shielding a tele problem

[jeremylangford]

I've always really needed to shield my mexican fender tele due to an extreme amount of buzzing I get when I play at my church. I found the GuitarNuts site and tried following the instructions for shielding a tele.

After getting my bridge cavity shielded with copper tape, i realized that my tele is slightly different than the tele used in the guitarnuts tutorial. My tele's bridge pickup has two wires coming from it, a black one and a yellow one. The problem is in the fact that my black wire was soldered by Fender, in two places, to a piece of metal with a circle in it made to stick a screw through. It is made so that you can screw down the wire to the bottom of the pickup cavity and also to the actual bridge pickup. I guess this was just a way to keep the wires organized.

When i found this difference, I just poked a hole through my copper tape on the bottom of my bridge cavity where one of the screws that is soldered to the wire is supposed to go, and screwed it back like it was when I found it. After thinking about it, I realized that this could screw up my shielding, because my wire is now touching my copper foil.

Here is three pictures to help explain what Im talking about.







I just dont know whether I need to cut a circle through my copper tape around the screw, so they are not touching, or fill in the hole that the screw made and cover the piece of metal with rubber or something to keep it from ever having contact with the copper, or anything else.

Any help will be greatly appreciated
,thanx

[ashcatlt]

Welcome.

That circle thing is meant to go around the pickup screw at the bridge, and act as "string ground" as well as the signal return for the bridge pickup. It is, in fact, essential to the shielding of that cavity since it's the only continuity between your copper foil and the rest of the circuit.

BTW - You don't need to move it to the pickup screw, but you could. Course then you'd have a hole in your shield that you don't really need...

[gitpiddler]

Jeremy, welcome-I hope you can learn as much here as I have. If it were me, I would cut the signal ground from the shield, which still needs to touch the bridge, then run a separate signal ground wire to the pot, etc.
If the pot has a connection from its case to that signal ground, cut it too. You want the signal ground to connect only to the ground at the jack plug.
I corrected years of having a weak signal on my telemutt with this method. Cheers, Mark

[jeremylangford]

Sorry but the things you guys have said seem to be over my head a little bit. I don't know a lot about how pickups work or how grounds and circuits work. This is why I was just trying to follow the tutorial on Guitarnuts for a tele found here



I didn't know exactly why my guitar would stop buzzing, I just wanted to follow the directions exactly and hope that it would work.

All i know is that the tele used in the guitarnuts tutorial doesn't have a screw that is made to screw down into the bottom of the bridge cavity and mine does. All this tells me is that the signal going through my pickup wire is now touching the copper wire that I am shielding with. And if the point of shielding is to stop extra things from hitting the pickup wires, than it seems like I could just be making the problem worse by letting all the things that are in my copper foil touch my sound on my pickup wire.

[pete12345]

Hmm... it seems the wire from the pickup is soldered to another wire, which goes to the jack socket. The screw terminal is, as you suggested, just there to tidy everything up a bit. With it connected to the shielding it will not be protected from electric shock. It won't do any harm in normal use to leave it where it is though.

If you prefer, you can disconnect both wires from the terminal, and solder them together. While you are at it, connect the capacitor (as in the instructions) between the two wires and the screw terminal. Cover the bare wires with insulating tape.

Pete

[ashcatlt]

No.

It's not meant to screw into the bottom of the unshielded pickup cavity. Nor is just there to tidy everything up. It's meant to go around the screw that holds the pickup into the bridge assembly. The same screw you'd use to adjust the pickup height. Normally, it would make contact with the metal bridge itself and act as the string ground as well as the "signal return" for the bridge pickup.

The copper foil and metal bridge which constitute the shielding in this compartment must connect somehow to the rest of the shielding or else you might as well not even have that copper foil in there. That wire accomplishes this whether it's there where you've screwed it down or in its normal placement.

Unless you're installing the safety cap (which isn't mentioned in the Shielding a Tele article) you don't need to change anything.

[jeremylangford]

My wire is already screwed into my bridge pickup. However it is also supposed to screw into the bottom of the bridge cavity.

You say that all the shielding has to be connected but in the guitarnuts tutorial there was no sign of the bridge shielding being connected to any of the other shielding. It says that you do not have to have a new wire in the bridge cavity because the shielding is grounded due to the bridge plate being over it. All I wanted to do was just follow the directions and see if my guitar stopped buzzing. But I don't know what to with my bridge pickup wire because it is made to screw through my copper shielding job and into the bottom of my bridge cavity.

I am very confused and I just want to finish my shielding job so that I can play my guitar again.

Can you explain why it would be okay to have the bridge pickup wire that my sound goes through connected to the copper tape that is supposed to take in excessive radio signals. Why wouldn't this just cause all the excessive signals caught it my copper shielding to go through my bridge wire and out my amp?

[newey]

Jeremy-

I can sense your frustration . But you're overanalyzing this.

If, as you say, this lug was originally screwed into the bottom of the pickup cavity, before you put the copper tape in there, it was screwed into wood, contacting nothing- unless, of course, your cavity already had some shielding in it, maybe shielding paint?

Your photos show that you have run the copper tape up out of the cavity, and onto the face of the body, just as instructed by the Tele shielding mod. This means that your bridge plate will be electrically continuous with the copper tape in the cavity. And the pickup is mounted with metal screws into the bridgeplate.

As Ash told you:

That circle thing is meant to go around the pickup screw at the bridge, and act as "string ground" as well as the signal return for the bridge pickup.

Your confusion is that you are drawing a distinction between the "signal ground" and the shield ground (or 'string ground", as Ash says). But your pickup doesn't have a separate shield connection- the signal return is the shield ground, and vice versa

Ash also said:

That wire accomplishes this whether it's there where you've screwed it down or in its normal placement

Unless you're installing the safety cap (which isn't mentioned in the Shielding a Tele article) you don't need to change anything.

In other words, it just doesn't matter.

[ashcatlt]

Well, I've answered the question. You can leave that wire right there without any detriment.

But apparently, none of us have actually addressed the underlying concern to your satisfaction. I appreciate your desire to understand, rather than just taking it on faith.

I'll leave the real technical details to people who understand it better, but I think I can offer some basic insight.

The whole point of the shielding is to capture the EM radiation and dump it to ground as quickly (and through as little resistance) as possible so that it can't contaminate your pickup signal. The electric guitar has a straight shot to ground by way of the cable which connects the sleeve of its output jack to the sleeve of an amplifiers input jack, which is essentially a direct connection to the ground circuit of the outlet into which the amp is plugged. If the shielding does not connect to this ground via output jack it doesn't have any meaningful shielding effect.

Now, for much the same reason, one side of the pickup also has to be connected to this ground in order for the pickup to work at all. And yes, the pickup does connect to ground through the sleeve of the output jack as well. So "shield ground" and "signal (or pickup) ground" must meet at some point at or before each gets to the output jack, no?

Speaking strickly of noise concerns, it frankly doesn't matter where the two grounds meet. You'll notice that the wire in question goes on from the ring terminal we've been discussing, into the control cavity, and likely to the back of a pot. There it meets several other wires. Tracing these wires you'll find that one of them eventually ends at the sleeve of the output jack.

If you were to unscrew that ring terminal and wrap it in electrical tape, what would be connecting the shielding compartment made up of the copper foil and bridge to the output jack? Jack!

On top of that, it's often (like almost always) considered beneficial to ground out the closest source of EM radiation to the instrument (that's you). That is accomplished when you touch the metal strings, which conduct to the metal bridge, which (when the guitar is wired correctly) conducts eventually to the output jack. In many guitars there would be a seperate wire either soldered or screwed to or kind of wedged under the bridge and running to the control cavity - often to the back of a pot.

In your tele the pickup is right there inside the bridge. It's already got a wire running to ground through the control cavity. Why bother with a second? Just interrupt the wire with a ring terminal, screw that to the bridge, and you're done. I'm convinced that this guitar did not come from the factory with the ring terminal screwed into wood.

Boy, that's a lot of words! Do any of them help clarify the issue for you?

[gitpiddler]

I realize my suggestion wasn't very clear. My point was to keep the ground wire connected to the ring. The black pickup wire should be disconnected from the ring, and extended with another piece of wire thru the hole to the controls, keeping the signal ground away from the shield ground. The trained draftsman in me wants to draw a diagram, but the original tutorial should resemble what I'm describing somewhat IIRC. Sorry about your confusion, hope I can help. Mark

[ashcatlt]

gitpiddler - I, for one, understood your advice. It will work just fine that way. It's uneccessary, though, and really just confusing the issue.

The only good reason to do as you've suggested (to seperate signal ground from shield/bridge ground) would be if he was installing a safety capacitor, as per the QTB instructions as laid out for a Strat. That's not a bad idea.

It has nothing to do with shielding for noise, however. In fact, that cap defeats some of the noise reduction you'd get from shielding by making it impossible for low-frequency signals to pass to ground from the shielding. I guess it's worth noting that even with the safety cap, shield ground and signal ground still must meet at some point (usually right at the capacitor) before leaving the axe.

The Shielding a Tele article only mentions the safety cap in passing. If you follow only the instructions on that page, you won't be adding it. This article assumes that the black wire from the bridge pickup conducts one way or another to the metal bridge plate, which connects to the copper foil in the cavity by way of the little overlap onto the body.

[jeremylangford]

ashcatlt said:

Well, I've answered the question. You can leave that wire right there without any detriment.

But apparently, none of us have actually addressed the underlying concern to your satisfaction. I appreciate your desire to understand, rather than just taking it on faith.

I'll leave the real technical details to people who understand it better, but I think I can offer some basic insight.

The whole point of the shielding is to capture the EM radiation and dump it to ground as quickly (and through as little resistance) as possible so that it can't contaminate your pickup signal. The electric guitar has a straight shot to ground by way of the cable which connects the sleeve of its output jack to the sleeve of an amplifiers input jack, which is essentially a direct connection to the ground circuit of the outlet into which the amp is plugged. If the shielding does not connect to this ground via output jack it doesn't have any meaningful shielding effect.

Now, for much the same reason, one side of the pickup also has to be connected to this ground in order for the pickup to work at all. And yes, the pickup does connect to ground through the sleeve of the output jack as well. So "shield ground" and "signal (or pickup) ground" must meet at some point at or before each gets to the output jack, no?

Speaking strickly of noise concerns, it frankly doesn't matter where the two grounds meet. You'll notice that the wire in question goes on from the ring terminal we've been discussing, into the control cavity, and likely to the back of a pot. There it meets several other wires. Tracing these wires you'll find that one of them eventually ends at the sleeve of the output jack.

If you were to unscrew that ring terminal and wrap it in electrical tape, what would be connecting the shielding compartment made up of the copper foil and bridge to the output jack? Jack!

On top of that, it's often (like almost always) considered beneficial to ground out the closest source of EM radiation to the instrument (that's you). That is accomplished when you touch the metal strings, which conduct to the metal bridge, which (when the guitar is wired correctly) conducts eventually to the output jack. In many guitars there would be a seperate wire either soldered or screwed to or kind of wedged under the bridge and running to the control cavity - often to the back of a pot.

In your tele the pickup is right there inside the bridge. It's already got a wire running to ground through the control cavity. Why bother with a second? Just interrupt the wire with a ring terminal, screw that to the bridge, and you're done. I'm convinced that this guitar did not come from the factory with the ring terminal screwed into wood.

Boy, that's a lot of words! Do any of them help clarify the issue for you?

Ok. I think Im finally starting to understand what you guys are saying. But really, I can assure you that my gutar was made with the black pickup wire screwed into the wood into the bottom of the cavity. However, there is another one of those rings that is screwed into my pickup, achieving what ashcatlt was saying that the rings on the wire were made to do. My guitar just happened to have 2 of those rings, one on the pickup, and one in the wood.

[newey]

Jeremy-

But really, I can assure you that my gutar was made with the black pickup wire screwed into the wood into the bottom of the cavity

No one's doubting what you're seeing with your own two eyes. We're doubting that it's stock in that configuration.

As I said above, that would only make sense if there was some cavity shielding in there to begin with, before your copper-tape job.