Wax Potting and Microphonics

Splitting humbucker coils

Humbuckers are essentially two single coils, side-by-side, wired in series (out of phase to "buck" the hum).  One cool feature is that you can split the coils and use them as true single coils to get a brighter, cleaner sound.  I say "split" the coils instead of "tap" the coils because that is something different entirely that gets confused often.  Coil "tapping" is having multiple leads going to the same coil to access different output values.  In order to "split" your coils, you must have four leads (five, including the bare ground wire).  Here are some common humbucker color codes:

By connecting the South finish (-) and North finish (+) you have both coils wired in series with South start (-) connected to ground and North start (+) connected to the volume lug or the switch.  The wiring diagram below shows how to wire my Apex Humbuckers to a switch like a push/pull potentiometer to switch between "single coil mode" and "humbucker mode".  You will notice that my color codes are the same as Lawrence and Gibson.

If you look at the Tele wiring diagram above you will see that when the tone control is pulled up the lower lugs are engaged and the finishes for the bridge pickup become the "hot" lead.  Ground stays at ground, that means the bridge South coil is engaged.  Simultaneously, the right side lugs connect the finishes for the neck pickup to ground, making them the negative lead.  Hot stays hot and you have the neck North coil engaged.  When the neck North and the Bridge south are used together (the middle switch position) they are hum-canceling because they are reverse polarity, wired in parallel, out of phase.  

On most humbuckers, the coil with the adjustable poles is South-up, you can check by using a compass.  The North needle will be attracted to the South-up pole and South will be attracted to North.  My Apex Humbuckers do not have adjustable poles, but North-up and South-up coils are labeled on the bottom or you can use a compass to check.  

You can have a lot of fun getting some different sounds out of your instrument just by wiring it differently.  One of my favorite websites for wiring diagrams is www.guitarelectronics.com.

Pickup Magnetism

magnetizing a strat pickup with powerful rare-earth magnets

With all the talk out there about scatterwinding and coil wire types, it's easy to forget about how much of a role the magnets play on the sound of the pickup.  A lot of pickup manufacturers will charge the poles all the way up and be done with it giving little thought to "tuning" the magnets, but a few of the boutique builders out there will take the time to "hand weaken" the magnets.  

To charge up the poles, rare-earth mangets, like those used in guitar repair, are placed in the jaws of a vice.  One has it's north pole facing in and the other south.  The rare-earth magnets will charge the Alnico poles with the opposite charge, north charges south and south charges north.  This is because we all know that if you put two magnets with a south polarity in close proximity, they will repel or demagnetize each-other.  As the bobbin with the magnets is swiped between the rare-earth magnets, it is fully charged to about 35 gauss.

A fully-charged south-up Strat pickup

Now that the pole is charged all the way up, we can widen the jaws of the vice to about twice as far as they were before.  The pickup is flipped around so that it's south pole will be facing the south pole of the rare-earth magnets and north will be facing north.  With the jaws of the vice farther apart, we are just weakening the magnets a little bit, the closer we move the jaws of the vice, the more magnetism we are removing.  It only takes two or three swipes through through the jaws to weaken the poles a little bit.  In general, I weaken my neck pickups to less than 30 gauss and my bridge pickups to less than 20 gauss.

By weakening the magnets, we are essentially aging the pickups to sound like something 40 or 50 years old.

Setting pickup height

Depress the first and sixth strings at the last fret.  Now with a ruler measure from the bottom of the string to the top of the pole.  In general, bridge single coils should be about 1/8" away from the strings.  Humbuckers can be set a little closer.  The closer the pickup is to the string, the more bright or harsh the tone will be, the farther away it is the warmer the tone.  Once you get something you are happy with you can move on to the neck pickup.  Since the strings are vibrating farther over the neck pickup, this pickup will always be louder and warmer than the bridge pickup.  Lower the neck pickup towards the body until the volume is even with the bridge pickup.

It's really a matter of personal taste and there is no wrong way to set magnetism or pickup height, but if the pickup is too close to the string it will pull on it too hard, killing your sustain and messing with intonation.  If the pickup is too far away it will sound too dark and quiet.  

How do humbuckers work?

Humbuckers are great for their warm, powerful tone, and best of all they "buck" the hum that single coils are usually are prone to.  60-cycle hum comes from electronics that surround us every day like florescent lights and power transformers, and it sure doesn't sound very good when it comes through an electric guitar amp.  That's why humbuckers were such a valuable invention when music was getting louder in the 1950's, but how do they work?

Humbuckers are basically two single coils arranged side-by-side (fig. 1), each with six magnetic poles or slugs (one for each string).  They are wired in a way that cancels the unwanted frequency and keeps as many of the good frequencies as possible.

fig. 1

Most modern Stratocaster guitars (fig. 2) have a humbucking option built in.  The middle pickup is reverse-wound/reverse-polarity to the neck and bridge, so that when they are used in combination they will cancel any hum.  This only works because the two coils are so far apart and the harmonic frequencies are so different, the only quality that is the same about them is the hum, so when the two coils are opposite, they cancel the hum. 

fig. 2 the middle and bridge or middle and neck pickups are hum-canceling together

 Humbuckers function a little differently than this. Since the coils are so close together (as close as they can possibly be without being on top of each other), they are sensing very similar sounds and they need to be out of phase to cancel the hum.  Humbuckers consist of two coils (both wound counter-clockwise) with opposite magnetic poles facing up, usually wired in series.  

Some people don't like how humbuckers aren't as clear or bright as single coils, but what a lot of people don't realize is that there are many different ways of building humbuckers to change the tone.  The original Seth Lover PAF humbucker (which is the baseline against which all other humbuckers are judged) consists of 5000 uniform winds per coil (not scatterwound), bar magnets mounted underneath, adjustable poles on one side, slugs on the other, topped off with a nickel-silver cover.  All of this makes for a pretty dark sounding pickup.  Which might sound great in certain guitars, but some guitars beg for bright, twangy tones.  You could use scatterwound coils (for a brighter, clearer sound) and solid Alnico polepieces much like a Strat pickup.  This is the formula I used for my Apex Humbuckers.

fig. 3 my Apex Humbucker

You could also have an underwound humbucker (say with 4000 winds per coil) for a brighter tone, and you could wire these coils in parallel (instead of in series) for pickup with a clear tone and absolutely no hum.  

So there are lots of different options when it comes to getting different tones out of humbuckers, they don't always have to be dark sounding.  Most modern humbuckers come with 4 conductor leads so you can split the coils, and you can look up a wiring diagram here to experiment a bit.  Knowing your color codes of your pickup wires will be very helpful too, here is a link to color codes of a number of popular humbucker manufacturers.

Strat Mod

Increase your tonal possibilities while leaving your Strat looking bone stock

a normal 250k tone control on the left and the modified push/pull pot on the right

One thing I have always loved about the Telecaster is the middle position of the pickup selector where you have the bright, aggressive tone of the bridge pickup combined with the warm, bassy sound of the neck pickup.  This is a sound that you don't normally hear coming from a Strat, but with a fairly cheap and simple mod you can achieve this and other tones, enhancing your tonal possibilities and without sacrificing any of the other tones or the looks of the guitar.

I can perform this mod to any Strat for about $50.  I can also make custom, pre-made pickguards with pickups, a switch, and volume and tone controls all wired up and ready to drop in your strat.  All you have to do is solder the output jack and connect it to the body with the included screws.  The cost of this depends on the options you include (pots, capacitors, pickups...) the sky is the limit.

Email me at schuylerdeanguitars@gmail.com to inquire about modifying your Strat.

If you are feeling particularly ambitious you can try this mod yourself.  Here is a link to a wiring diagram:

http://www.guitarelectronics.com/product/WDUSSS5L2101/WDU-SSS5L21-01.html

Just keep in mind that you will need a good soldering iron with a small tip, a 250k push/pull pot with a short rotary knob and a second capacitor.

Eliminating electrical noise in your guitar

For many of us who love the sound of single coil pickups (eg. classic Strat or Tele) we are familiar with 60 Hz hum, radio stations, and cell phone signals coming through our amp.  This is electrical interference that our single coils are especially susceptible to, and yet we refuse to give up single coils, we just love the tone too much!  Humbuckers are a great way to fight this 60 Hz hum, if you have ever played a guitar with a humbucker and a true single coil you can easily hear the difference, but a lot of players complain that too much tone is lost when the hum is "bucked."  The truth is, you can stick with your old single coils as long as you follow a few DIY procedures that are guaranteed to reduce the noise to an absolute minimum.  Even if you have humbucking pickups these steps will help reduce the overall noise of your rig.

Step 1.  Shielding Paint

With the pickguard and electronics removed from the guitar, you can paint shielding paint from Stew-Mac on the inside of the control cavity and the pickup routs.  Two or three coats (allowing it to dry overnight between coats) should provide enough coverage.  All grounding material must come in contact somehow with the back of the potentiometer (ground).  Connect a ground wire from the paint to the back of a potentiometer or paint up to a screw hole so the paint comes in contact with the copper tape on the back of the pickguard (see step 2).

Step 2.  Copper Tape

This tape (also from Stew-Mac) is great for sticking to the back of pickguards and totally blocking out any interference.  The tape is grounded by coming in contact with the switch and potentiometer casings.

Step. 3  Leads

Keeping all electrical connections to an absolute minimum length will reduce the chances of interference.

Also, twisting the positive and negative leads from your pickups (as seen on this Jazz Bass pickup) will help cancel interference.  It is debatable whether this makes a noticeable difference in passive equipment, but it won't hurt, some like it for aesthetics and wire manageability.

Step 4.  Final details

Having a good quality, shielded instrument cable free of cracks and keeping it as short as possible will help tremendously in avoiding interference.

further reading:

Eliminating Troublesome Hum & Buzz Created By Electric Guitars by Bruce Bartlett 

Canceling Tele hum on the cheap

For more than 50 years, the Fender Telecaster has been manufactured pretty much the same way. It's trademark sound is one of raw, gutsy tone with sharp attack and great clarity. Because of it's simplicity and honesty, it is perhaps the best way to showcase a pair of single coil pickups. One of the drawbacks of true single coils is their hum which guitar makers have been trying to fix for decades. Since the Telecaster's design was perfected rather early on in electric guitar history (1950) it is one of the only dual pickup guitars that did not have hum-canceling capabilities, and it still doesn't today. Most of the time the two pickups are made reverse-wound/reverse-polarity so that when they are used in combination (the middle position of your pickup selector) they will cancel the hum. The telecaster design has been pretty much left alone because so many players love the trademark sound and especially the sound you get when the neck and bridge pickup are played together. For a lot of players that is more important than "bucking" the hum, but for you it might be more important to have a quiet setting on the guitar. Here I will show you how to cheaply and easily buck the hum on a standard Telecaster. 

As we just discussed, most Tele pickups are wound the same direction and charged with the same polarity facing up, making them non-humbucking, so all you need to do is switch the leads and reverse the polarity on one pickup. You can test the polarity by holding a compass up to the top of the pickup as shown below. Opposites attract, so this pickup is charged SOUTH UP (fig. 1).

fig. 1

Reversing the leads on a pickup is a simple operation with a soldering iron, but charging the magnets will be a little more tricky.  Especially since most vintage, and vintage-reissue Telecasters have a copper-plated steel baseplate on the bridge and a chrome cover on the neck pickup, which is soldered to the ground of the guitar.  

Modern American Standard bridge pickups, like the one shown below, do not have a baseplate, and are changed NORTH UP (fig. 2), so here I will remove the pickup and charge it SOUTH UP.

fig. 2

This can be done with a pair of 1" rare earth magnets from Steward-Macdonald ($8.57 each).  These are extremely strong magnets that will successfully charge Alnico polepieces like in my pickups here.  They will also successfully erase hard drives like in you iPhone or MacBook, so keep them away from all computerized equipment.  You can see the magnetic field you are dealing with by holding it to a compass .  It is attracting the NORTH needle, so this is the SOUTH pole of the magnet (fig. 3).

fig. 3

Charge the pickup polepieces by moving them back and fourth between the rare earth magnets.  The magnets will change magnetic fields of weaker magnets to what they are most attracted to, so a SOUTH pole with charge pickup polepieces to be NORTH.  Rare earth magnets will hold themselves to the jaws of a vice.  Label the side that will charge magnets to be North as I have done below (fig. 4).

fig. 4

Adjust the jaws so that the magnets are as close as possible to the polepieces but still allow the pickup to pass freely.  Move the pickup through the jaws of the vice a few times and it is fully charged.  Reinstall the pickup with the leads reversed.  Positive leads are usually white or yellow and in this case would be soldered to the ground (the back of the potentiometer), negative leads are usually black, blue or green and in this case would be soldered to your switch.  

If this pickup had a metal baseplate (fig.5) or a cover it would be a little more difficult to charge the magnets but sill possible.  It would require disconnecting the negative (ground) lead from the baseplate or cover and running a separate ground wire from the baseplate to the back of the potentiometer.  Then, special care must be taken to break the hold of the potting wax and remove the baseplate or cover without damaging the coil.  Then you can charge the magnets.  

fig. 5

Now you have a hum-canceling mode on your Tele without effecting the tone of the bridge or the neck pickup!