Hot Wiring your Guitar
One of our recent readers letters, from deepest Wales, asks for general advice on rewiring a Wilson Rapier 33 (does he mean the revered and historic Watkins, I wonder?) from three pick-up to two, the object being a general and experimental hot-up. The letter highlights a whole area that deserves discussion here rather than on a few bits of Basildon Bond and I'd be interested to hear from anyone else with ideas on an overall approach to this type of project.
So meanwhile, dear Mr. Wilson or Watkins owner, and fellow enthusiasts...
I don't know the Wilson Rapier 33 particularly, but I would guess that it would benefit from some physical sorting out before you start on the electrics. As you have other guitars around to cover your gigs, you may as well take your time and go the whole hog on this one. As far as brass hardware is concerned, expert (and "expert") opinion is fairly evenly divided for and against. What I would say is that some guitars have physical characteristics that give good enough results without the help of brass, but most don't, and there's not a lot of point in going to town on your wiring if the guitar is physically stodgy. So I would go for a brass nut right away, fatter frets, and as much brass mass as is practicable at the bridge. All these things have, in my certain experience, the ability to at least lift top end and even-out (rather than necessarily increase) sustain. While on the bridge, check out your string earth. You must have a good contact with the bridge (or the tail-piece, usually done through the guitar body to one of the pillars, and therefore usually not a problem) and if you have gone for plenty of mass, you'll probably end up effectively trying to solder a wire to a very efficient heatsink. A better way of attaching the string earth firmly to the bridge is to drill and tap a small hole somewhere discreet for a more reliable screw contact. I would suggest M3 size, which requires a 2.50 mm drilled hole. An M3 taper and plug tap pair will set you back somewhere between one and two pounds for HSS, but if you only intend to use it once or twice on brass, then the cheaper carbon steel types will do. Make sure you oil the taps when cutting.
I assume you're going to go for humbuckers - personally I see no point in limiting the guitar to two single coil pick-ups. However, I would recommend that you retain the centre pick-up as you already have the space; it is a very valuable mixer. I don't think you need a humbucker here. I have a centre humbucker and find I rarely use it untapped, and a single coil will save space and money. The Dimarzio SDSI is powerful enough here to mix reasonably comfortably with humbuckers. Alternatively, the Lawrence Strat type pickup is in fact a centre weighted humbucker, with the appearance of a single coil. It also collects harmonics from a small area like a single coil and thus has some similar tonal characteristics. Top end is not a major consideration in the centre slot, as top will dominate a pick-up mix more effectively than sheer volume and generally speaking, you don't really want this position to do any dominating, rather it is a good place to collect a few extra harmonics to influence the sound of another pick-up.
I think you should be able to mix a centre pick-up with either front or back pick-up separately, and have found that the simplest control set-up to use is to rig the guitar as a normal two pick-up system but with a route-able centre, so the centre should be wired to an on/off/on SPDT as shown in Figure 1. I don't believe that a separate volume or tone control for centre serves any useful purpose whatsoever (musically).
I have already covered a number of partial and complete humbucker taps in earlier issues of E&MM, I think you'll also find some useful ideas in a little book I have written, Customising Your Electric Guitar, which will be published around August/September by Kaye and Ward, and distributed by Stentor Music - your local music shop should be able to get hold of it for you.
If you really don't want to use a centre pick-up, then the siting of your rear (bridge) pick-up requires thought. Siting close in to the bridge will give you more high harmonics, and a sharper edge to the sound. Siting further forward can, with the right tap, take you closer towards a Strat centre and rear mix (the classic "out of phase Strat sound") but will gradually lose the high, sharp harmonics. Using a phase reverse switch on this pick-up in conjunction with an earth-type tap can help cover the area a little better as you will then have a choice of coils but experimenting to find the best spot will entail extra routing of body cavities and recutting of scratch plates. Which is precisely why I recommend going for a centre pick-up and a close set rear pick-up in the first place!
In fact the more I think about what to suggest, the more a centre pickup seems essential if you want a wide range of sounds. For example, coil phase reverse on a front pick-up can add some useful nasal qualities to a sound, but sounds weedy on a solo pick-up, and doesn't mix terribly well with just a rear pick-up. However, mix a centre pick-up in with it, and if you've got the overall phase of the front pick-up the right way round, you're half-way to a Dobro sound. Or maybe add a parallel coils option to the front humbucker's reversed coil phase, and you can slip a breathy little razor edge into a three pick-up mix whilst retaining the body of the sound and the essential quality of the rear pick-up. If you start juggling the mix a little, or biasing it, that is, a .001 bypass on one pick-up and not the other two, or vice versa, life can start to get very exciting tonally.
Compared with the possibilities available from a three pick-up rig, a two pick-up guitar is positively mundane - and remember, this is all still without batteries. On choice of pickups, the loading and cancellation effects of some of the more complex parallel mixes and phase reverses can cause volume drops, so go for powerful pick-ups. High-power pickups also allow you to exploit a treble bypass capacitor more effectively.
Also, when using in-phase coils on a front pick-up (normal humbucker is out, remember) volume drop as you bend away from a pole-piece will be more than usually severe, so use bar pick-ups if you're a bender. Note that when choosing a production custom humbucker, variation in the number of conductors fitted may restrict your options. High power humbuckers, for example the Dimarzio X2N comes four conductor and shield as standard, so all the options are open; the Schecter Superock comes three conductor and shield for overall phase-reverse and tap, but is very easily rewired to either: three conductor and shield, suitable for series/parallel/tap without overall phase reverse, or fully to four conductor and shield. The Lawrence L500 comes three conductor and shield for overall phase reverse and tap, and cannot have its conductors re-attached or added to as the whole unit is sealed in epoxy. Other makes also vary, so check out carefully as you buy.
Feature by Adrian Legg
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