All posts by Anthony Partridge

02Oct/15
Ironstone-Guitar-Pickup-Tester

Guitar Pickup Tester (Part 1)

Guitar Pickup Tester (part 1):

Without a dedicated guitar pickup tester, it only takes a few days experimenting with guitars and pickups before you realise that it can be quite a slow process. Telecasters, LPs and many other guitars at least allow easy access to the control circuitry. But of course a Strat needs a full de-string to achieve even that. And when it comes to changing and comparing pickups, things get even more time consuming, whichever model you mention. 
So at Ironstone we have a number of guitar pickup tester rigs specifically to speed up or enhance testing, experimenting and general guitar related fun.
Hopefully some of these will give you ideas that you can use, they need no more than the sort of guitar parts or cheap donor guitars that many will have lying around. 
Part 1 of this blog features a simple, yet highly modified guitar used for ultra-swift pickup installation and testing.
The first tester featured looks pretty normal from the front, a typical Strat copy.
Ironstone Guitar Pickup Tester
But viewed from the back things are somewhat different.
Ironstone Guitar Pickup Tester
A 'swimming pool' style body routing is a great start for many test style guitars, but this one goes further, with the entire centre section routed out (and the trem blocked to make it a static installation). The picture shows the silver foil covered underside of the top scratchplate, with the pickups simply pushed through the mounting slots. Small felt pads give a workable height setting between the top of the pickups and strings. The electrical connections to the pickups are via the croc clips, which are themselves hard wired back to the scratchplate electrics.
Ironstone Guitar Pickup TesterThe pickups are held in place by 2 slabs of foam. The first one simply presses the pickups into place, and allows the croc connections to be made away from the conductive foil scratchplate covering.
Finally, a second block of foam holds all of the croc clip connections securely, and applys a little more pressure to the pickup mounting.
Ironstone Guitar Pickup Tester
Once this is in place, the tension of the slightly over-sized foam blocks holds everything quite firmly in place. The guitar is now fully playable without a full de / re-string.
In fact the time from start to a complete new set of pups in place and ready to play is no more than 2 minutes - perfect!
There are plenty of variations on this theme of course, and hopefully this example will get your creative juices flowing!
The next blogs in this series will feature a scratchplate tester and our most complex multi switcher Strat. Plenty for the enthusiastic guitar pickup tester to enjoy!
For a few more ideas and commercially available options, check these out;
https://www.youtube.com/watch?v=yZZkvvWMz3A
http://www.lundgren.se/about/mick-testgitarr-pa-vit-duk/

 

30Sep/15
Stratocaster Scratchplate Pickguard Troubleshooting

Stratocaster Scratchplate Troubleshooting

Stratocaster Scratchplate Pickguard Troubleshooting:

Brilliant design as the Stratocaster is, having to de-string and remove the scratchplate / pickguard to work on the electrics can be a real frustration. So this Stratocaster scratchplate pickguard troubleshooting guide focuses on what you can do before you even lift the plate!
Whilst focussing on the Strat, many of these tips apply to all guitar types.
Things that can go wrong. 
Let's start by considering what might go wrong. Guitar pickups themselves have 2 likely failure modes; open and short circuit. By far the more common of the two is open circuit, typically a break in the hair thickness winding wire. This renders that particular pickup dead, but does not prevent the operation of other pickups.  Less common is the pickup going short-circuit (i.e. measuring zero Ohms with a multi-meter) to the guitar's earth. This could be caused by a stray whisker of wire shorting between the two pickup connection eyelets for example.
Then there is the actual wiring within the guitar itself. Again simplest described, poor construction could lead to wires breaking or losing electrical contact, or shorting across other contacts. Whilst things like a faulty tone capacitor can of course also occur, the steps below will capture the majority of Stratocaster scratchplate troubleshooting issue.
Tests without a Multimeter.
We can begin with nothing more than a screw driver - 'tap testing'. Connect your guitar to an amplifier / speaker and set the volume on the guitar and amp lower than normal. Select (say) the Bridge pickup and gently tap its pole pieces with the screwdriver. A distinct 'thump' should be audible. Just as importantly, no sound at all should come from the other two pickups with just the Bridge pup selected.
No thump shows a problem with that pickup.
Repeat this for all 5 way switch positions. This is also a very useful test to do on Strat after wiring work but before the effort of re-stringing. In this way, even tone controls can be checked with no strings in place, as the tone of the 'thump' will be noticeably different moving from full treble cut to no cut.
Tests with a Multimeter
So here is where it gets interesting. With the scratchplate still in place, connect a normal guitar lead to the guitar. Connect a Multimeter on a resistance range appropriate for your pickups resistance (20kOhm is a common range) and attach the 2 meter leads to the open jack plug; one connection to the jack tip, one to the jack 'body'.
Now get the guitar volume and tone controls to maximum '10'. Select the Bridge pickup on the 5 way switch. Correct to a couple of hundred Ohms, you will now see the Bridge pickups resistance whilst it is connected 'in-circuit'. The same will be true when you select the Middle or Neck pickups.
Stratocaster scratchplate troubleshooting
The in-between 5 way switch positions 2 and 4 put two Strat pickups in parallel, so you would expect to see resistance readings of approximately half the 2 pickups being combined (e.g. for standard 6kOhm pickups a combined reading of 3kOhm). If a single pickup has gone open circuit, you will get an open circuit reading for it, and its related position 2 or 4 reading will be the normal reading of the adjacent working pickup (e.g. 6kOhm in our examples). If its gone short circuit (zero resistance) that is what you see for the pickup itself and the related position 2 or 4.
You can even 'see' from its resistance a pickup in operation. Connect a Multimeter as described and select a pickup. Now do the 'tap test' from earlier on the selected pickup but without the amplifier etc. You will see the resistance reading of the pickup jump around by plus or minus several kOhm.
So without even having taken any screws out (or even without strings in place), its possible to get a lot of information about the health and specification of your pickups and general wiring. Stratocaster scratchplate pickguard troubleshooting has never been so simple!
Because you are measuring effectively the resistance between the guitar's ground and the output 'wiper' of the volume potentiometer, its even possible to get a sense of any problems there. Regardless of its value (e.g. 250 / 500kOhm), sweeping the volume pot from full volume to no volume (10 to 1 on a Strat) will result in a resistance reading from the value of the pickup(s) selected at full volume to zero Ohms at lowest volume. Note, the resistance seen in the middle of the volume control's travel will be a rather odd seeming value (60kOhm or so) as the low pickup resistance and (relatively) high volume potentiometer resistance interact.
Its worth also saying that a faulty 5 way switch (pretty rare in our experience), may give similar results to a faulty pickup(s). Sadly there is no way of getting a definitive answer without physically disconnecting the pickups and measuring them individually.

 

Conclusion.
Stratocaster scratchplate pickguard troubleshooting naturally may need to go beyond what I have outlined already, and of course once you find a problem, physically repairing it will need the scratchplate to be removed. But at least the diagnosis can be done simply and quickly.
Earthing problems are of course another topic altogether, and I have put some other links below to start to address those.

 

02Sep/15
single coil pickup dummy coil

Single Coil Pickup Dummy Coil

Single Coil Pickup Dummy Coil:

Any single coil pickup does just that. It uses a single (rather than multiple) multi-turn (e.g. 8000) coil of wire to sense the movement of metal (i.e. guitar strings) in its vicinity. That's great and gives the single coil characteristic tone we all know and love. But sadly, the same physical construction also does a pretty good job of picking up a range of definitely unwanted electrical noise that the pickup interprets as signal. Sadly us humans detect that as noise not signal! A single coil pickup dummy coil may just be the answer.
Types of electrical noise. 
First off its worth spending a moment making a sub division here. Not all guitar noise is the same.
To keep things simple, unwanted guitar noise can be split into 2 categories; hum and buzz are pretty commonly used terms. 
Hum is linked to magnetic fields created by mains power circuitry. As such, its dominated by the frequency of the mains electrical system (50Hz here in the UK, 60Hz in N. America for example).
Buzz is much more varied in its source, but can be categorised as a 'transmitted' source and sounds more like static. So in the basket of buzz sources, you find everything from fluorescent lights, electrical power tools and anything with higher frequency electrical switching going on.
Single Coil noise reduction basics.
So lets dig into the basic single coil pickup design a little more. As mentioned its simply a large number of fine wire windings wound around a magnetic arrangement, either as pole pieces or a bar. Its the combination of the magnet(s) and the coil that allows a single coil pickup to sense movement of metal close to it. Putting it another way, the coils alone (without magnets) would not sense that movement (or at least at a hugely reduced level). There are quite a few designs that use different construction, but this article sticks to conventional single coils. For more explanation of single coil and humbucker designs, check out the Ironstone page;
Electric Guitar Pickups Explained
Quieting the Single Coil beast! 
So there are 2 main strategies for removing noise from a single coil pickup, shielding and cancelling. 
Shielding is normally an effective way of minimising Buzz, but it cannot effectively remove Hum. To do that a single coil pickup dummy coil is an effective solution.
For information on shielding see;
Electric Guitar shielding
So coming back to noise cancelling, this simply means adding an electrical signal containing unwanted noise to another signal containing the 'negative' or 'inverse' of that same noise. The theoretical outcome is that the positive and negative electrical representations of the same noise cancel each other out leaving just the pure (wanted) signal from the vibrating guitar strings. This cancelling (or 'bucking') of the hum is the principle of the humbucker design. That's simply 2 single coils, mounted as close together as possible and each one wound and magnetically aligned opposite to the other. That 'opposite' arrangement is what generates the positive and negative versions of any common noise the humbucker pair is sensitive too. So the humbucker is a very elegant hum cancelling solution, but the tonal characteristic is of course very different to that of a single coil.
Just to complete the picture, a move to active pickups is a way of eradicating both Hum and Buzz. The same is true of 'Noiseless' pickups (effectively humbucker variants), but neither convincingly recreate that single coil tone.
Enter the dummy coil.
So if you want your single pickup to keeps its tonal characteristic, where next?
Well that is where the dummy coil approach comes in. In simple terms, a dummy coil can simply be a single coil with its magnet component removed, and of a similar resistance to the normal coil(s) needing noise cancelling. This dummy coil can either be an 'air-core' (i.e. alnico rod poles removed) or with non magnetic rods still in place. The key requirement is that the dummy coil has its windings and / or its physical up / down orientation arranged to be in opposition to the live coil(s).
There are 2 options for connecting the dummy coil (see diagrams below), either in parallel or series with the live coil(s). The parallel connection is similar to the standard Strat positions 2 and 4 (except using a non-magnetic dummy), and the series connection is similar to a humbucker configuration (but again with a non-magnet dummy). The dummy coil is shown in yellow in the diagrams and any tone controls are omitted for clarity. 
The same principles apply for a one, 2 or 3 pickup system. In terms of the connection polarity, its a 50% chance of being right first time!. But what is important to know, is that mounting the dummy coil upside down is the same as changing the polarity of its connection. The difference in background noise will be your guide to which polarity works in your guitar.

 

single coil pickup dummy coil
So what does a single coil pickup dummy coil sound like? Well either connection style will give a similar result. Either way you will notice a reduction in overall output volume. A Strat set to 10 on the volume knob will sound more it has been turned to 8-9 for example. This is not surprising as the dummy coil is effectively subtracting from the live coils signal.
More importantly, a huge proportion of the background hum will have gone. The amount that goes depends to a large extent on how close the dummy and live coil resistances are. A dummy coil of around 80% of the live coils value gives an excellent noise cancellation whilst leaving some 'life' in the signal which is so critical to single coil tone.
The usual complaint / comment about dummy coils is that the resulting tone has a drop in treble. It's a subjective view of course, and the associated drop in volume can add to that impression. But try an A / B switched version of a dummy coil on a Strat, once the volume is equalised out, and you realise that there is really little tonal difference with the dummy engaged, except of course the welcome reduction in background noise.
For me, the series configuration is tonally better than the parallel route, and does not provide the direct route to ground for treble that the parallel configuration has. But I suspect its a very personal decision.
When you realise players like SRV have used dummy coils as part of their set-ups, it must be worth considering.
The RWRP dilemma;
So far so good, assuming what ever pickup(s) you are trying to noise cancel have the same winding polarity / direction. In those cases, the dummy coil only needs to be the opposite winding (or mounted upside down in relation to the live coils). But what if (as in most modern Strat 3 pickup sets), one coil is reverse polarity relative to the others? Clearly to get the same cancelling effect with all of the pickups, you need some clever switching and possibly more than one dummy to get the inverse polarity through all of the pickup normal combinations. There is actually a wiring method for a RWRP Strat pickup set using a standard 5 way switch and one dummy coils that automatically connects the dummy the right way round in all switch positions (and 'out of circuit' for the position 2 and 4 tones). this needs some very creative thinking and a very good understanding of how the 5 way switch works. See my earlier blog;
Stratocaster 5 Way Switch Tricks
So to finish off, there are another couple of very noteworthy ideas along the same theme. They basically still use a dummy coil, but instead of a 'magnet-less' pickup, the noise cancelling coil is incorporated into a guitar (e.g. Strat) backplate or under the scratchplate itself. Some neat user adjustable mini potentiometers allow fine tuning to match your pickups.
Check out the Ilitch systems at;
http://www.fralinpickups.com/bpncs.asp        or
http://www.ilitchelectronics.com/strat-bpncs-3/

 

24Aug/15

Stratocaster 5 Way Switch Tricks

Stratocaster 5 Way Switch Tricks:

The humble Stratocaster 5 way switch is a much overlooked part of a Strat (or Tele or any other guitar!) hardware.
In a normal Strat configuration, the switch happily works away selecting pickups and tone filters. But once you understand how it works, the Stratocaster 5 way switch becomes a wonder of custom mod possibilities. The first thing to realise is that each unit actually contains 2 separate switches, normally electrically connected. There are 2 basic styles, shown in the diagram below, but electrically they are the same.
Stratocaster 5 way switch
The diagram above is from a great feature called '5 way switches explained'. Follow the link below to check it out.
http://alloutput.com/guitar/5-way-switches-explained/
Unleash the Beast! 
From now on I will refer to the in-line style switch numbering in the photos below to avoid confusion.
Stratocaster 5 way switch
Stratocaster 5 way switch
So the first thing to do is electrically separate the 2 switch parts. Which ever style of switch you have, there will be some form of connecting wire between the 2 output 'wiper' terminals of the switches (marked 4 and 5 in these photos), and normally another connection linking them to the volume potentiometer.
The first task then, is to remove that link between the 'wiper' tags, leaving one switch half connected directly to the pickups and the other half to the tone pots (typically just 2 of those in a standardly wired Strat). In the photo the red and yellow twisted pair are the connections to the tone pots. Ensure the link to the volume pot is coming from the '4' tag associated with the pickup half. That is the single red wire in the photo below.

Stratocaster 5 way switch

Thats gives you the 2 sparated switches, so the tone pots must now be connected onto the same half of the 5 way switch as the pickups (and of course to the same relative pickup positions, middle and bridge). The photo below shows this in practise.

Stratocaster 5 way switch
Stratocaster 5 way switch

So now the old tone control half of the 5 way switch is completely freed up for modding use, the other half of the switch handing pickup selection and tone controls simultaneously. 
To understand what can be achieved, you need to consider which of the 5 switch positions uniquely connect what to what. Referring to the standard switch number positions and the numbered switch poles in the photos then;
Switch positions 1 (i,e, selecting the bridge pickup), 3 (middle pick) and 5 (neck pickup), uniquely connects the output tag of the freed up 5 way switch (pole 5) to poles 6, 7 and 8 respectively.
Switch position 2 uniquely uniquely connects the output tag of the freed up 5 way switch (pole 5) to poles 6 & 7 (i.e. poles 5, 6 & 7 are all electrically connected together).
Switch position 4 uniquely uniquely connects the output tag of the freed up 5 way switch (pole 5) to poles 7 & 8 (i.e. poles 5, 7 & 8 are all electrically connected together).
So what can you do with these options?
Humbucker coil tapping. 
If you have a humbucker in your set-up (say the bridge), its easy to use the newly freed switch to 'auto coil-tap' in switch position 2 by connecting a ground to switch pole 6 and the humbuckers coil tap wire(s) to pole 7. As we have seen, switch position 2 uniquely joins these 2 poles together and will engage coil-tapping just in this one position.
Ibanez have a neat trick to do this on an HSH rig from a standard 5 way switch. See the bottom of the the Ironstone HSH support page;
humbucker-hss-hsh-coil-tapping
Switching in additional treble cut circuit.
A fixed resistor and capacitor connected between the main signal and ground form a treble cut circuit. Say you want switch position 4 to have a higher level of treble cut for rhythm work than either the bass of middle pickup / tone control sets normally give.

Simply connect pole 7 to the output of the main part of the switch (pole 4) and the capacitor / resistor string of your choice to pole 8 (the other end of the resistor / capacitor pair would go to ground like any tone control wiring.
Telecaster tips and tricks.
With a Telecaster (or any 2 pickup guitar), a standard 5 way switch effectively gives you 2 extra switch positions to play with beyond simple Bridge, Bridge + Neck and Neck.
So for example, connecting the Bridge pickup to the normal 'Bridge' switch terminal and the Tele Neck pickup to what on a Strat would be the 'Middle' switch terminal gives you the normal Tele 3 way switching and leaves 2 more switch positions to experiment with.
The Ironstone Telecaster 5 way set uses an unmodified Strat 5 way switch to achieve both Parallel & Series pickup configurations as well as a simulated out of phase tone. The later is produced by inserting a small value capacitor in the signal line using the 5 way switch, to block a certain level of bass, giving rise to the distinctive thin tone. Similar levels (and more) of modification are of course possible with a Strat 'super switch', a 4 bank monster. But for most needs, clever use of a standard 5 way switch will achieve the same thing.
Other 2 pickup configurations.
To get the most out of a 2 pickup guitar with a 5 way switch, its worth starting somewhat differently. By that I mean go back to the basics of a 5 way switch actually being 2 separate switches that step through the terminals together. So think about one pickup being dedicated to one half of the 5 way switch and the other pickup wired to the other half. For this sort of set up you will need to keep the 2 'outputs' terminals (4 & 5) connected so that in at least one switch position, both pickups are supplied to the volume control.
In Conclusion:
So there you have some ideas for 'de-constructing' how a standard 5 way switch operates, and the sort of things that can be achieved.
There are plenty of ideas and schematics on the internet if you hunt them down.
A site that Ironstone have recommended before as a great resource is;
phostenixwiringdiagrams


Have Fun!

 

16Aug/15
Ironstone Guitar Pickup Wiring

Ironstone Electric Guitar Pickup Wiring

Ironstone Electric Guitar Pickup Wiring:

The majority of single coil guitar pickups use a pair of standard unshielded wires to make the connection between the pickup winding themselves and the main guitar switching components. Normal electric guitar pickup wiring. But sensitivity to unwanted ambient electrical noise - always an issue with single coil pickups - is increased with the length of any cabling run. So Ironstone thinks it makes sense to replace old style wiring with Audio grade shielded signal wire.

Buts its a bit different to connect up, so Ironstone Pickups have produced a support page describing and illustrating with photos the best electric guitar pickup wiring and connection practice.

 

Guitar Pickup Wiring

 

So check out the page below to see how to do the best job of connecting up your new Ironstone's and benefitting from some extra single coil noise immunity.
Guitar Pickup Wiring

 

 
 
 
06Aug/15
Best Strat Pickup Mashup

Best Strat Pickup Mashup

Best Strat Pickup Mashup:

So picture this best Strat pickup mashup. You have just acquired a nice old Strat as the basis for a super versatile 'best of all electric guitar tones ever' project. You have got all sorts of weird wiring ideas in mind but first off you want to decide what style of pickups (e.g. Tele / Strat / P90 / Active etc etc) to put in (and where).
Luckily this imaginary Strat body has a big 'swimming pool' routing, so there is plenty of room for anything. But you want to limit it to just 3 pickups; Bridge, Middle & Neck for normal Strat 5 way switching.
Where to start?
Bridge Pickup; 
For me there is really only one contender. The peculiarities of the Telecaster Bridge design make its tone both unique and a must-have in this mashup. And with some clever switching (see later) it could even be made into a quasi-Humbucker! It will never sound like a Strat Bridge of course. 
And to really add some interest, how about one of Graph Tech's 'Ghost' saddle mounted piezo pickup systems?
http://www.graphtech.com/products/brands/ghost/ghost-pickups---guitar
Best Strat Pickup MashupWant to see how different Strat and Tele pickups are? 
See; Stratocaster Telecaster Comparison
Best Strat Pickup Mashup
Middle and Neck Position:
OK, just 2 pickups to go, so now it gets difficult. Surely there needs to be at least one genuine Strat single coil in there, and for the genuine tone that has to be passive rather than active? And a real Humbucker (with some coil splitting)? 
Nothing quite sounds like a P90 either (particularly in the Neck position), but is there space for such a niche tone in the best Strat Pickup Mashup?

 

What goes where?:
So on balance, this mashup is going with a Strat single coil and a Humbucker to complete the trio. Because nothing else quite captures the tone of a Strat Neck pickup, the single coil will go in the Neck position, leaving the Humbucker in the middle slot.
So thats the basic line up;
Bridge = Telecaster Bridge pickup
Middle = Humbucker pickup
Neck   = Stratocaster Neck pickup
Best Strat Pickup MashupBest Strat Pickup Mashup

Some Clever Switching?:
That is the basic choice made, but there's more to be squeezed out of this seemingly unrelated combination. 
Some guitarists add a small metal plate under a Strat pickup to make it sound more like a Tele. What would happen if the earth connection was removed from the Tele Bridge pickup's plate? 
And it would be great to somehow magic up a Humbucker in the Bridge and Neck positions. Well one of the reasons for putting the Humbucker in the Middle is so that it can have its coils split (known as tapping - see Humbuckers and Coil Tapping).
That means its split 'single' coils can be combined with the true single coils of the Tele Bridge and Strat Neck pickups. Using the normal Strat 5 way switch will give something close to the Stratocaster 'quack' position 2 and 4 tones.
But its also possible to arrange for switching to add the split humbucker coils in series with the other 2 single coils. Depending on relative magnetic and winding polarities, this would give a quasi humbucker pickup in both the bridge and Neck position, Wow! 
see this web link; 
http://www.premierguitar.com/articles/Adding_Series_Switching_To_Your_Strat
In Conclusion:
So that's my fantasy Best Strat Pickup Mashup!
Each of the 3 pickups I have chosen has a unique tonal characteristic in its own right. With some clever switching its possible to convert that basic 3 into an HSS, or HSH, or even SSS configuration. And all that tonal variation from just 3 humble pickups. Maybe I need to build one to see how it all works in practise!
We may all have our favourite styles and manufacturers / models of pickups, but I hope this Blog may spark some curiosity and experimentation.

And if you want some fun designing (virtually) your own custom guitar online check out the following links;
http://www.usacustomguitars.com/virtual-guitars/virtual-guitars-s/
http://guitarwtf.com/2012/04/27/free-virtual-guitar-builders/

Have fun! 
 Best Strat Pickup Mashup
 
 
27Jul/15
Guitar wiring modifications

Guitar Wiring Modifications

Guitar Wiring Modifications:

Electric guitar wiring modifications allow a standardly configured 'stock' guitar to be turned into something very very different. There are a variety of active modifications and circuitry available (especially popular amongst bass players and in the USA more generally), but this blog concentrates purely on 'passive' guitar wiring modifications.
Apart from a little knowledge, all that is needed are some basic tools and a bit of practice soldering (Youtube is a great source of videos for soldering beginners). This blog does not give you detailed instructions for any single modification, but gives a general introduction and some great links.
So what can be achieved with a 2 or more pickup electric guitar?
Phase switching;
When 2 pickups are selected together (see below for parallel / series), they will be in the phase relationship set by the guitar manufacturer. Using a relatively simple switch, this phasing can be reversed. The result is a thin tone, a little like listening to a guitar through a small radio speaker.
Parallel vs. Series:
When any 2 pickups are selected together in normal Strat / Tele, and other guitar set-ups, they are normally electrically connected in parallel. That simply means both the negative wires of the 2 pickups are connected together, and so are the 2 positive ends. If each pickup is 6kOhm in value, the resulting pair will measure just 3kOhm.
In a series configuration, the pickups are electrically 'added', so the same two 6kOhm pickups would produce a 12kOhm 'effective' pickup. In fact if the phasing is correct, this can become a quasi-humbucker pair.   
See Ironstone's Electric Guitar Pickups Explained
Tone control options:
Some of the easiest mods surround the tone control functionality. This can range from altering which Strat tone controls impact which pickups to treble bleed circuitry to the famous 'Gibson vintage' tone control wiring.
See;
Guitar Potentiometers & Capacitors
Treble Bleed Circuits

Humbucker options:
As you can see from the Guitar Pickups Explained link above, Humbuckers are really 2 entirely separate single coil pickups mounted side by side. Cheaper versions have just a 2 wire output like a normal single coil pickup. But more versatile humbuckers (like ironstone's) allow access to both coils individually, so called 4 wire humbuckers. These allow the 2 coils to be switched and added together in different ways as well as 'turning off' one coil (known as coil tapping).
See;
Humbuckers and Coil tapping
Other combinations;
There is then an array of modifications to combine pickups differently (e.g. the famous 'Gilmour' Stratocaster mod adding the Bridge and Neck pickups), 'kill' switches, and 'solo' switches (bypassing tone and volume controls. Start putting some of the options above together and there are some seriously complicated possibilities.
In fact there is wealth of information out there on the web already, so I am not going to duplicate the brilliant efforts of others. Highlighted below are 4 of the best sites. Each has its own compendious listings of diagrams for every guitar and combination you can imagine! So dive in and see what is out there. If you are serious about custom modding, its worth investing in a cheap and cheerful guitar just to experiment on, before your pride and joy gets some treatment. Enjoy! 
 
related web resources;
20Jul/15
guitar pickup harmonics

Guitar Pickup Harmonics

Guitar Pickup Harmonics:

Starting with the basics, guitar pickup harmonics (for electric guitars), relate to how a guitar string vibrates and how pickups sense those vibrations. Simplistically, the primary frequency that a string vibrates at is called its fundamental. So the treble E string on a normal 6 string electric guitar has a fundamental frequency of approximately 330Hz. But if you play the same string at the 12th fret you will be playing one octave higher. An increase of an octave is a doubling of frequency, so 2x 330Hz (approx 660Hz). 
But let's go back to that open treble E string. Its fundamental frequency may be 330Hz, but the same string is also simultaneously vibrating at other 'harmonic' frequencies, simple multiples of the fundamental.
So the second harmonic is twice the fundamental frequency (approximately 660Hz, the same as fretting the same string at the 12th fret). There is also a third harmonic (approximately 990Hz ) and so on. The 'harmonic tuning' method many guitarists use regularly exploits the higher harmonics up at the fifth frets.
The links at the bottom of the blog give some great visual representations of these harmonics in action. 

What becomes clearly when you see this diagrammatically, is that the physical position of pickups along the strings length is key to its tonal output. A pickup position immediately under a stationary 'node' on a string will result in the pickup not sensing that node and thus not that harmonic at all.
And of course, these fundamental and harmonic frequencies also vary at every string fretting up and down the fretboard. The pickup design, but also the relative positions of the pickups along the string significantly impact the characteristic of a guitars tone.
And the point along a string it is plucked will also affect the mix of harmonics generated and thus 'sensed'. Hence playing a chord at the bridge generates a more cutting tone than the same chord strummed with a plectrum over the fretboard itself which gives a mellower 'dominant fundamental' tone.
For self builders, the topic of pickup positioning is clearly yet another area for explanation. For anyone with a guitar with fixed pickup positioning, this has hopefully at least given a glimpse as to why some guitars and their pickups sound as they do (and how plucking them differently can drive new tone).
And checkout Ironstone's own page on basic pickup design;
Electric Guitar Pickups Explained via the Full Details link
guitar pickup harmonics
 
 
Related web resources;
07Jul/15
Best Stratocaster pickups

Best Stratocaster pickups

The Best Stratocaster pickups?

'Which are the best Stratocaster pickups?' A very common question on guitar forums, but at its heart very difficult to answer. And that is largely because we all experience guitar tone differently and have our own favorite tones that we seek. So I am not going to try to answer the question directly!. 
But what needs to be clearly understood is that Stratocaster pickup construction (as all pickups) is a series of design choices aimed at delivering a particular tone well, and other tones with varying levels of compromise.

Some of these design choices are well known and documented. More windings = higher resistance and a 'hotter' tone. Alnico magnets are tonally warmer than ceramic, etc etc. But here are 3 often overlooked design factors, that are also vital to a pickups tone. 

The winding cross-section;

Stratocaster pickups are conventionally wound on some form of bobbin. But a fixed number of windings can give a different tone depending on the cross -section of those windings. A taller thinner bobbin, will give rise to a taller thinner cross section of copper winding. That generates a slightly lower overall output, but with a higher treble content. A shorter wider bobbin (and winding) will give a higher relative output and  a 'fatter' midrange.

Bobbin Style;

Traditionally, bobbins were a 2 part construction. A pair of fibre plates (flat work) were arranged at the top and bottom of 6 magnet pole piece rods. This is in contrast to a modern production route of a moulded one piece plastic bobbin. In this the pole pieces sit in 'wells' surrounded by the moulding. So consider the effect on winding cross-section as described above. By their nature, the moulding surface on which the windings will lay in a plastic bobbin will be slightly longer and wider than the traditional construction. So the same resistance of winding (i.e. its total length) will have slightly less overall windings and they give a relatively thinner cross-section. These factors all tend towards, brighter and cleaner tones for a given resistance. Clearly, as the traditional build, many guitarists favor fibre bobbin pickups. But moulded bobbins pose an interesting alternative as well as allowing infinitely more adjustment of the pole pieces.

Pole piece Stagger;

Stratocaster pickups in particular are 'defined' by the style and variance of their pole piece stagger. This ranges from the full 'Vintage' stagger where all 6 poles are of differing heights, to perfectly flat pole pieces. The important thing is their relative height differences to each other. How far the shortest one protrudes above the pickup cover is not so important. This is quite a complex topic and significantly affects the he overall sound of a pickup when playing chords for example, as it determines the relative volume of any string in the mix. See Ironstone's support page on the topic via the Full Details link below.

full-details2

All of the above are elements of pickup design we consider here at Ironstone. But ultimately its up to your ears to find your best Stratocaster pickups. For those who like see and hear comparisons, check out the amazing Guitar Tone Database link (agdi.com) below.
02Jun/15
Best Strat Pickup Mashup

Stratocaster vs Telecaster Pickups

Stratocaster vs Telecaster - a pickup comparison:

Welcome to the first post on the new Ironstone Blog. 
Maybe its an obvious starting point, but one of the commonest questions Ironstone get (and all over guitar Forums too!), concerns the differences in tone of Stratocaster vs Telecaster.  Now just to be clear, there are many subtle variants at work, but logically the Ironstone focus is on the key differences between the pickups themselves.
A bit of digging soon reveals that it is the differences in construction that drives the very different tonal qualities. And there are some other ways to illustrate the effect these design differences have other than just listening to tone.
And that sparked off the thinking behind the Ironstone support page detailing Stratocaster vs Telecaster pickup comparisons. So click the Full Details link below and discover the hidden world of guitar pickup magnetic fields!
 
full-details2
 
 Stratocaster vs Telecaster Pickup Comparison 1
Related web resources;