Magnet material:
grade
The magnet material comes in several grades and dimensions. Earlier articles in VGM show various grades of magnetic materials
supplier
Depending on what supplier the fabricator gets the raw stock before grinding and cutting will determine the quality and standards used in making the magnet.
how magnetized
Magnets can be magnetized by several methods: discharge, inductors, impulse and in contact with other magnets.
calibration
Depending on the material and amount of ampre turns needed to magnetize the material to full saturation. Using lower ampre turns will not fully align the domains in the magnet and magnetizm will not be fully achieved. Calibration is determining the precise amount of magnetic field needed for a specific application and done with the use of calibrating inductors.
age
The age of the material will have an effect on the magnet with natural loss of magnetic gauss or strength.
enviormental effects
Heat, shock and electrial interference can de-gauss the strength of a magnetic field within a magnet
magnet polarity.
Magnets can have a north or south polarity on either end or specially magnetized for specific magnet designs or shapes.
Bobbins specifications:
flatwork thickness
Depending on the flawork thickness will do several things. The thicker the top flatwork on a bobin will add strength to support the coil windings but also keeps the coil further away from the strings. Thinner flatwork allows the pickup to be raised closer to the strings especially when covers are used. Thinner top flatwork that has great pressure from the wound coil can lift and warp under hot and humid conditions.
pole spacing
The pole spacing can be different from guitars made in Japan, Europe and the US
Manufactures use different methods of measurement such as metric and English conversions. Pole spacing can be different from Fender spaced, “F” Spaced or Trem spaced and to Gibson Spaced. Bar and blade pole pieces are used to accommodate the various string spacing on guitar and basses.
traverse
The traverse is the winding width of the coil or the distance back and forth when the coil is wound. The spacing determines the maximum number of turns of a coil when wound side by side in a given area.
pole arrangement
The pole arrangement can be either steel screws to conduct the magnetic field to the strings or rod magnets either flat or staggered. The pole piece can be a blade, steel rod, magnet rod or bar, steel blade or combination of blades or any ferrous material to conduct the magnetic field to the strings.
bobbin material.
The bobbin material adds to the stability and shape of the coil form. Molded bobbin are generally more consistent than bobbins with fabricated flatwork. The majority of Fender style flatwork is made from the Vulcanized Fibre which is compressed paper and very vulnerable to moisture and exposure. Plastic based materials used for humbucking bobbins is more durable to long playing as long as styrene plastics are not used for bobbins as it will wear away exposing the coil and possible damage.
Winding specifications:
magnet wire gauge
Magnet wire comes in a number of gauges and insulation thickness. The normal wires used for guitar and bass pickups are 42, 43, 44. The larger the number or AWG, the bare magnet wire diameter gets thinner. The thinner the bare wire the higher the DC resistance for a given length as compared to 43 which is lower than 44 and 42 which is lower than 43 gauge of magnet wire.
bare wire diameter
Magnet wire is drawn to a precise bare diameter dimension before insulation is added. If you wound a coil with uninsulated magnet wire the coil would completely short out across the beginning and finish of the coil. The coil wouldn’t induce an alternating current needed to produce a signal to the amplifier. Magnet wire come in Minimal, Nominal and Maximum outside diameter (OD) before the insulation is put on to the desired thickness or layers.
insulation thickness
Insulation is put on in layers and dried in heating ovens. Several layers can be added depending on the build needed for a specific use. If AC or DC current is used than a thicker insulation is used when higher current or heat is a factor. Normally guitar pickups don’t produce heat and thinner insulations can be used allowing more winding room within the bobbin or coil form.
ohms per thousand feet
I measure ohms per thousand feet to get a better average on the magnet wire used. I mark all the spools to better keep coils within a specific winding and DC resistance. I measure 10 feet of magnet wire and mutiply it by 100 to give me ohms per 1,000 feet. I have a magnet wire chart and it will tell you what the “American Wire Gauge” (AWG) is. You can determine if it’s closer to a lower gauge or a higher gauge.
number of turns
The number of turns does several things. It tells you the DC resistance or ohms of a particular coil. It determines the inductance in henries of a coil along with “Q”. The number of turns determines how much output the coil will have in relation with the magnetic field and proximity to the strings. Generally the more turns decrease the highend on the pickup. The less turns increase the highend or brightness in a pickup.
number of turns per layer
Winding machines that have an automatic traverse control when pre-set for the diameter of the magnet wire determines the pitch of a wind the the threads on a screw. The faster the pitch decreases the turns per layer and the slower the pitch allows more turns per layer. The maximum number of turns side by side of a coil is determined by the overall diameter of the magnet wire including insulation. Winding over the maximum desired number of turns per layer begins to stack and bulge the coil. This usually happens when a pickups is scatter or hand wound. The traverse control automatically travels back and forth at the rate of the pitch setting.
number of layers
The number of layers is determined by the number of turns per layer and the total turns of the coil. For example if a coil gets 8,000 turns and there is a 100 turns per layer then there would be 80 layers. The pitch or distance between each layer determines the inductance of a coil.
automatic layering
Automatic layering is the same as automatic pitch control and info given under “number of layers per turn”. Automatic means it is done by mechanical means other than scatter or hand winding.
scatter winding
Scatter or hand winding is where you guide the magnet wire being wound on the coil back and forth by hand. As the motor speed and direction determines the coil being wound, it will also determine the tension and electrial phasing.
tension
Magnet wire being wound and held by mechanical or by hand will determine the tension on the coil. Tension that is too high will stretch the magnet wire and increasing the DC resistance and possible cracking and shorting of the insulation. Winding a coil with too much tension can warp and flair the bobbins.
winding direction
The winding direction of a coil determines the phasing electrically when combined with a north or south magnetic field. If two pickups have the same magnetic polarity facing the strings and one coil is wound top coming and the other is wound top going then the two pickups will be electrically out of phase.
Pickup placement:
distance from bridge or neck
A pickup moved closer to the bridge will sound brighter but will have less output due to less string vibration. Moving the pickup further away from the bridge will sound less bright, fuller and more output. Watch a guitar string and you’ll see the string vibrating more over the neck pickup than the bridge pickup even though the two pickups may be wound identical.
distance from strings
The closer the pickup and magnetic field are to the strings the more output the pickup will have. The further away the less output it will have.
Pickup circuit:
value of volume and tone controls (measure actual values, not value stamped on bottom).
Many volume and tones controls have a value stamped on the bottom such as 250K, 500K, or 1 meg. but actually measuring the pots from the #1 & #3 lug will give you the precise value. Pots used for a volume control that say 265K will make the pickup sound brighter than a pot that has a value of 235K. The manufacturer has an allowable tolerance for his manufacturing specifications. That’s why changing your controls can make your instrument sound different.
capacitors for tone circuit
Capacitors can determine how much bass your instrument will have. Make sure they are the proper value and keep to a low voltage like 25V. The standard for guitars and basses is .05 Mfd. 25Volt.
gauge of hookup wire
The hookup wire used is important for wiring instruments. Shielded wire works best for maximum reduction of outside interference. Single conductor insulated wire used for Fender style instruments should use 22 AWG stranded. Solid core insulated wire should not be used and harder to work with when making assemblies. Solid core insulated is used in most Fender amplifiers for hard wiring the circuit boards. Using wire that is to thin will increase the DC resistance in the total reading in the pickup and capacitance to the circuit. Wires should be kept at a nominal length when at all possible.
String gauge:
alloy
Strings are made from spring steel and the wound strings are wrapped with various alloys for tone and tension. Spring steel used is similar to the music wire found in hardware stores before going through the process of putting the ball ends on. Guitar and bass strings usually have a wrapping of various alloys and the string diameter is determined by the diameter of the wrapping which influences the pitch or how close each turns is wrapped. The type of alloy used for the strings will determine the magnetic attraction needed to move the magnetic field from the pickup.
diameter
The diameter is determined by the diameter of the bare spring steel and if it’s plated and diameter of the wrapping or surface condition of the string when finished. The larger the diameter of the spring steel or string guage usually increases the output of the pickup.
round wound, flat wound, tape wound, half round.
Round Wound strings are tightly wrapped with a round alloy side by side for the duration of the string over an inner core of solid spring steel. The diameter is determined by the diameter of the inner core spring steel plus double the diameter of the wrapping. Flatwound strings are wound with a flat tape alloy for the duration of the string usually over a previously round wound string that’s also wound around a solid inner core of spring steel.
Cables:
guitar cords and length.
The length and conductor used in making guitar cords can determine brightness of your instrument. Low capacitance cable the favorite of Eric Johnson allows the high end to be heard with more clarity. The length of the cord too is important to the overall sound of the instrument but it didn’t bother Albert Collins when he used his 100 foot cable to walk into the crowd.
Wood, finish, hardware:
type of wood, weight and density
The type of wood used like Alder, Ash, Maple, Mahogany or other exotic woods play an important factor on the tonal qualities of an instrument. The heavier woods tend to make the pickups sound brighter the lighter woods like Basswood and Alders tend to soften the sound of the instrument and make the pickups sound smoother. The grain of the wood or tightness of the wood will play an important factor in how the pickups react with the wood. My favorite woods are Alder for Strats and swamp ash for Telecasters.
finish
The finish used on the instrument will change the sound of your pickups making the body compress the tone and sound of the pickups. The old lacquers and enamels used years ago age and allow the instrument to breath and respond to the total vibration of the instrument. The modern plastic and water base paints don’t do the instrument justice in my opinion cause it mutes the tone of the wood like a capacitor in a tone circuit.
hardware
The hardware used on your instrument such as bridge material, plating, construction and other factors can determine the sound of your instrument and pickups. The more mass you use can drastically change the tone of the string vibration and sound picked up by the pickup. Even when using large tremolo’s for that twang can make your instrument sound thin because your not getting the body vibration working with the string. The large tremolo’s act like a radiator diffusing the string vibration. This is only my opinion and that’s why I’ve played a Telecaster all these years.