The Black Strat. Circuit wiring – Part 1. Pots and switches.

Wiring a guitar is really just a process of connecting up the right bits, in the right order. Once you get the hang of soldering, it’s easy to do, and putting a guitar circuit together can be quite a relaxing, and rewarding, experience. Take your time, and plan your layout – and you can do it all in a manner which makes it look like you might know what you’re doing.

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The circuit for the Black Strat will be based on a classic Stratocaster wiring schematic, which has stayed pretty much the same since the Strat was first put together, back in the early 1950’s. Obviously – this example will have the famous “Gilmour Modification”, to enable the independent neck/bridge switching function – but that’s a modification which effectively sits on top of the standard Stratocaster foundation. Now this is still one of the first, few guitars I’ve ever wired – so I don’t claim to be an expert in any this – but I’ve found it’s easy to pick up the basics, and once someone has shown you round the circuit – it’s easy to replicate in a reasonably professional looking manner. When it came to picking up the basics – I took advantage of the videos available on Six String Supplies’ own YouTube channel. They’re super clear, and easy to follow. With a little extra reference study – to find out what the various bits and pieces do – the circuit begins to make sense.

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I’ve already fitted the pots and switches onto the scratchplate. Now I can begin to build the circuit by wiring up the main, interconnecting wires between each of the components. Soldering can be fiddly – so I lay the scratchplate, upside-down, on an old offcut of oak worktop I had kicking around. With some holes drilled in the right places, it’s possible to lay the scratchplate flat and secure onto the board – so that it’s held firmly in place. Part of the knack of soldering, is getting things to stay in place while you find three hands to do it with. You really don’t need to occupy one of your hands by holding the plate down. Personally, I also find it helpful to have a close tasklight over the area and, since the solder can give off some noxious fumes, it helps if you have some ventilation too. I try and do most of my soldering on the kitchen hob – with the kitchen extract on.

To explain the process, I find it useful to identify the various contact points in the circuit, and to give them individual designations. Then the wiring can be broken down into a simple series of point to point connections. If you keep the soldering tidy, and run your wires logically and tidily – then the end result should look good, and perform properly. The photo above shows the designations I use for wiring a Strat. With the plate lying in the position shown, the top row of contacts, on the far side of the selector switch are numbered, left to right, S1 to S4. The contacts on the near side of the switch are numbered, again left to right, S5 to S8. The micro switch has three poles and they are designated – left to right – G1 to G3, (although I’ll not be hooking these up until later). The tone pot contacts are numbered top to bottom, from my viewpoint. The first tone pot, TA1 to TA3 – and the second, TB1 to TB3. The volume pot contacts are similarly numbered V1 to V3.

The first thing to do, is to heat up the soldering iron to operating temperature. It always helps, when soldering, to keep the tip of the iron clean. So I try to wipe it on a little bit of damp foam, and also scrape off any excess bits of solder on some brass shavings, as I go along. I also use a solder with a fluxed core. I hear silver solder is supposed to be best – but I find it hard to get hold of and I just tend to use the best I can find at the local hardware store. Once the iron is hot, I start by tinning all of the contacts that will be connected. Quite simply, this makes the task much simpler. All I do is heat each contact in turn with the tip of the iron, and then melt just a little solder around the opening of each contact. The tip of the iron should be enough to heat up the contact enough, so that you shouldn’t have to actually touch the solder with the iron. Just drawing round each opening as the solder melts, does the trick. For a standard Stratocaster wiring job – all the contacts need to be tinned, except S7, TA1 and TB3.

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There seems to be plenty of opinion and debate around just how to ground the guitar circuit. In most schematics, most of the circuit ground wires are soldered back to the volume pot – and consequently, the back of the volume pot usually has a confusing tangle of wires, all soldered to the back. Since I’ve taken the time to copper line the interior routs of the guitar body, and installed a central grounding point – it makes sense to run all my grounds to that, central point. I’ve already installed a small lug screw in the wall of the main control cavity, and connected up a grounding wire running from the tremolo claw. It makes sense to me, to run a similar, lugged fly lead from the pots. I’ll still connect the pickups to the circuit on the back of the volume pot, as is traditional – but I ultimately want to run all of the grounds to that same, central, point.

Most schematics show grounding wires connected between the metal bodies of the three main pots. There’s also another wire shown which connects the back of the volume pot to the ground terminal of the output jack. Since my ground will run, instead, to the central grounding point, (where it will meet the jack ground), I begin by attaching a screw lug to a piece of black, cloth covered wire. I use single core stuff for this particular task. I find it’s a bit sturdier than the twisted wire type. The wire which joins the pots is sometimes left as an un-insulated, single piece of wire, but here I’m using cloth insulated wire – and just nicking the covering to allow the wire to show through at the right points. That way, I can take a single piece of wire, beginning at the second tone pot – joining the first tone pot, the volume pot, and then running it on a little, to end with the soldered lug at the end of a fly lead. When it finally comes to installing the plate – I can simply hook up this running ground wire to the grounding point, solder the “hot” connection from the jack socket, (to contact V2), and then screw the plate down. Job done.

Another bit of preliminary grounding work, is to connect the contact V3 to the back of the volume pot itself. Sometimes this is done with a separate grounding wire – but it’s much easier to bend the actual tab back against the casing of the pot, and to secure it there with a dollop of solder. It helps to tin the back of the pot in the right spot first, and then to push the contact down, against the back of the pot with the iron, whilst flowing a little more solder. This forms a good, efficient connection.

I use a black, cloth covered wire for all of the grounding work – but for the rest of the signal path, I switch to another, again traditional, white or cream coloured wire. The circuit is built, and is a simple task of connecting the correct pairs of contacts. The challenge, and part of the satisfaction of doing it yourself – is to make the wire runs tidy and efficient. Of course – you could always try and use short, direct, point to point connections – but things can quickly get untidy. Routing the wires carefully can help keep enough room around each of the contacts, to make subsequent connections (and repairs) easier. And careful routeing, which is loose enough, will always help guard against things coming adrift over time – causing problems. The following connections are all routed, with wires of adequate length, and with good solder joints at the connecting points.

First, a jumper wire is set between S1 and S8. Keeping this wire in a loop, down the side of the switch, helps route the wire away from the other switch contacts. Before the S8 connection is soldered, a second wire is run to connect S8 with V1, on the volume pot.

Next, wires are routed and soldered between S5 and TB1, and from S4 to TA2. Bending the pot contacts up into more of a perpendicular position, helps to make a bit more room to get your fingers in there.

And that’s pretty much the basics of the switching side of the Stratocaster circuit. The only thing left to do before getting involved in the next stage, with the pickups – is to fix the tone capacitor in place, on the back of the first tone pot. The wiring kit has an 0.047uf  “Orange Drop” capacitor, but I’ll be using a different option.

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The tone capacitor is an important part of the guitar circuit – especially for single coil pickups – where some of the harsh brightness of the tone is controlled by the addition of this capacitor. Different capacitor values have a slightly different effect on the overall tone of the guitar – with the typical value employed by Fender, changing over the years. This change has a great deal to do with the evolution and subtle differences between the tones of – say – a 1950’s vintage Stratocaster, and a 1970’s example.

For a 1969 circuit – which Gilmour’s original guitar started out with – a capacitor value of 0.047uf is appropriate – but the technology was slightly different at that time, and the capacitors were constructed in a slightly different way than most of the ones used today. Now there’s huge debate about the actual difference any of this makes – but since I’ve taken the option of sourcing the exact pickup combination for this tribute build – I might as well try to match the tone capacitor as best I can. The thing is – original examples of the right capacitor are virtually impossible to find, and when they are – they’re stupidly expensive. Not suprisingly – for those wanting to upgrade their guitars, or those looking for an exact duplication of detail – someone saw a gap in the market.

Luxe capacitors are detail accurate, and functionally correct copies of original, vintage parts. They are sold as being, “fresh from the time machine”, and are actually specification correct, modern analogues of original parts – apparently with the modern, identifying markings erased, and period-correct details screenprinted in their place. The end result is a stupidly indulgent piece of kit – where the packaging appears to be as important as the actual item. The capacitor comes with it’s own little velvet bag, and is presented in a cardboard mock up of a traditional, Fender Tweed case. There’s also a Luxe sticker, and an interesting flyer detailing period correct installations of the various components Luxe now produce. For the money – I presume they are dipped in unicorn tears before packaging. They’re currently impossible to get hold of in the UK, and I had to get the 1969 “Orange Dime” example for my circuit, shipped in from Germany.

In all honesty – the Orange Drop probably would have sufficed. Orange Drops themselves are already considered a pretty good upgrade from some of the usual, modern stock components. However, since this project is all about trying to build with the the best quality components I can afford – and since the capacitor, working in tandem with the specially purchased pickups, will have much to do with the eventual tone of the guitar – I might as well go for Luxe quality, and hope for the authenticity of tone that’s promised – as indulgent as it may be.

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The capacitor sits on the back of the first tone pot, and the legs are trimmed and bent to shape, so that the right hand leg is short enough to ground onto the back of the tone pot itself. The left hand leg is threaded through connection TA3, and then run on to TB2. The capacitor comes with a, period correct, bit of yellow tubing to cover the leg until it gets to TA3. This stops the capacitor shorting onto the back of the pot, and the yellow tube provided, just needs trimming down slightly for this installation. Once the two connections are soldered – the capacitor is firmly in place, and the basic wiring of the switches and pots is complete.

Sometimes, the circuit is modified with a jumper wire between S5 and S6. This brings the tone pot into the circuit for the bridge pickup also. (Normally, ony the neck and middle pickups are controlled by the tone pots). A further modification is sometimes found with the installation of a “Treble Bleed” component. However – since neither of these mods is on Gilmour’s original Black Strat – I’ll leave the options open for now. If I ever decide to add them in, for any reason, it’ll be a simple upgrade – made for distinct, personal adjustments to overall tone and performance above the original specification.

The next stage will be to install the actual pickups, and to integrate their wiring into the overall circuit.

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