and it's not really problematic. It's not a grounding issue, and I have other guitars with single coil pickups (rickenbackers, and a fender jaguar) that don't have this problem with the janglebox, so I am curious if copper shielding might help me on my two fender xii's.

It seems simple enough to install shielding in the pickup cavity and the back of the pickguard, but seems a bit challenging to install shielding around the wires, and I definitely don't want to de-solder anything. Is it worth it to do one, but not the other? Any tips?

Thanks!

[JackFawkes]

I'm not trying to be that guy, but do you not usually touch the strings when you play?

If the noise goes away when you touch the strings, then your grounding is correct; and shielding won't reduce that buzz any more than touching the strings does.
But if you're talking about the additional noise that single coils make when you're already touching your strings, that's hum and shielding does literally nothing for that.

I'm not trying to be pedantic, I'm trying to make sure I understand what you're experiencing to possibly help. I absolutely hate extraneous noise and I've done a lot of comparative testing and trial-and-error trying to understand it, and what can (and can't) be done about it.
(I also think a big part of my frustrations on this subject are the fact that half of the information on the internet is either unclear or misleading, and most people misuse and/or misunderstand the terms hum and buzz - they are in fact two different kinds of noise that come from two different phenomena, and both sound similarly bad)

Jack

[akpasta]

Ya I hear you.

To clarify I’m referring to the buzzing that occurs when not playing and not touching strings or any metal on the body. It’s a pain to deal with when recording. Once I touch the strings or metal or start playing it’s no big deal. I have a noise gate but the buzz is so loud it’s hard to configure correctly.

I am hoping shielding can correct that idle buzz that occurs when not touching strings or any metal.

Thanks!

[JackFawkes]

Ok! If you're happy with the noise level when simply touching the strings and you're looking to get a similar level of buzz reduction when you're not touching the strings, then shielding is the answer you seek.

If you're shielding all sides of the cavities and wire routes, then there should be no need to shield the wires themselves.

...I just looked at pictures of what an XII looks like under the pickguard...
Just to be clear, since the pickups themselves take up one entire "side" of the pickup cavities and the metal control plate does the same for the control cavity, if you shield the other 5 "sides" of those cavities you shouldn't need to worry about shielding the wires themselves.)

Jack

[akpasta]

Hi jack thanks for the info. What about shielding the tunnel that goes from the pickup cavities to the control cavity. Would I need to shield that?

[JackFawkes]

Ideally you should, since it is a vector that buzz can enter through; but those tunnels are a pain.
Probably the easiest way to shield the tunnel is to try to find a copper tube or aluminum wire mesh sleeve that fits in it, and run the pickup wires through that. (Make sure that the tube/sleeve gets connected to the cavity shielding at both ends of the tunnel, and test continuity through it.)

Jack

P.S.: An aluminum wire mesh sleeve is basically the same thing as the shield in shielded wire.

[countertext]

“Jimi didn’t need no damn shielding.”

[jvin248]

“Jimi didn’t need no damn shielding.”

Jimi didn't have a cell phone in his pocket nor two laptops and a rack of computer servers in his studio either


OP, shielding won't take care of the 'hands free buzz' problem. You need to have the habit of rolling the guitar volume knob off when you are not playing. The thirty feet of guitar strings hanging out there are your antenna.

Shielding will fix the other hum problem. Turning off the guitar volume knob will also fix this issue between songs but during slow or quiet passages of a song can pick up this hum in recordings.

Make sure you use shielded cable from the volume pot to the jack, not two separate wires like Fender likes to do -- for the same reason we use shielded cable from the guitar to the amp. Then full cavity shielding for the rest of the cavities. Fender Strats and JMs I've even put foil on the inside of the pickup covers, with a short flag loop that is run to the pickguard shielding -- you need to be patient and careful if you do this as you can nick the bobbin wires or short the pickup out if not being careful.

.

[Nudger]

Hi All,

I've got a vintage Fender XII and an alt reality XII, both with Curtis Novak pickups. With compression added (Janglebox), they are very noisy, the kind that goes away when you touch the strings or bridge or metal. Also if you run it straight without any compression, there is a "normal" amount of hum and it's not really problematic. It's not a grounding issue, and I have other guitars with single coil pickups (rickenbackers, and a fender jaguar) that don't have this problem with the janglebox, so I am curious if copper shielding might help me on my two fender xii's.

It seems simple enough to install shielding in the pickup cavity and the back of the pickguard, but seems a bit challenging to install shielding around the wires, and I definitely don't want to de-solder anything. Is it worth it to do one, but not the other? Any tips?

Thanks!

I use same set up, My janglebox is the black one "old".
Just tried my 3 XIIs.
Two shielded one not..
The non shielded has a pronounced buzz with fingers off strings. Tried my unshielded strat.. Same.
None of my XIIs have tunnels.

[akpasta]

Hi All,

I've got a vintage Fender XII and an alt reality XII, both with Curtis Novak pickups. With compression added (Janglebox), they are very noisy, the kind that goes away when you touch the strings or bridge or metal. Also if you run it straight without any compression, there is a "normal" amount of hum and it's not really problematic. It's not a grounding issue, and I have other guitars with single coil pickups (rickenbackers, and a fender jaguar) that don't have this problem with the janglebox, so I am curious if copper shielding might help me on my two fender xii's.

It seems simple enough to install shielding in the pickup cavity and the back of the pickguard, but seems a bit challenging to install shielding around the wires, and I definitely don't want to de-solder anything. Is it worth it to do one, but not the other? Any tips?

Thanks!

I use same set up, My janglebox is the black one "old".
Just tried my 3 XIIs.
Two shielded one not..
The non shielded has a pronounced buzz with fingers off strings. Tried my unshielded strat.. Same.
None of my XIIs have tunnels.

Wow beautiful! Thank you! So shielding “should” work!

The vintage xii has a tunnel so my mileage may vary. I’m considering just taking the vintage one to a shop for shielding but we’ll see.

[JackFawkes]

Make sure you use shielded cable from the volume pot to the jack, not two separate wires like Fender likes to do -- for the same reason we use shielded cable from the guitar to the amp. Then full cavity shielding for the rest of the cavities.

I hate butting into other user's posts, but I want to make just one clarification here...

On a Fender XII, the output jack is in the control cavity. If you shield a control cavity that includes the output jack, there is no reason to use shielded wire from the volume pot to the output jack; those wires are already being shielded by the control cavity shielding.
On a Fender Stratocaster, the output jack is in its own cavity and the wires pass through a tunnel to get from the volume pot to the jack; in that situation it's generally much easier to just use shielded wire than to shield the jack cavity and tunnel.

So just to be clear, if the output jack is in a cavity that is already properly shielded, you will get no additional benefit by using shielded wire from the volume pot to the jack.

[øøøøøøø]

A few things to point out/questions to answer here before doing any work at all:

The strings typically need a ground/earth connection. Verify with an ohmmeter that the bridge has electrical continuity with the rest of the circuit. If it doesn’t, fix this issue.

Copper or aluminum shielding will only help with electrostatic interference. It will not help much with magnetic interference, or interference of low frequency.

To help with low frequency radiation like 60Hz or 120 Hz, or radiation from electromagnetic sources like transformers, you’d need a high-permeability foil like Mu Metal or Ultraperm. This stuff is really expensive and fragile (just bending it around a corner without re-annealing can destroy its shielding properties!) so most guitar techs don’t work with it

If cell phone type interference is your primary issue, or if it’s just higher harmonics of some noisy hash you’re trying to address, copper shielding may well do something—but don’t expect miracles

For a recording/acoustics analogy, think of copper shielding like a thin gobo. It can attenuate higher frequency stuff and “cast a shadow” that might be helpful in some circumstances, but it won’t block the lower frequency stuff. It won’t keep the metaphorical bass out of your acoustic guitar mic (60Hz out of your guitar signal).

And in order to really do the most, you’d need to be fully enclosed (not practical with guitar pickups, which perform best when the pickups themselves are exposed to the strings).

But even if fully enclosed (faraday cage), the metaphorical “walls” in our analogy would be too thin to block the low frequencies. You’d need magnetic permeability for that.

There are also at least some theoretical downsides—depending how close your signal-carrying wires and pickups are to the shielding (and how long they are), you’re theoretically adding some amount of capacitance to the system. This probably isn’t going to be very significant, but since we live in an era where people sometimes pay lots of money for extremely low-capacitance cable it’s worth mentioning

[akpasta]

Heyyy a little update. I bought some shielding tape from stew Mac and carefully coated the pickup cavity and control cavity, didn’t even bother trying to cover wires or the tunnel between cavities and… success!!! Guitar is almost completely quiet even run run through tons of compression!

I did have to wrap the pickup switch in electrical tape cuz at first it was shorting out but that was the only trouble.

[JackFawkes]

That's awesome! Nothing more satisfying than a project turning out the way you wanted it to.

Jack

[DeathJag]

Excellent! I had a similar experience with a JM that I laboriously shielded and now it is very quiet. What is crazy is how some guitars that have no shielding are just as quiet as the guitars with shielding. How is this explainable?!!!

@øøøøøøø Thank you for the technical info, I love that stuff. I want to go back to school for electronics, I'm super interested but I can't self-motivate. I've been trying to figure out how to read schematics and relate them to the boards I've got but it instantly goes over my head. But tidbits like you've dropped are really cool.