776. What is scatter winding?
Scatter winding is also called hand winding where the magnet wire is guided back and forth onto the coil by hand. This process is still used today especially for rewinding vintage guitar and bass pickups. Scatter winding is usually done on single coil pickups and is normally not done on plastic humbucking bobbins. Humbucking bobbins need a precise number of turns per layer and proper pitch so the bobbins don’t flair at the ends when being wound.
777. What is the average number of turns for popular model pickups?
This would be a project for you as there are many variations in the number of turns on the many model of Duncan, Gibson, Fender, DiMarzio and other pickup manufactures. Find some old broken pickups and count as you remove the magnet wire turn by turn. It would take you some time but it will give you an idea of how many turns are put onto a pickup. You can also determine a pattern of the way the magnet wire is wound on the bobbin or coil. If you see a consistent pattern then the pickup used an automatic traverse guided control. If the pattern is haphazard then the pickup was probably scatter or hand wound. I made an automatic de-reeler that counts the turns on broken bobbins that I’m repairing and I also use it to remove the magnet wire from a coil so when I repair the broken coil, I can replace the coil with the magnet wire that I removed. This keeps the pickup vintage and the original specifications of the magnet wire. Especially the color, diameter and DC resistance that are important to keeping the pickup close to original specs.
778. What is the number of turns?
The number of turns is usually the total number of turns wound onto a particular bobbin or coil. To increase the number of turns in a particular bobbin you could use a smaller gauge of magnet wire, thinner insulation or increase the winding area of a bobbin or coil. Increasing the tension can allow you to increase the number of turns but will all cause the magnet wire to stretch and increase the DC resistance.
779. What is the ohms per 1,000 feet?
This is found on magnet wire slide rules or gauges supplied from most manufactures and suppliers of magnet wire. It is a gauge to measure the nominal or average ohms of a particular gauge of magnet wire at 20 degrees C. For example the nominal ohms per 1000 feet at 20 degrees C. are:
42 gauge is 1659 ohms per 1000 feet.
43 gauge is 2143 ohms per 1000 feet.
44 gauge is 2593 ohms per 1000 feet.
As you see the higher the gauge of magnet wire the magnet wire is actually thinner which causes the DC resistance to become higher.
780. What is the average ohms per turn in a pickup?
I take a humbucking bobbin that uses 42 plain enamel magnet wire and it reads 3,700 ohms or 3.7k, divide it by 5,000 turns and you get .74 (average) ohms per turn. Remember that the length and width of a pickup will change as the dimension of the bobbin or coil change. Wide and thin coils like Fender Jazzmaster pickups will have a higher average ohm per turn than a narrow and tall coil like a Fender Stratocaster. If you take the ohms of a pickup and divide it by the number of turns if it is known, than you can measure the ohms per turn. The outer turn of a coil will have a higher DC resistance than the inner turn of a coil using the same magnet wire. The outer coil has a longer length of magnet wire even though the measurement may be small, it still will have a different measurement.
781. What is the pitch?
The winding pitch is the same as the pitch or threads per inch on a screw. The pitch is the desired space between each turn of magnet wire on a coil. If the pitch is to wide, there will be a larger space between each turn. If the pitch is to narrow, then each turn may overlap and cause irregular winding or coil shape. On average it’s best to leave about the equal distance between the turns as the diameter of the magnet wire being used. The nominal diameter of a 42 gauge of magnet wire is .0026 inch and the pitch or gap between each turn should be wide enough to place another turn of the same gauge magnet wire. I often wind two magnet wire gauges at the same time for interesting and fun wiring combinations.
782. What is the tension that should be used with magnet wire?
The maximum tension before the wire will stretch causing undesirable or high coil resistance.
42 Gauge is 45 grams
43 Gauge is 35 grams
44 Gauge is 29 grams
783. What is the traverse?
This is a measurement from left to right side of the winding area in a bobbin. If your humbucking bobbin has a traverse that measures .250 inches and you use .0026 inch diameter magnet wire, the maximum number of turns without the wire stacking would be on average 96 turns per layer. Divide .250 inch (traverse) by .0026 inch (magnet wire diameter) and you get 96 turns per layer.
784. What are some of the winding terms?
AWG: AWG is for the American Wire Gauge that is a standardized measurement of wire gauges and is used for magnet wire. When you hear about the various gauges of magnet wire such as 42 gauge, 43 gauge, 44 gauge and so on, it is referring to the American Wire Gauge. The higher the number the smaller the diameter of the magnet wire. I’ve seen charts with ultra fine magnet wires as small as grade 60 AWG. Most charts I have seen only go to 52 AWG with the nominal magnet wire diameter being .00095” (inch).
Wire measurement: This is a measurement that I use to determine the outside diameter (OD) of magnet wire to make sure it fits within my tolerances for winding. If I’m winding many coils and run out of a particular magnet wire, I need to find another spool with the same bare copper diameter, insulation color and thickness and overall the same specifications. I also check for the DC resistance at a 100 feet and 1,000 feet. This will give me a better control of the winding that I’m doing.
Insulation: Insulation comes in many colors and thermal ratings. The colors range from natural, formvar, enamel, green, red, blue etc. The thermal rating determines the melting temperature of the insulation with the common being 105 degrees and others being 130, 155, 180, 200 and 200 degrees Centigrade.
Insulation diameter: The insulation diameter is the diameter or coating of insulation placed over the bare copper wire. Without the insulation the coil or turns would short out. The insulation or build as the magnet wire industry calls is can be minimal, nominal, maximum with single build and heavy, double or triple build available when higher currents flow through the wire.
Tension: Is the measurement usually in grams that measure the maximum amount of tension that a wire can be drawn or pulled off a spool without stretching and causing higher coil readings.
Winding speed: Winding speed that is to fast will pull wire to fast and cause the wire to stretch and increase the resistance in the coils. Coils that are wound to slow can be loose and spongy. Spongy coils can happen to if you wind to fast because the copper wire doesn’t have enough time to firmly compact and take shape before the next turn. If you wind to fast, the coils can flair the inside walls of the flatwork causing irregular coil shapes.
Turns: The number of turns you put on a bobbin is determined by several factors. There is a space factor, frequency, output, pickup position, wire gauge, insulation thickness and basically the kind of tone you’re trying to get. The turns will determine the DC resistance and the length of magnet wire will help determine the resonant frequency.
Tap: When you tap a pickup, you wind to a determined number of turns, run a wire out at that point and continue winding more turns to a determined number of turns. You can wind a pickup with 4,000 turns and tap at that point by running an extra exit wire or eyelet and continuing winding in the same direction with an added 3,000 or needed number of turns. When you tap a pickup, you have added switching and tonal possibilities.
TL/TR: When the top of the bobbin is facing left it is called Top Left or TL. When the top of the bobbin is facing right it is called Top Right or TR.
TC/TG: When the top edge of the bobbin is spinning towards you it is called Top Coming or TC. When the top edge of the bobbin is spinning away from you it is called Top Going or TG for short.
Winding Direction: The coil is wound either Top Coming or Top Going.
Temperature: Used when measuring the DC resistance of a coil at a given temperature. The temperature will influence the DC resistance of a coil. The warmer the temperature the higher the DC resistance. The lower the temperature the lower the DC resistance.
Bare copper: Magnet or copper wire is un-insulated wire without thermal insulation to protect the turns from shorting out when wound into a coil of any length. Bare copper wire can oxidize with exposure to the environments such as moisture, chemicals and physical abuse. Bare copper wire needs an insulation before it can work as a coil. Basically the coil would be completely shorted out and have a zero DC resistance: The DC resistance is usually measured with an volt/ohm meter. The resistance can show if a coil is working properly and even measure resistance of a coil that is shorting out internally. After years of winding you can determine if you have proper DC resistance for the number of turns you are using. If the reading is low, you could have shorted turns or magnet wire with bare insulation’s that can happen from time to time. If the resistance is high, it could show that your magnet wire is being stretched causing a higher average DC resistance for that particular gauge wire.
Number of turns: This is the number I use for the total number of turns I’ll be putting on a particular guitar or bass pickup. The winding area of a particular bobbin will determine the maximum number of turns that can be put on the coil or bobbin with a desired gauge of magnet wire.
Pitch: Pitch is the number of turns used in a given space. Like the threads in a screw will also control how fast the winding will travel from left to right within the walls of the traverse.
Traverse: The traverse is the winding distance from the left to right side of a bobbin. Most bobbins are wound vertical where the top is facing left and the bottom is facing right or vice versa. The traverse is the actual area between the inside walls of the bobbin.
Multifiler: Multifiler is usually 2 or more wires bonded together that can be wound around the bobbin at the same time. The diameter of the bonded wires will also determine the pitch of the wind.
Bondable wire: Magnet wire that has an adhesive coating that will bond by either Heat bonding by baking in a special oven or Chemical bonding as it is run through a chemically saturated felt wick as the coil is being wound. The coil can also be chemically sprayed with a mist application as it is being wound.
Wire shaping: Magnet wire can come in several shapes with the standard round copper, rectangular and square magnet wire. The ribbon and square magnet wires are used for special applications such as speaker cones and would be difficult to wind on a pickup.
Automatic traverse: As the bobbin is turning when being wound, the traverse automatically travels back and forth to the desired pitch or speed. The traverse usually works in relation to the winding speed of a particular bobbin being wound and magnet wire diameter being used.
Scatter/hand winding: As the spinning coil is being wound with a particular gauge of magnet wire, the winder hand guides the wire back and forth to form a desired coil shape and pitch. You can watch the turns fill in between winding layers and this is how the majority of vintage Fender and G&L bobbins have been wound. Many companies still use the scatter or hand winding for the mystique and tone.
Potting: There are several types of potting solutions. There are many types of wax solutions with various temperatures and hardness. The epoxy type are used in many situations along with varnish that you can bake or let air dry too. Silicone is used at times and basically the various potting solutions are used to help eliminate unwanted microphonic feedback, tampering and circuit or coil protection from the elements.
Wind to turns: Winding to a pre-determined number of turns as most modern winding machines are set up to wind in that manor. Winding to a desired number of turns can also vary the DC resistance from coil to coil. Using the same gauge of magnet wire along with consistent and equal tension will help in keeping the coils DC resistance consistent.
Wind to DC: When a coil is wound to a desired DC resistance. This takes more time but with proper winding and tension, this can be done without much trouble. Winding to the desired DC resistance can alter the number of turns used from coil to coil.
Applications: Using the desired magnet wire for the right application. This could be using the proper insulation for color or diameter for restoring a vintage pickup. Even though the magnet wire would work, I wouldn’t use Green insulation for a vintage coil. I would either use Plain Enamel or Formvar depending again on the application.
Chemical properties: Usually materials that insulate the magnet wire and other chemical solutions needed to withstand contamination of outside elements such as potting by wax or other insulating varnishes.
Solderability: Amount of heat and time required to reduce insulation when soldering magnet wire. Many insulation’s are best physically or chemically stripped to expose the bare copper wire.
Windability: Magnet wire is manufactured with a lubricant to reduce friction for better de-reeling and more compact coils with better coil electromechanical values.
784. How do you determine the total layers of magnet wire in a coil?
When you have determined the winding area such as traverse width and wall height you can determine the total layers. If your bobbin has a .250 inch traverse and .230 inch wall height and you use nominal 42 gauge wire that has a diameter of .0028 inch. Divide .250 inch by .0028 inch and you get an average of 89 turns per layer. Now divide .230 inch (wall height) by .0028 inch and you get an average of 82 turns that is actually the number of layers on that bobbin. If you multiply 89 (the turns per layer) by 82 (the total layers) you would get 7298 turns. This is the maximum number of turns providing each turn was placed side by side and directly on top of each other and the magnet wire was exacting tolerances.
785. What is turns per layer?
The turns per layer is determined by the traverse width from left to right and the diameter of the particular gauge of magnet wire. Just divide the traverse area by the diameter of the wire and you’ll get the maximum number of turns that will fit side by side in each layer.
786. What is winding speed?
The winding speed is the rate at which the bobbin turns either top coming or top going. The winding speed also determines the rate at which the traverse will automatically follow the set pitch for the magnet wire diameter.
787. What is winding tension?
Winding tension is the amount of drag or rate the magnet wire can be pulled through the tension devices without stretching the wire. It is usually measured in grams for the finer magnet wires.
788. Do pickups have the same phasing from guitar to guitar with two or more pickups?
The winding direction, magnet polarity and hookup can be different from guitar to guitar even with the same brand or model. Most companies that make humbuckers usually wind the coils in the same direction, use the same magnetic polarity and are hooked up the same. Often when you want to replace a pickup in your instrument and you find out that the pickups are out of phase. I’m sure some large companies get upset with all the after market products but it sure helps sell their products. I enjoy my Jeep 4-wheel drive and often look for after market accessories to customize it.
789. Can humbuckers be hooked up differently than in series?
Typical Gibson, Duncan, DiMarzio have wiring options besides being hooked up in series. Most companies manufacture pickups with 4 conductor wiring. This will enable you to split, phase, parallel, series and many other wiring combinations when used by itself or in combination with other pickups. There are many new switches on the market and some fancy wiring diagrams.
790. Can I reverse my Strat pickups 180 degrees to get more output out of my B & E string?
The majority of instruments manufactured by Fender have the traditional routing in the body and trying to reverse the pickups 180 degrees won’t fit. You would need a larger cavity or a pickup that has a oblong bottom plate like a Fender Jaguar. Some after market companies can make a reverse staggered pickup just for that purpose. You can also ask your rewinding service to reverse the pattern for you. It can easily be done with good results.
791. Can I wire two pickups in series?
You can usually put the finish of one coil to the beginning of the next coil and you will have two pickups in series. Providing they are both wound in the same direction and have the same magnet polarity they will have proper phasing. If you ground the beginning from both coils and make both finishes a hot connection, the two pickups will be in parallel. When the two coils are connected in series you can add a switch to the middle to split the two pickups making only one operative. The older Fender Duo-Sonics from the late 50’s had two pickups hooked up in series for a unique tone and blend of pickups. I have an old ‘57 Duo-Sonic guitar and love the pickup combinations and tone possibilities.
792. Can pickup phasing be effected by reversing the wires? Reversing the magnetic field?
By reversing the hookup wires from ground to hot and hot to ground the pickups will be electrically in or out of phase when used in combination with two or more pickups. By reversing the magnetic field 180 degrees, the pickup will either be magnetically in phase or out of phase when used in combination with two or more pickups.
793. Can the hookup be changed for phasing the pickup?
Many times the hookup wires on a single coil pickup can be reversed to make a pickup in-phase or out of phase when used in combination with another pickup. Another problem when reversing the hookup wires especially on a Stratocaster pickup, is the poles become noisy if touched and can short out if accidentally touched by the grounded guitar string. Fender Mustang guitars that use a slide switch for each pickup has a solid cover over each pickup so the poles don’t become noisy. Telecaster lead and rhythm pickup need to have the ground lifted if you want to reverse the phase in each pickup. The ground wire is also the beginning on Fender Telecaster pickups and reversing the wires would make the entire ground of the guitar become noisy and buzz when touched.
794. Can the pickups on my Strat be reversed so I can get the Jimi Hendrix sound?
Depending on the type of cavity and how it is routed in your Stratocaster body will determine the type of pickup you need and how the pickups will fit. The traditional cavity route will not allow the pickups to be reversed in your Strat. The shape of the fibre or molded bottom on the pickup fits the shape of the cavity. The pickups will not physically fit into the instrument. You would need to use a staggered Strat style pickup that has a parallel sided bottom plate similar to a Jaguar pickup. This will allow you to reverse the stagger in the pickup and changing the pole piece height under each string. Jimi had this same effect by playing a right handed guitar and reversing the strings and playing left handed. The normal right hand pickups are up-side down with different with reversed strings over each pole. One important thing that helped Jimi’s sound was that the bridge pickup was now at an opposite angle. The pickup is now slanted farther away from the bridge on the treble string side and closer to the bridge on the bass string side.
795. Can the pickups on my Strat be wired like a humbucker, in series?
This type of wiring was done on early Duo-Sonics during the late 50’s. This was done with a special toggle switch that would put the two pickups in series. The pickups were also reverse wound and reverse polarity to each other and this combination made the two pickups hum-canceling. This same wiring can be done with modern switches and this information will be shown in future articles along with many custom wiring diagrams.
796. How can I fix my pickups that are out of phase when used with another pickup?
You can fix the phase of pickups in two ways:
First, you can magnetically change the polarity on one of the two pickups by physically reversing the magnet 180 degrees or remagnetizing the magnet with opposite polarity either from North to South or South to North. You will usually change the magnetic calibration which can change the sound of the pickup after you remagnetize it. If at all possible, try to physically reverse the magnet polarity by reversing or flipping over the magnet used in most humbuckers as long as the pickup isn’t epoxy potted. It is difficult to reverse magnets in single coil pickups when they are pressure fit into the flatwork and the magnet wire is wound directly against them. By removing the rod magnets will break the inner coil windings. If you have a molded Fender style bobbins and the rod magnets can be easily moved up and down, just slide them out and flip them over 180 degrees with no damage to the coil.
Second, you can reverse the lead or hookup wires to correct phasing in most cases. This electrically changes the currents direction within the coil or combination of coils. Humbucking pickups that use two coils can be electrically out of phase if incorrectly hooked up. Normally both coils are wound in the same direction. If they are both wound top left-top coming with both finishes wire hooked together and the beginning wire on the adjustable bobbin is grounded and the beginning wire on the non-adjustable bobbin is connected to the hot or positive lead wire in the circuit. By reversing the beginning and finish lead wires in a system can cause the pole pieces in single coil pickups to become noisy and can cause the system to short out if it accidentally touches ground.
797. How can I fix epoxied pickups that are out of phase?
If you have a humbucker that’s epoxied it is more difficult to reverse the phasing. If you have single conductor shielded wire, you can sometimes do some fancy wiring by reversing the ground and hot leads. Using special magnetizers with custom probes or pole pieces enable you to remagnetize the magnet within the epoxied pickup and reversing the polarity. If you have two or four conductor hookup wire will allow you to do some custom wiring.
798. My humbucking pickup reads about 8 k ohms but sounds real thin like a banjo. What can cause it to sound like that?
It sounds like one coil is out of phase with the other in the humbucking pickup. Basically take one coil and reverse the leads connected to the second bobbin. If you are using a mini-toggle switch or it has 4 conductor wire make sure that you are using the correct wiring chart for that particular pickup. Most companies that make pickups use the same color coding but some use their own which makes pickup wiring a guessing game at times. Also make sure the bobbins are both wound in the same direction and both finishes are hooked up together. Then make sure the beginning of one bobbin is grounded and the other is hot. If the pickup sounds great by itself and now is out of phase with another pickup, reverse the ground and hot beginning wires coming out of the pickup.
799. How can I fix the phase from pole to pole on my single coil pickup?
I’ve seen single coil pickups with rod Alnico magnets that had opposite magnetic polarities from pole to pole. Either someone rewound the pickups and accidentally put the poles in upside down or the poles were magnetized first then pressed into the flatwork. Having magnetized magnets while assembling the bobbin can cause several problems. It can cause phasing problems from pickup to pickup and within a single pickup. Pre-magnetized rod pole pieces can pickup up debris especially when grinding the magnet to put a chamfer on one end.
800. How can I remove all the debris such as steel wool and other metallic objects that cling to my pickups?
I often get pickups in that look like they have been used to pickup debris from the bottom of the ocean. To loosen the ferrous debris you need to remove the magnetic field they the objects attract to. On humbuckers it is easy to remove the bar magnet and use compressed air to blow away the debris from the pole pieces and around the bobbin. You then need to use a fingernail brush or old tooth brush to remove the debris from the bar magnet. I’ve used masking tape or carpet tape to collect the debris from the bar magnet. I’ve had some pickups with non-removable magnets that were so bad that I demagnetized all the magnets to get rid of steel wool from all the nooks and cranny’s.