76. When I read specifications giving D.C. resistances from different pickup manufactures, I often get different readings when measuring the same pickup model. How come? Burke Lane-Woodstown, New Jersey
When pickup manufactures measure pickups for their catalogs they usually put down the average D.C. Resistance. Pickups are usually wound to a desired number of turns with a particular gauge of magnet wire. When using magnet wire from different suppliers, the magnet wire can have many tolerances such as this example: Diameter of the bare copper wire for 42 gauge of wire can be .0024 minimal, .0025 nominal, .0026 maximum. The insulation can have tolerances in several thicknesses making the total wire diameter .0026 minimal, .0028 nominal, .0030 maximum. Even though your pickup may have the same number of turns the catalog may state a pickup being 6.3k Ohms D.C. Resistance, but yours may read 6.1k Ohms D.C. Resistance. The different D.C. Resistance can change your tone slightly. The manufacturer tries to keep close tolerances when making pickups but sometimes the manufacturer winds the pickup with a wrong gauge of wire or number of turns for a particular model pickup. Sometimes it gets past quality control if not checked closely and can cause problems for everyone especially the player. When winding the pickup I use tension devices that control the precise tension on the wire. If the tension is too tight when winding a pickup, the magnet wire can stretch and cause the D.C. Resistance (Ohms) to increase. Ive often wound coils to the exact D.C. Resistance. One spool of magnet wire may take 7,875 turns of 42 plain enamel to wind a Telecaster pickup to 6.0k D.C. Resistance and another spool may take 7,945 turns to achieve the same exact 6.0k D.C. Resistance. If in doubt or have any questions about the specifications on your pickup call the music dealer or pickup manufacturer. They will be there to help you.
77. Where can I find an economical Gauss meter other than one that cost hundreds of dollars and uses a variety of probes? John Fernandez-Brick, New Jersey
A company called Micropower makes a sensitive Gauss meter with many probes for different applications but is very costly. I mentioned in an earlier article about a handy hand-held gauss meter made by the R.B. Annis Co. in Indianapolis, Indiana and their phone number is 317-637-9282. They have different scales on the hand-held model with a nice case. I use the (-50 -0- +50) scale. The minus 50 side is for (South Magnetic Polarity) and the plus 50 is for (North Magnetic Polarity). I have heard from other repairman that they work great for determining the polarity of pickups and comparing the strength of different magnetic fields in many pickups. The Gauss meters are sensitive too, so dont use them near anything that could effect the calibration of the Gauss Meter. Keep them away from transformers and those soldering guns with the big coils in them.
78. What are some of the pickups terms used in making pickups? Alphonse Kettner-Los Angeles, California
Here are some of terms I frequently use when talking pickups. I will give general answers as some can be quite elaborate. Also some of the terms will have different applications to different manufacturers.
Calibrated: I do this when winding two or more pickups to be used in one instrument. Calibration can be done with the winding or the magnetic field. Generally to calibrate the coils for various positions I use a different number of turns and/or desired winding direction for each pickup position. Winding for an instrument with two or more pickups, the bridge pickup usually has more windings than a middle or neck pickup. The bridge pickup could be wound with 8,000 turns, the middle with 7,800 turns and neck pickup with 7,600 turns in a three pickup instrument.
Top Coming: Putting the top of the bobbin facing left (TL-top left) on my coil machine, I wind with the side top of the bobbin coming towards me. The coil is wound counter-clockwise. Looking from the top of the bobbin the wire begins on the right eyelet and ends on the left eyelet.
Top Going: Putting the top of the bobbin facing left (TL-top left) on the coil machine and wind with the side top of the bobbin going away from me. The coil is wound clockwise around the bobbin. Looking from the top of the bobbin, the wires begin on the left eyelet and end on the right eyelet.
RW / RP: I use this term Reverse Wind-Reverse Polarity when winding two or more pickups. When a bridge pickup is wound TC / S (top coming-south magnet polarity) I would wind a neck pickup thats RW / RP or be wound TG / N (top going-north magnet polarity). This combination would make the pickups humbucking when both used together.
Polarity of a pickup: A single coil pickup can be wound four (4) different ways. I generally put the top of the bobbin facing left (TL) on the coil machine.
1. Counter Clockwise Coil (TC) with a South Top Magnetic Polarity
2. Counter Clockwise Coil (TC) with a North Top Magnetic Polarity
3. Clockwise Coil (TG) with a South Top Magnetic Polarity
4. Clockwise Coil (TG) with a North Top Magnetic Polarity
Polarity: The relationship of positive and negative electric currents or north or south magnetic fields to each other.
Series: The electrical linking of two or more coils in series connection. If two coils were each 4K Ohms then in series they both would equal 8K Ohms. Coils in series produce a higher output and fuller more powerful sound. This is the standard hookup for a Gibson style humbucking pickup.
Parallel: The electrical linking of two coils in a parallel or side by side fashion. If two coils were each 4K Ohms then in parallel they would be 2K Ohms or the added average of both coils divided by 2. When a pickup is in parallel with its self like a humbucker, the high end is cleaner, less output and still humbucking if wired properly.
Out of Phase sound in a Stratocaster: I always hear this in reference to Stratocasters in the # 2 or #4 position of the 5-way lever switch. The pickups are actually in phase but parallel with each other. Both beginning or ground wires on the pickup are connected to ground on the volume control, and both hot or lead wires are connected together by the blade on the lever switch. Both are connected at the same time to the hot terminal on the lever switch thats connected to the # 3 lug on the volume control.
Out of Phase: Opposite linking either magnetically or electrically in one or more coils used together. Two coils or two pickups in either series or parallel but with the signal polarities summed in such a way as to provide partial cancellation of the signal. Usually the low frequencies are canceled so the resulting sound is thin lacking in warmth, quite brittle and making a guitar sound like a banjo.
Split Pickup: Usually done with Humbuckers and when grounding the series connection between the two coils, shorting out one of the coils leaves only one coil operative. This is done in Humbuckers to achieve a single coil sound. By reversing the ground and hot connection on the pickup can reverse the coil thats operative. When the series connection is grounded in a standard Gibson humbucker the adjustable coil is operative. If the hot and ground wire are reversed the stud coil becomes operative. The stud side of the coil usually has more output because it has a more direct and stronger magnetic field to the string. The adjustable poles extend the magnetic field out the bottom of the pickup.
Tapped: A coil that is wound with various output or connections for different frequencies and output. A coil can have two or more wires that can be used for different switching and tonal combinations. I first made tapped pickups when working at the Fender Soundhouse in London, England during the early part of 1974. I can wind a pickup to a stock wind of 8,000 turns and add 3,000 turns more. You can wind a coil to 7,000 and stop at the stock wind of 8,000 turns. You can add turns to the stock wind, tap using smaller gauge of wire, or tap as many times as you like. You can reverse the beginning and finish wires and have different a degree of a tapped coil. I have tapped coils running one lead to one amp and the other tap to another. You can have stereo with different frequencies. You can do some fun experimenting with this.
Passive Pickup: An instruments pickups which uses no internal active (pre-amp) electronic circuitry. A passive pickup that goes from a switch, volume control to a jack is typically a passive circuit.
Active Pickup: A pickup with a circuit board built within, to create a desired output and frequency such as an EMG pickup that work well and are quiet. Other types of Active pickups have external circuit boards and pre-amps to give a desired tone and output. A preamp is used to achieve gain enhancement, tonal shaping and to gain or lower output impedance. Active pickups are used to retain loss of high end usually associated with driving long cables. They are useful for producing the strong noise free signal needed to drive multi-effects.
Stack Pickup: Our patented technique of stacking two coils, one above the other in order to cancel hum and noise but retain a single coil attitude to the string. This technique can be done using bar magnets, ferrous blades, or rod magnets for pole pieces. Each coil has a north and south polarity to achieve a humbucking effect when the coils are in series or parallel.
Pole piece: Creates a magnetic path to the strings. Many shapes and materials have been used for getting the magnetic field to the strings. As the string is magnetized and moves, the moving magnetic field flows through the coil and generates an electrical current which is sent to the amplifier and amplified many times. Pole pieces have been rod magnets such as on Fenders, Bar magnets such as the Gibson Melody Maker, Steel rods and adjustable screw as on a Gibson P.A.F. humbucker, laminated or solid ferrous blades used on Gretsch pickups. Many with permanent magnets inside to magnetize the ferrous material or desired path that directs the magnetic field to the strings. Others with ferrous cores that have fingers within the bobbin such as the Lace Sensors. Magnet rods and bars can be made of various alloys and degrees of strength that alter the tone, string pull and output of a pickup. Pole pieces come in many types of screw such as Slotted head, Pan head, Fillister head, Hex and Socket head, Round head (slotted and Phillips). With the many designs that are developed and ones to be developed you will be assured of the many new and upcoming
pickup designs. The physical configuration of the pole piece will vary the magnetic field intensity of the pickup.
Humbucking: A pickup that is usually comprised of two coils wired in series or parallel that eliminate unwanted electrical and magnetic interference. The two coils are summed electrically out of phase and with opposite magnetic polarities. The effect of the configuration is to cancel hum and other extraneous noise and leave the string signal intact. Note: When removing humbucking pickup covers you let in unwanted signals that the coils cannot fully eliminate.
Ground: The common reference point in an electrical circuit. Usually the controls, switches, pots, and beginning wires from pickups are grounded. Usually single coil pickups have the beginning wires connected to ground. If the coil is wound and directly touching the pole piece, and the beginning wire made hot, you would hear much buzz and noise from the pickup.
Inductance: The property of a coil to oppose changes of current through itself.
Potting: Means by which you saturate the coils, hardware in a pickup to eliminate unwanted vibrations that cause squeal, feedback or other howling noises generated from the pickup. There are several types of potting solutions, wax being the most common and allowing the pickup to be repaired or rewound easily if necessary. Epoxies and varnishes give permanent and often damaging solutions to potting. If the epoxy dries with considerable shrinkage, the coil can be broken internally and non-repairable (in most cases). This may not show up for many years as I have seen pickups just stop working. Many manufactures have changed their potting techniques and solutions. Epoxy is often thicker than heated waxes and cannot always permeate the finest air gaps. Thicker potting solutions can leave open cavities unless used with a sophisticated and often costly vacuum systems. Winding can also be done with alcohol or heat sensitive bondable magnet wire. I dont like using bondable wires as they dont always insure feedback elimination in a pickup. Try and repair a pickup wound with bondable wire...Its like a solid piece of copper. Both my friend Lindy Fralin (who is a great winder) and I feel the same way, when you want to restore a pickup, you want to restore it, make it look like it hasnt been repaired. So pickup manufactures, if you want your pickups around for a long time, ones that can be fixed and restored please do not use the Epoxies or Bondable wire. Their good for transformers but not for repairman. For further information see my earlier article Pickup Question # 2, I talked about potting standard Fender and Gibson pickups.
D.C. Resistance: Usually measured in Ohms with an analog or digital meter, resistance is used for check to see if the coil is operative and what the coil reads in Ohms. Usually when a pickup has a higher reading you usually associate it with being hotter. The higher D.C. resistance tends to be louder and less bright.
79. Why are magnets on Fender pickups sometimes rough and pitted, ground on one end or slightly rounded on each end? Can I get back issues of Pickup Questions? Tapio Peltonen (Luthier) Helsinki, Finland
The Alnico rod magnets used to make the pole pieces on many single coil pickups are first cast in sand. Rods are pushed into the sand removed. Then the molten magnet material is poured into each hole which is about 10 deep. As the magnet material hardens it is removed from the sand at about a .197 diameter. On older Fender pickups you can see the rough outer surface. Magnets on newer Fender pickups have the magnets ground to a diameter of .187 and the surface is ground smooth. Magnets are cut to length with diamond blades and some vendors cut several magnets at a time. The cutters are similar to precision fret saws that can cut all the fret slots in a fingerboard at one time. Magnets used in early Fenders had one end chamfered (grounded slightly) to guide the pole pieces into the flatwork (vulcanized fibre) without reaming or enlarging the holes. The chamfer would help guide the magnet rod keep the flatwork tighter to the magnets. When winding if the flatwork was loose you would have a problem with the coil changing shape as the bobbin is being wound. I have seen many tops (flatwork) pop off the pickup if it is too loose. Magnets that look slightly rounded on each end is usually due to the magnet slugs being tumbled or deburred. This makes the ends of the magnet smoother and allows the magnet to be inserted into the flatwork easier. Magnets are tumbled because they can be done in large quantities at a time verses end grinding which is usually done one magnet at a time. When your making hundreds of pickups a week in production it may be necessary to find shortcuts in manufacturing. If your looking for back issues of VGM, please contact the magazine as they be able to help you.
80. Does changing the shape of the pole piece make the magnetic field work differently? Michael Kenny, (tech for Iron Maiden) London, England
I have experimented with many ways to direct the magnetic field to the strings and have found that using different pole piece shapes can change the way a magnetic field leaves the pickup. Seth Lover who invented Humbucking Pickup for Gibson in the 50s also worked for Fender during the 60s and spent time developing the shape of the polepiece used on the Fender Rhodes Piano. He showed me several designs and felt a tapered polepiece worked best. Different shapes will direct the magnetic field to the string and many shapes have been used by many different pickup manufactuers and many models have been developed throughout the years.
Types of common polepieces and basic examples are:
Steel blades (Charlie Christians)
Magnetic blades (Gibson Melody Maker & Firebirds)
Magnetic rods (Fender single coils)
Magnetic rods- threaded Cunife magnet (Fender Humbuckers)
Ferrous rods- (non-adjustable or stud side of Gibson humbuckers)
Ferrous screws- (adjustable side of humbuckers, Gretsch Filtertrons etc.)
Pole pieces can be fixed or non-adustable, adjustable in one coil or both similar to Gibson humbuckers or Gretsch Filtertrons, staggered poles like vintage Fender Stratocaster pickups, pole pieces flush with the top of the flatwork, raised above the flatwork, extending below the pickup or flush with the bottom of the pickup. Polepieces direct the magnetic field to the strings in many ways and all have an influence on the final sound of the pickup. Pickups can be adjusted up and down and some even have been made to slide from the bridge to the neck all give the guitar many tonal variations. Remember if you experiment with your instrument always make schematics, take measurments and notes on where you started from.
81. Will dipping a guitar pickup in hot wax change the magnetic field, as you said in an earlier article, heat can effect the magnet? Lee Goldblatt, Washington, D.C.
There are several steps you can use to wind a pickup. The bobbin can be magnetized first, wound and wax dipped or wound, wax dipped and then magnetized. When doing the second way it gives me better control when calibrating and measuring the gauss (magnetic strength) in the pickup. The coil and magnets can get very hot from the wax you will notice an increase in D.C. resistance in the pickup and the heat can change the gauss in the magnet. The weaker magnets are more susceptible to heat than the stronger Alnico Vs or Ceramics. I like magnetizing the pickups after their wound and potted in hot wax. Its hard to determine how hot your pickup can get and pay attention to what you are doing so the pickups do not melt or become deformed. Some plastics bobbins will warp even in low heat conditions. When potting you have to control the temperature of the wax and amount of time the pickup is potted. Some repairman use surfboard wax. When I talked to Mr. Zogs who manufactures surfboard wax south of Santa Barbara I found out about some of their waxes. They said the Tropical is the hardest and I think would be best for pickups if you need to use it. It could be pretty expensive for doing many pickups. Other waxes are Cold Water is softest (not recommended), Tacky is a sticky wax (not recommended) and Quick Humps is used on surfboards and beads up (not recommended).
82. What guitar and pickups did Rich Fifield used when recording with the group The Astronauts back in the sixties? Jim Sharp, Gibbstown, New Jersey
Recently I got a letter from Bill Wardwell who is a friend of Rich Fifield and he send along this information. Rich was the lead guitarist for the group The Astronauts back in the early 60s. In 1964 The Astronauts were playing around the University of Colorado and recording for RCA records. Guitar Player Magazine featured Richs playing on their Legends of Guitar CD series. The Astronauts reunited and played in 1988 and 89 in Boulder, Colorado. They last performed together in 1987. Rich told Bill that while playing Jazzmasters, Jaguars, Mustangs and Stratocasters in concert, all of their recordings were done with Jazzmasters, Dual Showman Amps and Fender Reverb units. In fact Leo Fender personally loaned them the first Reverb unit (ever) which he was building for Dick Dale so they could use it on their first album for RCA. Rich used a 1961 Olympic White Jazzmaster which can be seen on album covers. Here are some of their albums to look for:
Rockin with the Astronauts RCA #183
Surfin with the Astronauts RCA # 2760
Everything is A-OK RCA # 2782
Competition Coupe RCA # 2858
The Astronauts Orbit Campus RCA # 2903
Go Go Go RCA # 3307
Favorites for you RCA # 3359
Down the line RCA # 3454
Travelin Men RCA # 3733
The Jazzmaster pickups are wider and flatter compared to the Stratocaster pickups which have a brighter sound. The Jazzmaster has a warm full sound and tone and the two pickups are humbucking when both used together I like using Alnico 2 magnets and hand winding the coil for the authentic tone. My other favorite Jazzmaster sound are Walk dont run recorded by the instrumental group The Ventures featuring Bob Bogle on lead guitar. Another great Jazzmaster player was Roy Lanham who played with Roy Roger and the Sons of the Pioneer. Im sure Rich would love to hear from all you fans and players and you can write to him at: Rich Fifield c/o my address at the bottom.
83. I put new screws in my pickup and I hardly have any sound out of the pickup. What could be the problem? Chuck Miller, Fairbanks, Alaska
When buying new screws at hardware stores you have to check what you are buying. It seems the screws you bought might be plated like your old ones but the actual screw could be made of brass (non-magnetic) or stainless steel (most grades are non-magnetic). I often build pickups with dummy poles made of brass when doing custom or stereo pickups. The plated brass looks like an actual polepiece but doesnt direct the magnetic field to the strings. When buying parts for your pickups take a magnet to test the parts. For the pickup to work properly the parts must attach to the magnet.
84. Is it better to put a humbucker in the neck position with a single coil in the bridge or should I put the humbucker in the bridge position? Ali Handle, Los Angeles, Ca.
A humbucker will be fuller have more output in the neck position compared to the single coil in the bridge position. The single coil is usually thinner sounding and have less output than the humbucker. The humbucker has two coils usually side by side and picks up a larger string area. The single coil has one row and picks up a smaller string area. When you hit a string watch it. The string will vibrate more near the neck position than at the bridge. The bridge position will sound brighter closer to the bridge. Manufactures have hotter pickups that could be used in the bridge position to better balance the output of each pickup. There are Stack and Hot Rail style of pickups that will give you greater output than some standard single coil pickups. When putting humbuckers in the bridge, they can over power the single coils in the neck position. Depending how the pickup is used the single coil could be used for cleaner rhythm tones and the humbucker would be used for tones to make your neighbors dog howl.
85. How can you determine the number of turns per layer in a coil? Jack Neff-Bridgeton, New Jersey?
When I wind coils using a machine with variable pitch, I can vary the number of turns depending on the diameter of the magnet wire. When hand winding or scatter winding as I call it you will have a coil with a varied number of turns per layer. To keep coils in a production run consistent it is best to wind with a machine that keeps the coils looking and sounding consistent. Winding machines can be made to be used with gears that have to be changed for each wire gauge being used or a variable cam that varies the pitch speed. Pitch is the rate or speed in which the magnet wire is guided back and forth across the coil. The basic formula that I use for determining the pitch is as follows. Example
Traverse Divided by wire diameter equals turns per layer .5 (T) ? .0028 (single build 42 PE) = 178 turns per layer
Then I take the 8,000 turns per coil and divide it into number of turns per layer(178) and get the number of layers.
The total turns Divided by turns per layer equals total layers
8,000 (TT) ? 178 (TPL) = 44.9 (TL)
When hand winding you have to control the tension and if it is too tight when hand held it can stretch, change diameter and D.C. resistance of the coil. By not having control over the tension on the magnet wire while winding can cause several problems with the coil. You can bulge the ends of the bobbin that can pop the tops off some single coil pickups and I have seen molded bobbins crack at the ends when not properly wound. When using not enough tension the coils can become spongy, increased D.C. resistance and a coil that will squeal or feedback. In the chart below you will be given the maximum tension per magnet wire gauge and an average number of turns per inch.
* Magnet Wire (AWG): is the actual number given to a particular diameter magnet wire before any insulation in put on.
** Magnet Wire Diameter: is the numeral dimension as measured with a dial or digital micrometer.
*** Maximum Tension: The maximum tension measured using a specific measuring device in pounds or grams. Also the area that the magnet wire is stretched or a change in specific wire diameter and D.C. resistance.
****The number of turns wound side by side that will fit in a bobbin with a 1 traverse or winding area.
Magnet Wire Magnet Wire Maximum Tension Turns per inch
|(AWG)*||Diameter **||(lb & grams)***||(single build)****|
|30 awg||.0109||1.6 lb||91.7 turns|
|31 awg||.0097||1.3 lb||103.0|
|32 awg||.0088||1.0 lb||113.6|
|33 awg||.0078||360 grams||128.2|
|34 awg||.0070||280 grams||142.8|
|35 awg||.0062||220 grams||161.2|
|36 awg||.0056||180 grams||178.5|
|37 awg||.0050||140 grams||200.0|
|38 awg||.0045||110 grams||222.2|
|39 awg||.0039||87 grams||256.4|
|40 awg||.0035||69 grams||285.7|
|41 awg||.0031||56 grams||322.5|
|42 awg||.0028||45 grams||357.1|
|43 awg||.0025||35 grams||400.0|
|44 awg||.0022||29 grams||454.5|
|45 awg||.00195||18.2 grams||512.8|
|46 awg||.00175||14.5 grams||571.4|
|47 awg||.00160||11.5 grams||625.0|
|48 awg||.00140||9.05 grams||714.2|
86. I am interested in looking up patents of popular guitars and pickups, what are some of the more popular patent numbers? What are patents for? Bruce Botts-Cincinnati, Ohio
A patent is a government grant that allows the inventor to make, use and sell for a certain amount of time. It gives the inventor exclusive right to an invention or discovery. To be eligible for a patent, an invention must be new, useful or improvement of an existing patent. All patents other than design patents give the inventor control over an invention for 17 years. He must pay and protect his own invention which can be quite costly. Design patents are issued for 3 1/2, 7 or 14 years at the inventors option. A patent cannot be renewed except by a special act of Congress. It takes an average of two years for the U.S. Patent and Trademark Office to issue a patent. Manufactures put a Patent Applied For as soon as a patent is applied for to get the newly invented product on the market. The patented article may be marked with either a patent number or just be marked Patented. If an invention is copied without the owners permission, it is called infringement and the owner may sue for damages. Trademarks and Patents must be issued for each country where you need to be protected.
87. Is there such a thing as half gauges (AWG) of magnet wire used for making pickups? Lewis Harley - Isle of Skye, Scotland
Yes there is and I often find that this is very useful when trying to wind a coil to a specific number of turns and getting the right D.C. resistance. The chart below will show you the most popular wire gauges and the differences between the whole and half gauges. The half gauge wire is more expensive and I try to get samples to experiment with.
Magnet Wire Ohms per 1,000 feet
|(AWG)||Nominal Ohms @ 20? C|
88. How can you make a single coil have a stereo sound coming out of two amplifiers? Jim Sharp - Webster, Mass.
There are a few things you can do if your winding or making a pickup from scratch. Wind a single coil (like a Stratocaster bobbin) using two different gauges of magnet wire and wind them both together. Try using a 43 and 44 gauge magnet wire. You would need to put an extra eyelet in the bobbin or run an extra wire out from the coil when finished. Start both the 43 and 44 gauge magnet wires in your beginning eyelet. Try hand winding and guiding both wires at the same time and fill the coil to the maximum amount. Carefully wind without making the coil overwound or too fat. You need to put your cover back on. Take one of the two wires and connect it to another eyelet. If you put in an extra eyelet, connect the 3rd coil wire to it. Connect the magnet wire to the third eyelet or lead wire. Solder the eyelets and your pickup will have three leads coming out. The beginning two wires in the eyelet should be connected to ground and the other two wires can be connected to their separate volume control thats connected to one side of the stereo jack. Using a stereo guitar cable plugged into separate amplifiers. You will get different frequencies out of each amp. Its great for recording and you can switch between the coils use both.
- Single Coil Bobbin with extra eyelet or terminals for connecting magnet wires.
- 43 & 44 gauge of magnet wire. I use 43 & 44 gauge magnet wire as the larger gauge makes the coils too fat and you cant wind enough turns for increased output.
- Solder lead wires to the three eyelets. The beginning eyelet connected to ground. the 2nd & 3rd eyelets are connected to the right & left side of the jack or separate volumes if you wish first.
- You can design custom circuits & switching for this kind of pickup.
You can use a tapped pickup and run each side of the tapped coil to separate amps or channels. The pickup is not true stereo with the strings going left / right but the different frequencies offers you an interesting sound. I did this for Adrian Belew years ago when we both lived in the Cincinnati, Ohio area. Adrians Gibson Firebird had three pickups and I wired it so each pickup could go out the right, left or both channels.
89. Many players remove pickup covers from their pickups. I own a Les Paul with Mini Humbuckers, can I remove the covers from them? Craig Gutshall, Santa Barbara, California
During the summer of 1967 I was hanging out at night club in New York City called the Steve Paul Scene. There I was watching a guitarist by the name of Glen Schwartz who was playing with his group The James Gang before Joe Walsh Joined the band. Glen later joined the group Pacific Gas & Electric. Glen was playing an Epiphone Riviera or Sheraton guitar with Epiphone mini humbuckers (each pickup had a row of 6 adjustable pole pieces) without covers. I looked at it closely and it looked like he used tape and glued the bobbins to the bottom plate. The bobbins, magnet and all the goodies inside the pickup are held in place by the cover. If you remove the cover everything will eventually get loose and dangle from the bottom plate. Mini humbuckers that have adjustable pole pieces stay more secure to the bottom plate than a Gibson Firebird pickup. The Firebird doesnt have adjustable poles for the bobbin to wrap around. The traditional Gibson (Patent Applied For) Humbuckers designed by Seth Lover have 4 wood screws through the bottom plate that firmly secure the two bobbins (adjustable and non-adjustable) to the Nickel-Silver bottom plate. The pole pieces used on the Epiphone pickups and Gibson Mini Humbuckers are headless-slotted 3/48 machine screws. The bottom plate on the Epiphone is also threaded to secure the adjustable pole piece screws and allow height adjustment up or down. The pole piece screws are firmly held by friction on the inner walls of the nylon bobbin. There are no mounting screws to hold the bobbins secure and extreme care should be done if removing the covers. The solder joints on the cover can snag the tape wrapped around the bobbin and break the fine gauge of magnet wire. Also removing the covers, your guitar strings may get caught under the edge of the bobbin and can damage or break the windings in the coil. The material thickness of the nylon bobbin is much less than a standard Humbucker could get damaged or worn by excessive playing. The pickup height adjustment is accomplished by using (2) 1 1/4 (length) X 3/48 (#3 screw and 48 threads per inch) round head slotted, machine screw. The pickups are mounted in a bezel (mounting ring) that supports the pickup in the instrument.
90. I have an old guitar with stock pickups that works but they sound bad to me, should the pickups be rewound to sound better? Clair Adelaide- London, England.
I never want to rewind an original pickup if it works and though it may sound bad to you, It may sound great to another player or collector. Many older pickups are very valuable and many have been broken or fail due to natural causes. If at all possible I would suggest having a new pickup made for the sound you want. If the pickup needs fabricating, there are several excellent pickup manufactures that could do the job for you. Collectors and players like myself always try to discourage any modification on older pickups, and if broken should be restored to stock specifications using the same technique and manufacturing procedures. When I get older pickups that have been broken or rewound, I carefully inspect the pickup, evaluate and make notes on the procedures I will be doing. When rebuilding the new pickup I use the existing or modified custom parts. I want the pickup to look like its never been worked on, and this keeps an original pickup from being destroyed until one day you may need it for resale or back to basics.
91. How many feet are in one pound of magnet wire? Cody Duncan- Santa Barbara, California.
For a nominal gauge of 42 AWG of magnet wire, one pound has 50,940 feet.
For a nominal gauge of 43 AWG of magnet wire, one pound had 66,140 feet.
50,940 feet = 9.64 miles or 16,980 yards. If a pickup has 7,500 ohms using nominal 42 AWG at 20?, (1,000 feet = 1,659 ohms) you will be using approx. 4,520 feet of magnet wire in the pickup. To get this I use: 7,500 ohms ? 1,659 = 4,520 feet of magnet wire around a pickup. If a pickup has 9,200 turns ? 54,240 inches (4,520 feet x 12 = 54,240) = 5.89 per average turn. The inner turns will be shorter than the outer turns. Have fun with this one........
92. Can you put a Patent Applied For decal on a product that already had a patent number granted to it? Kim McQueen, Florida
Talking to the patent office in Washington, DC they state that once a patent has been applied for, you may use the Patent Applied For decal or sticker during the term till the patent is granted. Once you have manufactured your product during the time allotted in the term of the patent, you can not re-use Patent Applied For on your product. You are not re-applying for a patent to a product that has already been granted a patent number.
93. Where can I get an inexpensive hand winder and do you need different types of tooling fixtures to wind various pickups? Nick Toth-Bloomington, Indiana
I have found very effective hand winders at Sewing Machine repair stores. They have motors and foot controls to adjust the speed while winding. The motors have to be firmly mounted for winding. The tension and winding angle need to be stable and free of any uncontrollable movement. The shaft on the motor has to be modified to hold the bobbin or coil form. In the early days Fender used a threaded screw on the winding fixture to hold the bobbin while winding. Look at the bottom of old Fender vulcanized fibre bobbins and you will see the hole between the D & G poles are threaded (6/32). When winding many types of pickups you need to make custom tooling for each bobbin shape. Some bobbins like humbuckers should be wound with an automatic winder because you need to match the two coils perfectly with equal turns per layer. You need to examine the shape of each bobbin and figure the best way to mount the pickup. Winding speed should be watched with extreme care as the bobbin could fly off the fixture and hit you. Always wear protective eye glasses too. Never use double faced tape to hold the bobbins on alone. The weight of the bobbin and if off centered bobbin can go flying through the air as the coil is wound fuller.
94. Can you put other pickups in a Fender Jazzmaster guitar? Howard Duncan- Bridgeport, New Jersey
The pickups can be made with a staggered pole piece pattern similar to a Fender Stratocaster. The arrangement of the pole piece give the pickup a string balance but also is important to the tonal character of the pickup. By lowering or raising certain poles the pickup will have its own inner phasing due to the various lengths of the magnets. Jazzmasters normally have slightly raised magnets that are flush with the top of the pickup cover. Strats have raised poles above the cover and earlier Jaguars have slightly raised poles like the Jazzmasters that later were staggered above the cover. Jazzmasters have the smoothest and warmest sound of all Fender guitars and was one of the nicest guitars built at the time. The biggest problem were the bridge rollers that would vibrate and move around too much especially if your using a lighter gauge of strings. The height adjust screws would unscrew and youd end up using wax or slide a shim under the threaded bridge roller to keep it from lowering. The best bridge I found that worked great for the Jazzmaster was a Fender Mustang Guitar bridge. They had solid steel rollers that needed no adjustment and gave a littler thicker sound. The unique tremolo had to be adjusted depending on the gauge of strings you were using. With a little modification and adjustment these are great sounding instruments.
95. The studs in my humbucker are loose and fall out. What can I do to help keep them in? Dave Hamilton-Seattle, Washington
I would use a small amount of Silicone thinly wiped around the stud and inserted back into the bobbin. Never use a permanent glue as you may want to have the pickups repaired and the glues could alter the shape of the bobbin. A thin layer of wax could coat the stud and insert it back into the bobbin. This can happen when molding the bobbin and certain plastics have different shrink tolerances. Also the plating on the stud could be too thin, leaving the part under spec. Consult the manufacturer too so he can solve problem.
96. What are some other magnets that could be used for guitar and bass pickups? Scott Neubert-Nashville, Tenn.
There are various magnets on the market that could be used but there are some factors I feel make them undesirable for commercial pickups. The price on many of the advanced magnet materials is sky high and some of their magnetic properties make the pickup sound undesirable for my ears. Examples:
Samarium Cobalt: a permanent magnet material that is widely used first generation high energy material. Its a rare earth element and exhibits extraordinary magnetic performance characteristics in energy product. They say that the expense can be offset by lowering component fabrication and material costs. Two grades I have experimented are Samarium Cobalt type 18 and type 22 HE. Type 18 is easier to magnetize and is used when multi-pole magnetization is required. Cobalt 22 HE exhibits higher energy product, greater temperature stability and increased corrosion resistance.
Neodymium-Iron -Boron 27: Is a later developed high energy magnet. It is manufactured of Non Critical Raw Materials and is most cost effective high energy magnet. Neodymium is a sintered material offering superior mechanical properties with less chip and cracking than Samarium Cobalt.
Cast Alnico 8 HE: The cast Alnico 8 HE is a straight line anisotropic (oriented) material which offers superior magnetic performance. The improved crystal structure and alloying technique allow Cast Alnico 8 HE to achieve a maximum energy product of 6 million gauss oersteds. Its coercive force is 2.5 times greater than Cast Alnico 5 which is pretty standard in the music industry. The Cast Alnico 8 HE have a greater resistance to demagnetization or calibration.
Sintered Alnico 8 H: This Alnico material is also a straight line anisotropic material which shares the same superior magnetic performance of the Cast Alnico 8 HE. The fine grain structure results in a magnet with more uniform flux distribution and stronger mechanical properties. The sintered Alnico 8 H has a lower magnetic energy than its cast counterpart. It can be manufactured to closer tolerances which prove to be more economical.
Ceramic 8: This is considered the premium grade of ceramic material. The Strontium Base material exhibits excellent peak energy and greater resistance to demagnetization than the Ceramic 5 counterpart.
97. Can you tell me about the insulation tape used on Gibson Patent Applied For Humbuckers? Jim O Mahoney-Santa Barbara, California
As of this publication Scotch Brand Electrical Tapes by 3M have discontinued manufacturing the #4 Flatback insulation tape. Gibson has been using the #4 Flatback Scotch insulation tape on just about every pickup model made from early pickup production to present. This has been my favorite tape because of its mechanical properties and use in production. The earlier #4 Flatback tape had a slight Olive color tint to it and can be seen on the early P-90s and Patent Applied For Humbuckers. The tape made later in production by Scotch is basically black. Here are some other Scotch Electrial Tapes.
#2 tape is a Black Crepe paper tape
#3 is a Natural color Flatback paper tape
#4 is the Black Flatback paper tape
#9 is a Resin/Fibre Crepe paper tape
#38 is an Ivory/Natural color Crepe
After the pickup is wound the finish wire is soldered to the magnet wire, the insulation tape is folded over the solder joint to keep the joint from cutting into the insulation on the magnet wire. If the insulation is broken, the magnet wire could oxidize and break in time. The coil is then wrapped with a layer of .250 tape and the lead wires are neatly taped into position extending towards the recessed square at the end of the bobbin. The beginning wire is also soldered to the hookup wire that extends through the square opening on the underside of the bobbin. The insulation tape is also folded around the solder joint in the beginning wire to help reduce oxidation or insulation breakdown in the magnet wire.
All of the paper tapes have a Rubber Resin-Thermosetting Adhesive. The standard lengths of the tape rolls are 36, 60 and 72 yards. The width of the tape can be cut to any desired width to be determined by the pickup manufacturer.
The #3 & #4 Flatback tapes can be slit to width with a tolerance of +/- .005
98. What are the basic pole piece spacing for Gibson and Fender Pickups? Robert Birkeland-Bergen, Norway
There are many models of pickups made and Ill be doing a much more detailed chart in later issues and the basic ones are listed in the chart below. Here is an easy way you can measure the distance between poles and string spacing. Use a good pair of calipers (dial calipers work best for me) and measure (center to center) the 1st pole to the 6th pole for guitars with 6 strings and 1st to 4th pole for a 4 string bass. If you have an instrument with more strings you can follow the example below.
7 poles-measure 1st to 7th (center to center) and (divide by 6) = pole to pole
6 poles-measure 1st to 6th (center to center) and (divide by 5) = pole to pole
5 poles-measure 1st to 5th (center to center) and (divide by 4) = pole to pole
4 poles-measure 1st to 4th (center to center) and (divide by 3) = pole to pole
99. Can I change the magnet in my humbucker with one from another pickup? Chill Boy- Cardiff, California
There are several magnets than can be used and here are a few things to consider:
In a standard Gibson type humbucker the typical magnet used measures .125 thick, .50 wide and 2.125 to 2.5 in length. The metal spacer under the adjustable bobbin is also .125 thick. You can find magnets with the same dimensions as the standard humbucker but with different magnetic strength. There are Alnico II, Alnico V, Alnico VII and Ceramics magnets in different grades. Depending on the gauge of wire, number of turns in combination with the stronger or weaker magnet, the tone of pickup will sound brighter with a stronger magnet or softer sounding with a weaker magnet. Consider the physical dimensions when trying to use another magnet too. If the magnet is thicker you will have to use longer bobbin mounting screws. They are the (4) round head, phillip or slotted screws that firmly hold the bobbin to the bottom plate. If the magnet is too thick the (4) screws can become loose and make the hardware in the pickup vibrate and become microphonic. The (4) screws should firmly hold the bobbins, magnet, and steel spacer in place. As mentioned in earlier articles, if the magnet is reversed magnetically when installed back into the pickup, there can be a chance the pickup will be out of phase when used with another pickup. The (4) round head, brass, wood screws are a #2 X .5 and work well when using a .125 thick magnet. If you use a thicker magnet, you need to use a longer #2 round head-wood screw.
100. I havent played my guitar in years and when I opened my case the pickups are all rusted and the lever switch is intermittent. L.T.- Boston, Mass.
The first thing I thought about when I read your letter was the occasional high humidity where you live. I grew up in southern New Jersey and remember when my guitar would be covered in moisture when opening my case. Leaving your guitar case open when you rehearse allows the lining of the case to absorb moisture. On hot days your case can actually sweat and the high moisture content can make your pickup rust and the contacts on the lever switch to oxidize. Try finding a (Desiccant pack) which is used for humidity control and protection of materials subject to corrosion or rust caused by high humidity. The container contains granules that absorb moisture. The packet can be put within the instrument case to absorb moisture and can be easily regenerated by placing the unit in an oven for a few hours at low temperature to dry it out. 10 pounds of granules can hold about 12 pounds of water vapor. I will look for a source that sells Desiccant packs. I have often put my open case in a closet with a de-humidifier. I purchased a small one from Sears that works quite well. I was amazed how much moisture came out of the case lining.