426. What is "Dun-aged"?
This is a process I developed to calibrate various bar and rod magnets to a desired field strength. I artificially age or degauss magnets to obtain a certain tone and output from a pickup. I like winding vintage coils and using very weak magnetic fields. It helps soften the sound of an instrument that may be very bright sounding acoustically.
427. What is a sand cast magnet?
This mainly refers to the Alnico family of cast magnets. Sand molds are made where the molten magnet material is poured and when cooled the hardened surface takes on the imprint of the sand mold in which it was poured. The fine rough surface is often surface ground to a desired tolerance or surface finish.
428. What is a ceramic magnet?
Ceramic magnets are also known as sintered ferrites and are composed of barium or strontium ferrites. Some ceramics can be unoriented or oriented and basic ferrites are made into slurry and pressed (sintered) into shape, fired in an oven and forced air dried at 100? C. After the magnets are completed they are cut or ground with wet diamond wheels for desired tolerances. Ceramic magnets can be shipped magnetized or unmagnetized. Ceramic particles can be imbedded into rubber or vinyl and can be used for refrigerator magnets and even magnets like the ones found on various models of Rickenbacker bass and guitar pickups. Ceramic magnets are often used on distortion and hotter pickups.
429. What is a cobalt magnet?
A cobalt magnet is actually a magnet made of 36% cobalt steel as used on the early Gibson ES-150 or commonly called the Charlie Christian Guitar and the EH-150 or Electric Hawaiian. Cobalt is also one of the elements used in various grades of Alnico magnets. Al (Aluminum) Ni (Nickel) Co (Cobalt)
430. What is a dipole?
It is a system of two equal and opposite electric charges and have magnetic poles that are separated by a small distance and any molecule can be an induced if exposed to other external fields and they can align a dipole most of the time.
431. What is a domain in a magnet?
All ferromagnetic materials contain regions that are microscopic and are called domains by which all magnetic moments are aligned. They contain 1017 to 1021 atoms and the boundaries between the different orientations are called domain walls and when unmagnetized the domains are at random and have no specific magnetism at the moment.
432. What is a magnetic pole?
A magnetic pole is a magnet with a North or South seeking magnetic field. If you break a magnet in half, it will have another North and South seeking pole. In other words, each magnet will have its own North and South poles. No matter how many times you break a magnet in half, it will have its own North and South poles.
433. What is a rare earth magnet?
A modern samarium-cobalt is a rare earth magnet and a manufactured into a dry powder and then pressed into basic shape with a strong magnetic field and sintered under high pressure and are oriented. You cant make the samarium-cobalt magnets into many shapes and is limited in size.
434. What is a sintered magnet?
A sintered magnet is the mixture of aluminum-nickel-cobalt and iron (Al-Ni-Co) that is formed under high pressure for making commercial grades of sintered Alnico 2 (unoriented) and sintered Alnico 5 & 8 (oriented) magnets and another process is used for making sintered ceramic magnets. Sintering is done on smaller size Alnico magnets to produce a better surface, high tensile strength and better homogeneity. The sintered Alnico magnets are oriented after sintering and are usually demagnetized for grinding and shipping.
435. What is an Alnico magnet?
An Alnico magnet is made from various element combinations for different grades of Alnico. Alnico magnets were developed by G.B. Jonas in 1939 and his patent for Alnicos is 2,295,082. Cast Alnicos is a combination of Aluminum, Nickel, Cobalt and Iron as a filler. There are around 12 grades of Alnico with both Isotropic and Anisotropic orientation. Alnico magnets are used in the majority of vintage Fender and Gibson pickups. Cobalt Steels such as 36% were used on the ES-150 pickup. Alnico magnets were used because of availability.
436. What is an Anisotropic magnetic field?
Anisotropic is the desired direction of the magnetic field and is often indicated by the sign ¨MÆ. The ¨MÆ indicates that one side of the pointing arrow has a North seeking magnetic field and the opposite arrow indicates a South seeking magnetic field. Trying to magnetize a magnet other than indicated will make the magnet inefficient.
437. What is ferromagnetic?
A material that is attracted to a magnetic field such as a guitar string made of spring steel and wrapped with a desired outer wrapping. The vibrating ferrous string disturbs the magnetic field and induces a current in the pickup that is sent to the amplifier through a variety of controls to blend, enhance the signal and tone.
438. What is an Isotropic magnetic field?
An Isotropic magnetic field is a magnetic field where the properties are the same in all directions. Rod magnets are normally magnetized with one end North and the other South and have an Anisotropic magnetic field. Bar magnets can be made to be Isotropic and can be magnetized in several directions.
439. What is magnet flux?
Early magnetic investigators attempted to describe the magnetic fields present in magnets. The invisible force field or magnetic field that travels through the air and when moved through a coil produces or generates a alternating current. The field travels from North to South through a magnetic circuit.
440. What is magnetic calibration?
Calibration of a magnet is to reduce the level of magnetization to a predetermined or custom strength of a particular magnet. Alnico magnets are my favorite to calibrate and I can control the amount of magnetic field to the strings. I feel you dont need all the magnetic field you get from certain Alnico magnets and controlling the calibration can give you many custom sounds and tone from your pickup.
441. What is a magnetic keeper?
A pickup actually uses the strings as a keeper with an air-gap in between the poles. A keeper is usually used on a horseshoe magnet to complete the magnetic circuit. A keeper is not a working part of a magnetic circuit but it keeps the circuit stabilized when not being used for any specific purpose. A keeper is usually any ferrous material that will allow the flow of magnetic field through a circuit.
442. What is magnetic phasing?
I usually use this term when two or more pickups are used with a combination of switches or custom circuits. If two pickups are both wound in the same direction and both have the same top magnetic polarity, the pickups are electrically and magnetically in phase. If both pickups are wound in the same direction and one pickup is North polarity and the other is South polarity, the pickups are magnetically out of phase.
443. What is the "Dun-Stunner"?
This is another device I built to calibrate or shape the magnetic field within a coil or pickup. I use the Dun-Stunner to calibrate the magnetic field within coils already installed in a pickguard assembly and intentional reduction of a magnetic field.
444. What is the diameter of older magnets vs. the newer Alnico rods?
Many of the early magnets used on Fender instruments had a rough surface sand cast magnet with an average diameter of .197. The larger diameter magnets were used from early to late 50s. The standard size became .187 in diameter. The early magnets were raw with rough sand casting pits. The outer surface had a darker color and brighter when surface ground. The magnets fit quite tight into the early vulcanized fibre flatwork and many pickup have amazing longevity even with all the years of use and abuse.
445. Where is the magnetic field in a guitar or bass pickup?
Generally the magnetic field in a pickup is where the pole pieces are located either in rod or bar magnet or in a ferromagnetic material such as the steel screw pole pieces that are strongly attracted to the screws which direct the magnetic field to the strings. The magnetic field can be attracted to the mounting screws on the bottom of a pickup thats used to secure the bobbins to the base plate. If they are ferrous, they can pull the magnetic field away from the pole pieces directly under a string. Many pickups use ferrous height adjust screws that can affect the magnetic field. Any ferrous material in or around the pickup will affect the magnetic pattern in the magnetic circuit.
446. How do you measure the gauss in a magnetic field?
In our lab we use electronic gauss meters for precise measuring of the various magnetic fields used in our pickup. When I do road trips I like using a small hand model manufactured by the R. B. Annis Company in Indianapolis, Indiana. The unit I use measures from -50-0-50+. The -50 is the South magnetic polarity and the 0 is neutral or no magnetic field and the 50+ is the North magnetic polarity. This handy gauss meter helps me determine the magnetic phasing of pickups along with magnetic calibration that we perform at my shop.
447. What is the magnet polarity of various other pickups?
The magnetic polarity of pickups can either be South or North. Ive seen early Fender pickups with both South and North polarity in the same guitar. Early Broadcasters, No-Casters and Telecasters were often made with pickups having different polarities. The early lever switch on the instruments didnt allow the combination of both pickups and the phasing didnt matter. The majority of the early Stratocaster pickups had a North polarity and later changed to a South polarity. Early Gibson humbucking and single coil P-90 pickups are usually South polarity at the adjustable poles. On various Gibson stereo models, the neck pickup is often made North polarity but the pickups are out of phase when used monaurally. Many players want to convert the stereo models by rewiring it and all you need to do is flip the magnet over within the pickup.
448. What is the magnetic orientation of a magnet?
The magnetic orientation of a magnet is the preferred direction of the South and North polarity. The rod magnets used in Fender style single coil pickups are South on one end and North on the other. The bar magnets used in Gibson style humbucking pickups designed by Seth E. Lover, the magnet measures 2 1/2 long x 1/2 wide and 1/8 thick and is magnetized across the 1/2 dimension. Some believe the magnet is magnetized along the length but this would make the pickup work improperly. Normally the stud side of the humbucker is a North polarity and the adjustable side is the South polarity. Magnets can be reversed as long as you like the sound when two or more pickups are used together. In single coil pickups you need to use the same polarity on all the rod magnets in a row. If one or more are reversed, there will be a phase problem within the pickup and combined with others. with others.
449. What is the technical specifications for Alnico, Ceramic & misc. magnets?
I would suggest reading Pickup Questions 52 in Vintage Guitar and many of my articles list information about the various magnets and specifications. Magnets can add magic to a pickup and is so important to the tone and output as well as the gauge of magnet wire and number of turns. All have tolerances and when combined to a magic piece of wood can create the many desired tones from Jimi Hendrix, Albert Collins, Jeff Beck, James Burton, Roy Buchanan, Danny Gatton, Eric Clapton, Gary Moore, Paul Kossoff, The Ventures, Arlen Roth, Albert Lee and the many thousands of guitarists who weve listened to. They have the tone and the technique to create sounds out of the instrument using their fingers and picks. Also dont forget that the speakers, microphones, earphones and our radio speakers all use magnets to re-create the great tones produced in the studio. Magnets are musical and when combined with electricity can create music so great to our ears.
450. What will changing a magnet in my pickup do?
Changing the magnet can do several things depending on the magnet your replacing it with. If the magnet is stronger than the replaced one the output can be greater and brighter sounding. If the magnet is weaker than the original, the output can be less and the sound will be warmer. Often remagnetizing a row of single magnets or a bar magnet will make the sound brighter and harder sounding. If the magnetic field is too strong the notes can sometimes sound like glass shattering. Putting in strong ceramic magnets will make the pickup louder and brighter but will also dampen the string vibration and sustain. The strings can stick to the pole pieces when doing dive bombs with your whammy bar. I like to tone you get with weaker magnets and I spend much of my work week calibrating magnets for a desired tone.