Cobain Jaguar Wiring Questions

[AbramT80]

Making my first guitar, started a few weeks ago, it's a jaguar model with matching electronics to Cobain's jag. This is a little embarrassing and probably dumb but I've got absolutely zero experience soldering or doing anything with circuitry and I've decided to do electronics on my own. I'm following a really detailed diagram so most of it shouldn't be too hard. I've just got a couple questions. On the bridge pickup it has a wire that says "ground lug to control cavity" then on the same wire, "black wire to bridge" and I'm not sure what that means and can't find much about it online. Then on then neck pickup it's got 3 wires coming out of it, two soldered to eachother and the other goes to the bracket that holds the electronics for the rhythm circuit (mind you not on the electronics but on the bracket holding the electronics), on the other end of the bracket, there's a cap that connects to one of the pots. Am I reading the diagram correctly? Thanks, please advise.

[Bizman62]

First of all, welcome!

1 hour ago, AbramT80 said:

On the bridge pickup it has a wire that says "ground lug to control cavity" then on the same wire, "black wire to bridge" and I'm not sure what that means

That's pretty straightforward: The cap of the pot is a gathering point for ground. As you may or may not know, you'll have to ground the strings through the bridge so that when you touch a string you'll eliminate most of the buzz. The lug is just for fastening, actually this is the first time I ever see one! If there's metal tape inside the cavity it makes more sense. A wire going from the pot to the bridge does the trick as well.

 

1 hour ago, AbramT80 said:

Then on then neck pickup it's got 3 wires coming out of it, two soldered to eachother

That's because they're humbuckers that actually have two coils inside them. The wires could as well be hidden inside the cover but they're visible just in case someone wants to separate them for more options.

 

1 hour ago, AbramT80 said:

the other goes to the bracket that holds the electronics for the rhythm circuit

To me that sounds like a grounding wire. Even more so if there's metal foil on the pickguard, connecting all components to ground.

1 hour ago, AbramT80 said:

there's a cap that connects to one of the pots.

Again, the top of the pot acts as a ground - you can see one of the lugs soldered to the top of both volume pots, in the tone pot you add the capacitor to cut only the higher frequencies off.

[AbramT80]

1. So just for the sake of my own knowledge of this guitar, on the neck pickup, sending a wire and pot through the same bracket will produce a signal? Even if no wires from the pickup go directly to a component?
2. Also, just to be clear on the3 ways switch, I can go straight from grounding it on the pot to bridge? Is it necessary to ground it to a shielded cavity?
3. Last question, how can I tell which wires go where coming out of the pickups? Because the one's I've ordered of course don't match the colors of the diagram
4. Thanks for the welcome and super thank you for all the advice, very helpful

[Bizman62]

1. Umm... I'm not sure I understand what you mean here... But let's start with the most simple thing: There's basically two wires in a pickup, the hot and the ground. The hot goes to the lug of the jack that touches the tip of the plug and the ground go to the lug that connects to the sleeve of the plug. That's the most simple wiring, sort of a loop going from your amp through the pickup and going back to the amp. All the pots and caps follow that path as part of the loop, switches just provide an alternative path.

2. There's quite a lot of misinformation about grounding. In all simplicity the sleeve lug of the jack is the final grounding spot. How each wire is connected to that spot depends on how neatly you want to build. There can be a solid metal plate inside the cavity as a common grounding spot or rather area that connects the outside of all pots and switches and even pickup grounding wires, and the bridge wire as well, or you can choose one pot as a grounding spot and connect all other pots and other components to that spot and finally to the jack. I've seen bare stiff wire running from pot top to pot top, neatly grounding each of them... As said, all is well if all is grounded to the jack one way or another.

3. The colour coding of pickups can be confusing. Often there's a braid right under the shielding. That's for ground. The two ones soldered and shrink tubed are "hot", continuing the loop described in 1. A colour-colour is usually the "hot" and the other one (often black or white) is then the ground. Yes, double ground, the braided wire grounds the cover of the pickup and the inner ground is for the signal. 

There's much more advanced electricians here than I am and hopefully they'll chime in soon, but that's how I've managed to follow the diagrams.

[AbramT80]

Thanks, I appreciate it

 

[curtisa]

7 hours ago, AbramT80 said:

On the bridge pickup it has a wire that says "ground lug to control cavity" then on the same wire, "black wire to bridge" and I'm not sure what that means and can't find much about it online.

The 'ground lug to control cavity' attaches to a conductive section of the control cavity. This could be shielding paint or foil tape. It's used to allow the shielding of the guitar to be grounded to act as...well, a shield... to incoming radiated electrical noise (hums, buzzes, radio interference etc).

The 'black wire to bridge' attaches to some metallic component of the guitar bridge itself, but it is primarily intended to ground the strings. So whatever part of the bridge you choose to connect it to, it needs to be conductive all the way through. I'm not familiar with the Jaguar, but I see references online that if you're using the original Jaguar tremolo the grounding point is actually one of the bridge 'thimbles'. 

 

5 hours ago, AbramT80 said:

So just for the sake of my own knowledge of this guitar, on the neck pickup, sending a wire and pot through the same bracket will produce a signal? Even if no wires from the pickup go directly to a component?

The black pickup wire to the bracket on the rhythm circuit is providing a ground connection to the neck pickup, and does not act as a path for your signal as such. You'll notice there's a lug shown on the lower-right of the slide switch with a wire leaving it, going to the 3-way toggle, and from there to the back of the Volume 2 pot. That's part of your ground circuit. The white wire on the neck pickup going to the lower-middle lug of the slide switch is your signal output from that pickup.

 

5 hours ago, AbramT80 said:

Also, just to be clear on the3 ways switch, I can go straight from grounding it on the pot to bridge? Is it necessary to ground it to a shielded cavity?

By and large ground can go any which way you like in a guitar, as long as every point in the circuit that needs to be grounded is grounded. The wiring path you choose to take is entirely up to you, but mostly limited by the practicality of executing the wiring. It's easier to attach one wire to the bridge as a grounding point than to attach half a dozen. 

However for ease of construction I'd advocate you follow the diagram as faithfully to the original as possible, especially if this is your first time doing it. It will make it easier to debug if something doesn't work after you finish wiring it all up.

 

5 hours ago, AbramT80 said:

Last question, how can I tell which wires go where coming out of the pickups? Because the one's I've ordered of course don't match the colors of the diagram

What pickups did you order? Maybe the manufacturer has a wiring colour code?

 

3 hours ago, Bizman62 said:

A colour-colour is usually the "hot" and the other one (often black or white) is then the ground.

No. The colour scheme chosen for pickup wiring is entirely arbitrary, and the colour-ness of the wire has no bearing on its function. It's only used to differentiate each of the wires to make it easier for people to identify each core for assembly. Historically (and probably still today) wiring anything on an assembly line was done by non-skilled labour who didn't need to know how the circuit worked to put it together. They just needed to follow the wiring diagram put in front of them to know that the red wire went to left lug of the 3-way switch.

As pickup wiring has never been standardised we're left with the situation that manufacturer's can choose any colour they like for their pickups, hence the messy scenario where wiring diagrams available online specify particular wiring colours in certain locations using a particular branded pickup. The end user then has to translate this wiring code if they choose to install a different pickup.

Related note - the neck pickup wiring shown in the original diagram at the top of this page seems unusual. Notice how the red/green are paired, black is ground and white is hot? This differs from the bridge pickup wiring which shows white/black paired, green as ground and red as hot, which also matches Dimarzio's wiring recommendations for their pickups. Maybe this is deliberate and was how Kurt had his Jaguar wired, but seems a little odd on first glance at the diagram.

[Bizman62]

9 hours ago, curtisa said:

The colour scheme chosen for pickup wiring is entirely arbitrary, and the colour-ness of the wire has no bearing on its function.

Thanks for reminding. I actually had to check the wiring of a couple of pickup sets I have here and to my embarrassment white was used as hot on both sets. Dare I still say that if black is the only common nominator in a set of pickups of the same brand, it most likely is ground?

[henrim]

Better not to assume. In the above drawing DiMarzio pickups are used and in their color coding green is ground (+bare shield wire which above picture omits).

I didn’t know what pickups were used in the Jaguar in question so I googled. If the first Google result was right they are PAF 36th and Super Distortion. Common pair and the very same that is in my current build. The two, like all the other DiMarzio pickups I know, have the same wiring. So in the above picture is the neck pickup is wired backwards for some reason. Sound reasons I guess.

Unrelated but a little bit related. I have to say I hate these spaghetti drawings. So much easier to read a regular schematic drawing.

[curtisa]

1 hour ago, henrim said:

In the above drawing DiMarzio pickups are used and in their color coding green is ground (+bare shield wire which above picture omits)

Yes and no. There's nothing that says green has to be ground as per Dimarzio's wiring colours. It's just conveniently drawn that way to make it somewhat standardised within the Dimarzio universe. You can also ground red, make green hot and the pickup would still work, just with reverse phase. Do it to both neck and bridge pickups and you'd never be able to tell the difference from wiring both pickups with Dimarzio's original red hot/green ground recommendations - they'd sound exactly the same.

Going back to the original wiring diagram, the neck pickup will work as drawn, it's just that the two coils are 'stacked' upside down compared to the bridge pickup. It's still humbucking; I just have no idea why Fender would go to that length to wire the neck pickup that way. Maybe they're just trying to be historically accurate to Kurt's original Jaguar, and perhaps it was always wired that way whether by accident or design.

 

1 hour ago, henrim said:

I have to say I hate these spaghetti drawings. So much easier to read a regular schematic drawing.

Schematics and wiring diagrams serve different purposes. A schematic tells you how the circuit works. A wiring diagram tells you how to put it together. From a circuit analysis perspective, like you I also prefer a schematic so I can see what the controls and components actually do in the guitar. But a wiring diagram is more accessible to builders just wanting to get a new wiring layout up and running, and so remains the de facto norm in guitar building. 

[henrim]

18 minutes ago, curtisa said:

There's nothing that says green has to be ground as

No there isn’t. Good that you pointed it out because now that I read what I wrote  it wasn’t really clearly written. I just meant to say that in Dimarzio notation green is (usually) used as ground. Their site has plenty wiring diagrams and there are obviously out of phase configurations there too. 

30 minutes ago, curtisa said:

But a wiring diagram is more accessible to builders just wanting to get a new wiring layout

Guess you’re right. To me a wire diagram makes a fairly simple circuit look more complex than it is. But yes, if you are soldering from point to point without trying to understand what is happening in the circuit, it’s quite likely easier to follow. 

[Bizman62]

2 hours ago, henrim said:

. But yes, if you are soldering from point to point without trying to understand what is happening in the circuit, it’s quite likely easier to follow. 

For me it's exactly that. Schematics are Greek to me.

[AbramT80]

16 hours ago, curtisa said:

What pickups did you order? Maybe the manufacturer has a wiring colour code?

I ordered exactly what was listed in the parts section:  a DP100 super distortion for the bridge and  PAF 36th Anniversary for the neck. I looked on the Dimarzio site but couldn't find too much about their specific color codes, it was more general information about color codes as a concept.

[henrim]

22 hours ago, AbramT80 said:

Last question, how can I tell which wires go where coming out of the pickups? Because the one's I've ordered of course don't match the colors of the diagram

 

47 minutes ago, AbramT80 said:

I ordered exactly what was listed in the parts section:  a DP100 super distortion for the bridge and  PAF 36th Anniversary for the neck.

Red, Green, Black, White and bare, braided shielding cable. Bare is not drawn in the above diagram but it is supposed to be tied to ground. Otherwise I think the colors should match the diagram. In the drawing neck pickup's red and green are tied together. On the bridge pickup black and white are tied together. I would be surprised if Dimarzio has changed their colour coding.

Please note on the tone potentiometer 1 that the capacitor leg coming from the potentiometer lug should be insulated. If soldered as drawn. There is actually insulation in the drawing but it's not really clearly marked.

[AbramT80]

1 hour ago, henrim said:

Please note on the tone potentiometer 1 that the capacitor leg coming from the potentiometer lug should be insulated. If soldered as drawn. There is actually insulation in the drawing but it's not really clearly marked.

I'm very new to all of this circuitry and electronics, how do I insulate it?

[henrim]

17 minutes ago, AbramT80 said:

I'm very new to all of this circuitry and electronics, how do I insulate it?

You can use for example a piece of insulation you strip off a wire. Or use shrinking tube. The point is that both legs of the capacitor cannot touch the potentiometer case (ground). I just wanted to point it out because when I first looked at the drawing I didn’t notice the insulation on the leg and I was puzzled what’s going on.

[henrim]

You can also solder it so that it doesn’t touch the case but there is a risk it gets shorted to ground at some point. I would insulate. 

[Bizman62]

1 hour ago, AbramT80 said:

how do I insulate it?

Even a piece of tape (electrician's tape is better than Scotch Magic) between the leg soldered to the lug and the case will do, or a piece of tape wrapped around said leg.

[henrim]

24 minutes ago, Bizman62 said:

tape

Yeah, that or even hot glue in this particular instance. I just always forget these as they are forbidden in my shop

[curtisa]

7 hours ago, AbramT80 said:

I ordered exactly what was listed in the parts section:  a DP100 super distortion for the bridge and  PAF 36th Anniversary for the neck.

Can you describe how the wire colours on the pickups you ordered differ from the ones shown in the diagram? As @henrim indicates, they should be a match if they're both Dimarzio's.

[AbramT80]

On 1/31/2023 at 7:43 AM, henrim said:

 

Red, Green, Black, White and bare, braided shielding cable. Bare is not drawn in the above diagram but it is supposed to be tied to ground. 

So I've got the pickups now, they match the colors on the diagram but have an extra wire (the uncolored, braided one). does it matter where I ground that to? Is there a standard or safe place to ground it to? Any places to definitely NOT ground it to?

On 1/31/2023 at 7:43 AM, henrim said:

Please note on the tone potentiometer 1 that the capacitor leg coming from the potentiometer lug should be insulated. If soldered as drawn. There is actually insulation in the drawing but it's not really clearly marked.

So I solder it then insulate it? And on the second tone knob, it's grounded to the pot itself right? Not the bracket holding the pots?

[Bizman62]

18 minutes ago, AbramT80 said:

does it matter where I ground that to? Is there a standard or safe place to ground it to?

"Ground" is basically an extension of the sleeve lug of the jack. It can be a metal plate covering the bottom of the cavity, a cobweb of wires, even the copper tape glued into the cavity.

A commonly used place for a gathering point for ground is the top of one of the capacitors. A knurled washer screwed in a convenient place works equally well. Thus you can ground the braided wire anywhere as long as the path finally takes to the ground (sleeve) lug of the jack.

27 minutes ago, AbramT80 said:

So I solder it then insulate it?

Rather the other way around especially if you're going to use a plastic tube for insulation. Leave bare just the length you need for soldering.

33 minutes ago, AbramT80 said:

on the second tone knob, it's grounded to the pot itself right? Not the bracket holding the pots?

As previously said, all ground is the same. On the second tone knob the capacitor goes from lug to top (ground) similarly to Tone 1. A potentiometre is basically an adjustable ground which you can further adjust with a capacitor. "Partially grounded" isn't necessarily a correct term but that's what a pot does.

[AbramT80]

28 minutes ago, Bizman62 said:

Rather the other way around especially if you're going to use a plastic tube for insulation. Leave bare just the length you need for soldering.

So I'm just insulating to keep it from shorting out?

[Bizman62]

Exactly.

The weirdest short to sort out I've had so far was with my Strat: I had put shielding tape into the jack cavity and every time I put the plug in the prong touched the tape. At first I of course thought about a bad solder joint so I took the boat out for checking. No problems when the jack wasn't seated! Even when it was loosely seated it worked but when tightened all sound was lost. Another similar issue with a Strat boat was with the attaching screw: The screw was long enough to touch the tip when fully tightened. Fun times trying to find the culprit!

[AbramT80]

Getting ready to order wires to connect everything up but I’m not sure what gauge wire to use or how to find out. Also for the on-on switch, do I need to buy a switch specifically for guitar or will any on-on switch work as long as it’s the same layout and dimensions?

[curtisa]

1 hour ago, AbramT80 said:

I’m not sure what gauge wire to use or how to find out

Buy whatever wire you can get your hands on that is still easy to work with - there's nothing magical about guitar-centric brands or buzzwords. AWG 18 - 22 is perfectly OK. Avoid solid core wire, stick to stranded. You may be able to get wire for free if you re-purpose something that is being thrown away - say the power lead from an old broken plugpack.

 

1 hour ago, AbramT80 said:

do I need to buy a switch specifically for guitar or will any on-on switch work as long as it’s the same layout and dimensions?

I assume you mean the little slide switch on the upper horn? Again, whatever works both physically (does it fit the hole in the guitar?) and electrically (does it have the right number of contacts and do the right thing when you operate it?). Your only real concern then should be about spending money on a switch that is robust enough to go the distance.