Pickup Winder: Strat Pickups Part 2

After a successful trip to Jaycar in search of rare-earth magnets, I'm ready for the second step in the winding of a set of single coil Stratocaster pickups - magnetising the pole pieces. To do this, two magnets are needed with opposing poles. The magnets are mounted with opposing poles facing each other and the pickup is passed between them.

Using my son's orienteering compass, I determined the polarity of each magnet and stuck them to the jaws of my nut-making vise with just enough room for the pickup bobbin to slide comfortably between them (nothing like wrestling some strong rare-earth magnets!).

Testing the polarity of my rare-earth magnets

Using my nut vice to hold both the opposing magnets

Once the magnets were in place, I took each bobbin in turn and passed them through the gap. It was pretty damn hard keeping the pole pieces from sticking to the magnets! I did 40 passes with each bobbin to (hopefully) fully magnetise each Alnico V pole piece.

Magnetising the neck and bridge pickups as north-facing.

To allow for noise cancelling when the middle pickup is used in parallel with either the neck or bridge pickup, the middle pickup needs to be RWRP - or "reverse wind, reverse polarity". Half of this equation means that the polarity of the pole pieces for the middle pickup need to be the opposite of the others. Therefore, having passed the bridge and neck pickups through the magnets in a "north facing" configuration, for the middle pickup I reversed the direction to create a "south facing" polarity.
 

Magnetising the middle pickup as south-facing.

After more struggling against the pull of the magnets, a quick polarity test of all three pickups showed that I had succeeded in creating a "reverse polarity" middle pickup.

The resulting polarity of all three pickups compared.

With the pole pieces magnetised, it's now time to crank up the winder and see if I can get some 42 AWG wire on these bad boys. Let's hope I don't break the wire first time out! I will be going quite slowly so fingers crossed for no mishaps. I will also be stopping every 500 winds or so to measure the resulting resistance of the coil. That should complicate the process quite nicely ;). Anyway, I need some nail polish before I continue on, so stay tuned for the next installment!

Pickup Winder: Strat Pickups Part 1

I finally got some time today to start wiring a set of 3 single coil pickups for my Ash Stratocaster build. The first step in getting the pickups wound is to assemble the pole pieces into the flatwork, and that's what I ended up tackling. The pickup kit that I purchased from aliexpress.com came complete with the flatwork (with eyelets already inserted), alnico V polepieces (unmagnetised) and push back vintage wire to create all 3 pickups.

Strat pickup kit and the tools to assemble the flatwork.

The pole pieces were already bevelled on one edge, removing one step in the process (phew). The pole pieces that came with the kit were the following sizes: 3x18.7mm, 1x18.3mm, 1x17.5mm and 1x19.8mm. Referring to the pickup winding guide from Stewmac as a rough tutorial, I assigned these pole sizes to the string positions as follows:

E: 18.3, A: 18.7, D:18.7, G: 19.8, B: 17.5, E:18.7

Using my regular hammer, I bashed the non-bevelled ends of the pole pieces into the bottom flatwork, making sure that the eyelets were facing up. In preparation for lacquering the completed bobbins, I also covered the eyelets with a little painters tape. It took more effort than I was expecting to get these pole pieces seated - the holes in the flatwork are quite a deal smaller than the diameter of the pole pieces themselves, and this combined with my sausage fingers meant that it took quite a bit of effort to get them hammered in.

Pole pieces finally bashed into the bottom flatwork.

With the pole pieces now in and standing, it was time to get the top flatwork installed. To make sure that it was installed at the correct height, I created two 11.5mm high guides out of plywood to sit either side of the pole pieces.

11.5mm high guides cut from plywood and held with a rubber band.

Held in place with a rubber band, these allowed the top flatwork to be hammered home without mishap. To help me, I created a small tool from a piece of perspex whose 55mm diameter hole fit over each pole piece and allowed me to lower the flatwork around it. This was another useful hint from the stewmac winding guide, and it really saved my arse.

A piece of perspex with a 55mm hole. A genius hint from Stewmac.

Although it took a little bit of fiddling to get all the pole pieces lined up with the holes in the top flatwork (especially the lowest B string pole piece) I soon had all the pole pieces hammered through and looking great!

Pole pieces installed! This baby is almost ready for winding.

After the first bobbin was assembled, I went on to complete the remaining two. Yet again it took more time than I was expecting (most time was taken with the initial hammering pole pieces into the bottom flatwork) but finally I had all three bobbins assembled and ready for the last step in their assembly.

Three strat bobbins all assembled and ready for lacquer!

This last step is to spray the entire bobbin with lacquer to make sure there's no electrical conductivity. This was achieved using the dregs of my White Knight acrylic cans from a previous build. I used a piece of hookup wire through the screw hole to hold each pickup for spraying and later hanging to dry. The painters tape hopefully stopped any lacquer from coating the eyelets!

Bobbins sprayed with Lacquer and hanging to dry.

So there you have it! 3 assembled strat pickup bobbins ready for step 2 in the process - magnetising the poles. I need to source some rare earth magnets from Jaycar during the week so that I can get this done and be ready for winding. Exciting times!

Les Paul Jnr Double Cut: It's Finished!

Well, the Les Paul Jnr Double Cut was finally finished today - Woohoo!! I am very happy with how this one came out. In terms of the wiring mods discussed previously in this blog, in the end I used only a single push-pull pot to bypass the tone circuit. The tone bypass is the default - you have to pull the tone pot up (out) to enable the tone. In the down position you get the full dynamic range of the P90 without any modifications.

Apart from the custom scratchplate & truss-rod cover, only a small number of further changes were made above and beyond the stock Pitbull kit. I added an Orange-drop tone cap to the aforementioned push-pull tone pot for the tone circuit, and added a switchcraft output jack with an oval base plate. Lastly, a pair of black speed knobs finished off the look.

I couldn't be happier with how she has turned out. Even though the tuners, bridge and P90 are all stock standard from the Pitbull kit, she plays very nicely indeed with plenty of grunt and oodles of sustain. I would still like to get a P90 from GFS for this bad boy when funds become available, but what's there now sounds amazingly good anyway (go figure!). With a bone nut and the action dialed in, she's low to the deck and silky smooth! Man, I can't put this baby down - especially with the distortion cranked way up! Heaven..

Les Paul Jnr Double Cut: Wiring for a Single Pickup

Looking at the wiring for the Les Paul Jnr, I came across this interesting schematic from the Guitar Wiring Blog which provides for multiple tone options from a single, single-coil source. The circuit uses two on-on switches to provide both a tone bypass function and the choice of 2 different capacitance values when the tone circuit is engaged.

Here's how it works. Firstly we start with a standard single-pickup circuit with a volume pot and tone circuit:

We then add two cutoff switches (both controlled from the same physical switch) to provide the ability to completely remove the tone circuit when required:

To this we then add a second switch that selects between 2 separate capacitor values when the tone circuit is active:

And there you have it. Cool huh? A big thanks to the Guitar Wiring Blog for this idea.

For me this is an especially great idea for the Jnr as it only has the single P90. I have two push-pull 500K pots waiting on my workbench for just such an application, and so this seems too good an opportunity to pass up! I really think this baby is going to sound great with the tone bypass engaged. Makes me wish I could afford a new P90 pickup for this baby as well (I've had my eye on the GFS Dogear P90 for a while now) but the boss has frozen all guitar upgrade funds for the time being. This said, I'm planning on wiring in a wire terminator so that I can swap out the pickup very easily in the future :).