126. Back in the 60's I ordered PU-490 humbucker for one of my Gibson guitars. What are the model numbers for other Gibson pickups? Kenny Poole, Cincinnati, Ohio
Looking back in my records I came across some numbers of other Gibson pickups that will be helpful for your records. Below I will give you the Symbol Key and Pickup Model from pickup charts I have from the mid 60's.
Symbol Key
CPA-B PICKUP-FRONT ONLY (INCLUDES COVERS, MOUNTING RING, ETC.) -PU
CPA-C PICKUP-BACK ONLY-PU
CPA-N COIL (PICKUP) ONLY-FRONT PU-C
CPA-O COIL (PICKUP) ONLY-BACK-PU-C
CPA-T PICKUP-CENTER (3RD)-ONLY
GIBSON GUITARS PICKUP MODEL
S400CES, CESN: L5CES, CESN
CPA-5-B FRONT PICKUP ONLY PU492-2G
CPA-5-C BACK PICKUP ONLY PU490-4G
CPA-5-N COIL (PICKUP) ONLY-FRONT PUC-492G
CPA-5-O COIL (PICKUP) ONLY-BACK PUC-490G
BYRDLAND, ES350TD
CPA-15-B FRONT PICKUP ONLY PU492-2G
CPA-15-C BACK PICKUP ONLY PU492-1G
CPA-15-N COIL (PICKUP) ONLY-F & B PUC-492G
JOHNNY SMITH DOUBLE
CPA-122-B FRONT PICKUP PU-122-2G
CPA-122-C BACK PICKUP PU-122-1G
CPA-122-N COIL ONLY-F & B PUC-495
JOHNNY SMITH
CPA-120-B PICKUP ONLY PU-120-G
CPA-120-N COIL ONLY (NO COVER) PUC-495
SWITCHMASTER, (ES5)
CPA-20-B FRONT PICKUP ONLY PU-492-2G
CPA-20-C BACK PICKUP ONLY PU-490-4G
CPA-20-T CENTER PICKUP ONLY PU-490-1G
CPA-20-N COIL-ONLY FRONT PUC-492G
CPA-20-O COIL-BACK & CENTER PUC-490G
TAL FARLOW
CPA-22-B FRONT PICKUP ONLY PU-22N
CPA-22-C BACK PICKUP ONLY PU-490-1N
CPA-22N COIL (PICKUP) F & B PUC-490N
BARNEY KESSEL CUSTOM
CPA-25-B FRONT PICKUP ONLY PU-492-2G
CPA-25-C BACK PICKUP ONLY PU-492-4G
CPA-25-N COIL (PICKUP) FRONT PUC-492G
CPA-25-O COIL (PICKUP) BACK PUC-490G
BARNEY KESSEL regular
CPA-30-B FRONT PICKUP ONLY PU-492-2N
CPA-30-C BACK PICKUP ONLY PU-490-1N
CPA-30-N COIL (PICKUP) FRONT PUC-492N
CPA-30-O COIL (PICKUP) BACK PUC-490N
TRINI LOPEZ CUSTOM
CPA-32-B FRONT PICKUP ONLY PU-492-2N
CPA-32-C BACK PICKUP ONLY PU-490-1N
CPA-32-N COIL (PICKUP) FRONT PUC-492N
CPA-32-O COIL (PICKUP) BACK PUC-490N
TRINI LOPEZ Regular (see ES335TD)
ES-125, 125C, 125T, 125TC, 225T, & 330T, TC
CPA-60-B PICKUP (DOG EAR) PU-60N
CPA-60-N COIL (less cover ,base, magnet) PUC-476
ES-125CD, 125TD, 125TCD, 225TD
CPA-50-B FRONT PICKUP ONLY PU-60N
CPA-50-C BACK PICKUP ONLY PU-95N
CPA-50N COIL (PICKUP) F & B PUC-476
ES-175D, ES-175DN
CPA-35-B FRONT PICKUP ONLY PU-490-2N
CPA-35-C BACK PICKUP ONLY PU-490-1N
CPA-35-N COIL (PICKUP) F & B PUC-490N
ES-175, ES-175N
CPA-40-B PICKUP ONLY PU-490N
CPA-40-N COIL (PICKUP) ONLY PUC-490N
ES-140T, ES-125T 3/4
CPA-75-B PICKUP ONLY PU-95N
CPA-75-N COIL (less cover, base, magnets) PUC-476
ES-120T
CPA-68-B PICKUP w/COVER PU-380
CPA-68-N COIL ONLY PUC-380
ES-330T, ES-330TD see ES-125 ( CPA60)
ES-330TD, ES-330TDC
CPA-332-B FRONT PICKUP ONLY PU-60N
CPA-332-C BACK PICKUP ONLY PU-95N
CPA-332-N COIL ONLY (F & B) PUC-476
ES-335TD, TDC; TRINI LOPEZ regular
CPA-335-B FRONT PICKUP ONLY PU-335-2N
CPA-335-C BACK PICKUP ONLY PU-335-1N
CPA-335-N COIL ONLY (F & B) PUC-335N
ES-345TD; ES-355TD-SV (stereo-varitone)
CPA-345-B FRONT PICKUP ONLY PU-345-2G
CPA-345-C BACK PICKUP ONLY PU-345-1G
CPA-345-N COIL ONLY (F & B) PUC-345G
ES-355TD
CPA-355-B FRONT PICKUP ONLY PU-355-2G
CPA-355-C BACK PICKUP ONLY PU-355-1G
CPA-355-N COIL ONLY (F & B) PUC-355G
FIREBIRD VII
CPA-740-B FRONT PICKUP ONLY PU-740-2G
CPA-740-C BACK PICKUP ONLY PU-740-1G
CPA-740-T CENTER PICKUP ONLY PU-740-3G
FIREBIRD V & III
CPA-720-B FRONT PICKUP ONLY PU-720-2N
CPA-720-C BACK PICKUP ONLY PU-720-1N
CPA-720-N COIL ONLY (F & B) PUC-720
FIREBIRD I
CPA-730-B FRONT & BACK PICKUP PU-90N
CPA-730-N COIL ONLY (F & B) PUC-476
SG CUSTOM
CPA-80-B FRONT PICKUP ONLY PU-490-2G
CPA-80-C BACK PICKUP ONLY PU-490-1G
CPA-80-T CENTER PICKUP ONLY PU-490-3G
CPA-80-N COIL ONLY (F-B & M) PU-490G
SG REGULAR
CPA-85-B FRONT PICKUP ONLY PU-490-2N
CPA-85-C BACK PICKUP ONLY PU-490-1N
CPA-85-N COIL ONLY PUC-490G
SG SPECIAL
CPA-90-B PICKUP ONLY (F & B) PU-90N
CPA-90-N COIL (less cover, base, magnets) PUC-476
SG Jr.; SG-TV
CPA-95-B PICKUP ONLY w/COVER PU-95N
CPA-95-N COIL (less cover, base, magnets) PUC-476
MELODY MAKER DOUBLE (MM-D)
CPA-375-B PICKUP ONLY PU-380
CPA-375-N COIL ONLY PUC-380
MELODY MAKER regular (MM); 3/4
CPA-380-B PICKUP w/COVER PU-380
CPA-380-N COIL ONLY PUC-380
FLAT-TOP ELECTRIC GUITAR
J-160 E
CPA-365-B PICKUP ONLY w/COVER PU-365N
CPA-365-N COIL ONLY PUC-476
C-1 E
CPA-280 CERAMIC PICKUP PU-280
ELECTRIC BASS
THUNDERBIRD IV
CPA-760-B FRONT PICKUP ONLY PU-760-2N
CPA-760-C BACK PICKUP ONLY PU-760-1N
CPA-760-N COIL ONLY PUC-760
THUNDERBIRD II
CPA-750-B PICKUP ONLY PU-760-1N
EB-OF
CPA-665-B PICKUP ONLY PU-601N
CPA-665-N COIL ONLY PUC-601
EB-O
CPA-657-B FRONT PICKUP ONLY PU-601-CR
CPA-657-C BACK PICKUP ONLY PU-657
CPA-657-N FRONT COIL ONLY PU-601
CPA-657-O BACK COIL ONLY PUC-495
CPA-657-P CHOKE GA-90C-1
EB-6
CPA-652-B FRONT PICKUP ONLY PU-652-2N
CPA-652-C BACK PICKUP ONLY PU-652-1N
CPA-652-N COIL (PICKUP) ONLY PUC-490N
EB-2
CPA-655-B PICKUP ONLY PU-601N
CPA-655-N COIL ONLY PU-601
CPA-655-P CHOKE GA-90C-1
NOTE: The old-style EB-1 (Violin shape) cannot use the above pickups
ETG-150
CPA-65-B PICKUP ONLY PU-65N or PU-420n
CPA-65-N COIL ONLY PUC-476
ELECTRIC MANDOLIN
FLORENTINE
CPA-415-B PICKUP ONLY PU-415G
CPA-415-N COIL ONLY PUC-415
EM-150
CPA-420-B PICKUP ONLY PU-420
CPA-420-N COIL ONLY PUC-420
EH-150 6 String PU-150-6
EH-150 8 String PU-150-8
OSCAR MOORE
STRAIGHT BAR P.U. PU-150
MISC. PICKUPS Position Part #
Low Impedance pickup front for LP Bass 13555
Low Impedance pickup back for LP Bass 13560
SG Professional front & back 13216
Melody Maker PUC-380 70376
Dog Ear P-90 old SG, jr., spec. 13550
ES-330-125 front 13500
J160 E P-90 13511
ES-330 back 13502
SG-100-200-250 Melody maker type 13570
Pickup 280 Electric Classic 13529
Humbucker-front Flying V-SG Stand. 13219
Humbucker-back Flying V-SG Stand. 13220
Les Paul Recording back & front 13557
SG Custom front pickup 13513
SG Custom center pickup 13514
SG Custom back pickup 13512
Johnny Smith front pickup 13504
Johnny Smith back pickup 13503
Crest front pickup 13551
Crest back pickup 13552
EB Bass pickups neck position 13517
Les Paul Deluxe front pickup 13544
Les Paul Deluxe back pickup 13545

127. Can magnets used in pickups be plated? Don Hacker, Atlanta, Georgia
From my notes given to me by Indiana General years ago they say that several types of protective coating and coverings are available for many magnets. Due to the porosity and high resistivity, Ceramic magnets cannot be electroplated. Most Alnico magnets can be plated to prevent corrosion and a covering suitable for soldering. Cast alnico magnets can be electroplated with cadmium, copper, nickel, zinc, tin, and gold plating. Many of the “Alnico” P-90 shaped pickups with rectangular alnico 5 pole pieces are gold and nickel plated according to designer Seth E. Lover. The plating helped when soldering the elevator legs onto the bar magnet for pole height adjustment. When the alnico magnets are cast it’s harder to plate due to poor adherence and imperfections that occur. The porosity of sintered alnico magnets makes it difficult to plate successfully. If the magnets are impregnated with a suitable material or light machining, better plating will result. Many magnets are often painted with silver paint, especially permanent magnets in analog meters. Flux output is usually unaffected by insulations.

128. What is the average flux loss in newly magnetized permanent magnets? Jamie Shane, Santa Barbara, CA
The magnetic domains are locked in position as established by initial magnetization. The domains are held in place until acted upon by forces exceeding the locked in force. Various factors affecting magnet stability include metallurgical changes, time, temperature, reluctance changes, adverse fields, shock, stress and vibration as quoted from Indiana General.
Metallurgical: In the older magnets such as cobalt, tungsten or chromium-steels, metallurgical changes may take place at or near room temperature as a function of time. It is important to note that metallurgical changes do not take place in any measurable degree at room temperature in the newer permanent magnets such as Alnico or Ceramic. IG
Time: Time versus flux records made by precise lab measurements, under carefully controlled conditions have shown that a newly magnetized magnet will lose a minor percent of its flux as a function of “age”. IG
Temperature: 1. Metallurgical changes occur in magnets exposed to very high temperatures. Such flux changes are not recoverable by remagnetization.
2. Irreversible losses: are defined as partial demagnetization of the magnet from exposure to high or low temperatures. These losses are recoverable by remagnetization. 3. Reversible changes are positive or negative flux changes which are recovered when the magnet returns to the initial temperature. IG
Reluctance: changes many occur if a magnet is magnetized in a circuit and subsequently subjected to permeance changes (such as a air gap or opening in a circuit of a magnet). IG
Others: Contacting the magnet with ferro-magnetic materials such as screw drivers or other metal objects at points other than the poles can drop the flux at the poles. Keep other magnetic objects away from magnets. Shipping magnets in close proximity to each other can change the flux in a magnet. Proper equipment must be used to properly magnetize the magnet to its maximum strength. The magnets should be shipped in a proper North - South relationship. IG
Adverse Fields: Adverse fields may partially demagnetize a magnet, depending upon the material properties and the intensity and direction of the field. IG
Shock: Shock, stress and vibration on most permanent magnet materials are very minor. Dropping a magnet on a metal surface can reduce the flux in the magnet.
Flux loss In newly Magnetized Permanent Magnets.
Magnet Material Loss per Loss at 100,00 hrs
log cycle (11.4 yrs.)
Essentially Essentially
Ceramic Zero Zero
Alnico 3 (near max. energy) .4 % 2.4 %
Alnico 3 (near coercive) .6 % 3.6 %
Alnico 5 (near residual) .01 % .06 %
Alnico 5 (near max. energy) .15 % .9%
Alnico 5 (near coercive) .4 % 2.4 %
When your pickups need to be worked on, please have a reliable repairman work on them. Every day, unique and valuable pickups are rewound that don’t need to be. , If your pickups don’t sound right for you, replace them with something you do like instead of modifying or having the originals rewound. There are several pickup manufactures that can help you find the sound you’re looking for. Remember, the pickups you are modifying will be “Vintage” someday! SWD

129. I have a Sho-Bud Double Neck Pedal Steel. Can the magnets be re-magnetized if they loose their sensitivity over the years? Alvin Sydnor, Boothwyn, Pennsylvania
Magnets can be re-magnetized when the magnet is demagnetized by several factors. When magnetizing pickups, a few methods can be used. One method is using a semi-continuous DC magnetizer that uses iron core electromagnets that are energized by filtered direct current. They have adjustable and interchangeable pole pieces to fit most rod and bar magnets used in musical instrument pickups. I’ve used powerful horseshoe magnets to magnetize bar and rod magnets. Some manufacturers magnetize the rod or bar magnet one at a time before the bobbin or flatwork is fabricated and others magnetize the magnet(s) after the pickup is completely assembled. There are also capacitor-discharge magnetizers, half cycle, DC-bias/AC-inrush type and other special purpose types. How should the pickup string height be adjusted? AS. I tilt the pickup and listen to the fullness of the output as the strings are plucked. I don’t use a pick, so I lower the bass side of the pickup so it’s not too fat sounding. When I play a chord, I can hit several strings simultaneously and listen closely to the overall balance of each string. If the bottom is too thick, I lower the bass side of the pickup. If it’s not full enough, I raise it. Normally I adjust pedal and lap steel pickups approx. 1/16”-1/8” on the treble side and 1/8”-3/16” on the bass side on the pickup nearest the bridge.

130. I’m the proud owner of a November 1950 Broadcaster. The treble pickup is loud and doesn’t feed back, however the neck pickup does. Would it be advisable to have the neck pickup repotted? Nick Carras, Myersville, Maryland
Broadcaster and Telecaster rhythm pickups are not wax potted, but were treated with a potting solution to protect the coil from damage and give mechanical stability. After the coil and bobbins are potted and let dry, the cover is then put in place and the 3 tabs on the cover are mechanically bent over the edges of the Fibre board to hold it in place. Early amplifiers had low output and feedback was not as prevalent until the higher powered amps and performing in close proximity to the speaker caused the pickups to start howling. I never like seeing an old original pickup modified or changed in any way. Potting the pickup will lower the value even though it may improve the performance of the instrument. If your wiring has been modified or the pickups have been soldered in and out, I would try to find a vintage replacement that has been specially made for your desired sound and output and one that’s properly potted to eliminate unwanted feedback. When using the original pickups I would try moving further away from the amp or turn down and let the monitors or sound system do the work.

131. For many years I’ve been using Seymour Duncan pickups and on the bottom of the Humbuckers and Singles coils I see a label stamped “DD-J”. What do the letters stand for? Mark “Farquar” Vaccacio- “Beatlemania”, New York.
On the bottom of my pickups I use a code or abbreviation on pickup models for identification as many models can physically look alike and when removed from the box or when it’s in an instrument will help identify it. Many of the pickups have several numbers or letters. For example: DD-J is a Duncan Distortion built by Maricella Juarez made after 1983. Maricella currently works with me in the “Antiquity” room. Some of the most common pickup codes shown in (fig.1) on the bottom of pickups are:

(fig.1) Code Pickup Model(s) Code Pickup Model(s) 59N 59 Model Humbucker-Neck 1 Strat-Vintage Staggered 59B 59 Model Humbucker-Bridge 1L Strat-Vintage Staggered-Left JMN Jazz Model Humbucker-Neck 2 Strat-Vintage Flat JMB Jazz Model Humbucker-Bridge 3 Strat-Hot MG Stag Mag Humbucker 3T Strat-Hot-Tapped JB JB Model Humbucker 4 Strat-Quarter Pound DC Duncan Custom Humbucker 4T Strat-Quarter Pound-Tapped SEY Seymourizer II Humbucker 5 Strat-Custom Staggered DD Duncan Distortion 5L Strat-Custom Staggered-Left N Invader Humbucker-Neck 5T Strat-Custom Staggered -Tapped B Invader Humbucker-Bridge 6 Strat-Custom Flat AH1B Allan Holdsworth Humbucker 7 Strat-Quarter Pound Staggered PGN Pearly Gates Humbucker-Neck 7T Strat-Quarter Pound Staggered-Tap PGB Pearly Gates Humbucker-Bridge 1B Tele Lead-Vintage Broadcaster N Full Shred Humbucker-Neck 1 Tele Lead-54' Vintage B Full Shred Humbucker-Bridge 1 Tele Rhythm CC Custom Custom Humbucker 2 Tele-Hot Lead 12 George Lynch Screamin' Demon 2T Tele-Hot Lead-Tapped 1N or 1B Mini-Humbuckers 2 Tele-Hot Rhythm 2N or 2B Mini-Humbuckers 3 Tele Lead-Quarter Pound 3N or 3B Mini-Humbuckers 3T Tele Lead-Quarter Pound 1N or 1B Vintage Mini Humbuckers 3 Tele Rhythm-Quarter Pound 2N or 2B Custom Mini Humbuckers 3T Tele Rhythm-Quarter Pound-tap 3N or 3B Seymourized Mini Humbuckers 1N or 1B Jaguar-Vintage-Neck or Bridge 1N or 1B Vintage Soapbars 2N or 2B Jaguar-Hot 2N or 2B Hot Soapbars 3N or 3B Jaguar-Quarter Pound 3N or 3B Custom Soapbars 1N or 1B Jazzmaster-Vintage 2N or 2B Jazzmaster-Hot

Pickups can use letters or numbers 3N or 3B Jazzmaster-Quarter Pound
After the letters or numbers are stamped on the sticker, there will be another letter used to identify a specific assembler. You will see the letters used by the final assembler in the Final Assembler chart below. Before the final inspection the pickups are made with the initial of the assembler who puts everything together. The final assembler works on specific models from Humbuckers, Single coils, Stacks and Rails. In the code column (fig. 2)below you will see two J’s but one assembles humbuckers and the other stacks. There may be other initials that I’ve forgotten but this will help most of you. I often get calls wanting to know other details about my various models so let me know what specific information you may need on particular pickups. Some abbreviations are:
HB-Humbuckers---This may take in a variety of Humbucking models including Mini’s.
SC-Single Coils---Mostly all single coils comprising of Vintage, Hot, Quarter Pound etc.
STK-Stack Pickups---Hand assembly of pickups with two coils, one on top of each other.
RAILS-Hot Rails etc.---Hand assembly of pickups with two coils side by side.

(fig.2) Code Final Assembler Model(s) A Raul Araiza Single Coils B Leticia Bautista Single Coils C Catalina Padilla Rails D Debbie Nyquist Humbuckers E Edward Madrigal Humbuckers G Gloria Ocompo Humbuckers J Maricella Juarez-83' on HB-SC-STK-RAILS J Janice Salazar-till 83' Stacks L Lidia Daniel Humbuckers L Leticia Quintero-87'-90' Stacks & Rails M Martha Cameron HB-SC O Oti Mora Stacks & Rails P Lupe Perez-86' on Rails P Patty Vasquez-till 86' Stacks & Rails R Connie Rocha Single Coils V Joe Velez Single Coils X Mai Xiong Stacks

132. Why do you like hand winding a pickup rather than having the coil machine automatically wind the coil. Ben Arnett, Raleigh, NC
I find that winding by hand allows me to control the shape of the coil, avoids snags on the edge of the bobbins and gives the coil a desired tension. I enjoy layering the magnet wire onto the bobbin to make winding an art like a fly fisherman casting his line. I like winding with a light directly over the pickup being wound. I keep focused on the coil and find it best to turn off all lights around me. It helps to keep the outside shadows off the coil so you can see the shape better when winding. I concentrate on the winding coil and listen to the sound as it turns. I listen to the tone of the spinning coil for the proper winding speed for proper tension on the wire. I let the wire flow between my thumb and index finger of my right or left hand depending what type of bobbin I’m winding. My winder has several pre-set speeds and my left foot controls how fast the mandrel spins. I can change the pulley and belt sizes for a variety of speeds to wind certain coils and bobbins. It’s portable and I like taking it to many vintage shows. I use slower speeds for winding paper or fabricated bobbins and medium speeds for Vulcanized Fibre bobbins and higher speeds for molded bobbins. If you wind paper bobbins to fast, the tension from the magnet wire wrapping tightly around the bobbin can cause the coil form to flair, distort and even separate. When I wind custom pickups or repair broken ones, I measure the DC resistance, DC resistance @ 1Khz, Inductance, Q, and Gauss of every custom pickup made. I keep written documentation on every pickup made for future reference in case the player needs an exact duplicate. It’s always good practice to keep records of your clients instruments and wiring schematics especially if your client is on the road and some other repairman works on it and needs the information faxed to them.

133. I have a single coil P-Bass and from years of resting my thumb on the lip of the bobbin, the top is starting to come off. What can I do? Bill Schwartz, Woodbury, New Jersey
I’ve seen this happen many times and it can be difficult trying to glue because of the wax potting solution on older pickups. Some reissue single coil P-Bass pickups are potted in solutions other than wax and I have carefully used a drop of Cyanoacrylate (Super Glue) carefully at the top of the pole piece using a glue pen. Hold the top down using a piece of wax paper as an insulator between your fingers and vulcanized fibre so you don’t end up walking around with a pickup stuck to your finger. Make sure you always wear safety glasses when soldering or using any chemicals especially Super Glue. Loctite Super Bonder 495 works well too. After lightly gluing the flatwork carefully clean or scrape off any residue off the magnets using a non metallic scraper so you don’t scratch the surface of the magnets. If the job is difficult then have one of the qualified pickup winders carefully do the job for you.

134. I want to rewind my Gretsch Filtertron pickup to get a real clear tone. What gauge wire should I use and how many turns? Albert Jones, New Orleans, LA
There are many combinations of wire and turns for winding pickups but for Gretsch Filtertrons I like using 3,000 turns of 42 Heavy Formvar and you’ll get a nice clear vintage tone. Wind the top of the coil Top Left and Top Coming (the top of the bobbin comes towards you). I never like winding humbucking pickups by hand as I like to have the same layering on both coils used on one pickup. It helps the pickup to be better hum rejecting. The heavy Formvar has a thicker insulation and tension must be watched carefully. If you wind too fast the coil can become spongy not leaving enough time for the magnet wire to fit snug within each turn. If you wind too slow and not enough tension the coil will again loose and the desired number of turns can’t be obtained. If the tension is too tight the magnet wire will become stretched increasing the DC resistance of the coil. Also stretching the magnet wire can crack the insulation leaving it exposed to the elements and in time could oxidize and break.

135. Do humbucking pickups sound different if the pickup covers are removed? And if removing covers is not a good idea, why do manufacturers (including you) make them without covers? Gerard Ventura-Nacogdoches, TX
Using deep drawn covers made of brass or aluminum and then plated with chrome, nickel or gold plating can reduce the brightness in the pickup and nickel silver is one of the best materials to be used. It is easy to draw (form in deep draw molds) and has less capacitance than brass or aluminum. In earlier VGM articles I mentioned that I removed the covers because Jeff Beck did. You could see the exposed the coils and was the reasons double cream and zebra, Gibson “Patent Applied For” humbuckers started to become collectable. I thought (along with many other guitarist) that if you had double cream humbuckers, you would sound like Jeff Beck. Someone forgot to tell us that we had to practice too! With the covers on, the pickups have maximum shielding and removing them will allow unwanted electrical interference to be picked up by the coils.

136. I own a 63’ Strat and the 1st through 5th string sound bright but the 6th (low E) sounds dull. What could cause this? James Przeborowski, Schererville, Indiana
There are several reasons I have come across throughout the years. One could be a bad low E string. The wrapping on the string could have come loose or not have physical properties to attract the magnetic field in the pickup. Another can be the magnet rod pole piece has lost it’s magnetic field or has become degaussed. The particular magnet could be bad and not cast the proper specifications of an Alnico magnet. The combination of aluminum, cobalt, nickel and other materials may have not been fully mixed when the material was in the molten stage of casting. In a few cases I have had magnets that wouldn’t stay magnetized after they where charged. This rarely happens but a few get through even though magnet suppliers have a high amount of quality control. The pickup will sound softer and less bright with a weaker magnet. Check to see if the string is resting properly in the nut and it’s at a lower angle from the nut to tuning key. Old and dirty strings will make it sound dull too.

137. I took the coil of magnet wire off my single coil pickup and one of the end magnet were cracked. What caused that to happen? T.K. Hawkins-Toronto, Canada
Winding with too much tension on the magnet wire can cause extreme side pressure on the magnets as they are wound. This can cause the magnet to crack. When the rod magnets are assembled into the flatwork to make a bobbin, the arbor or force used to press the magnets into the fixture could crack the magnet too. Another way to break magnets is when removing the coil that needs to be rewound. If a wide sharp edged blade is used to cut the coil off, the force of the blade cutting through the coil can cause the ends to be forced in and crack under the extreme pressure.br>

138. I’ve experimented with winding a few pickups by hand and want a darker looking wire for my coil. What can I do to make the coil look darker?
Here’s another little trick I’ve used that works pretty well. I use a new large black felt tip “Magic Marker” and while winding pass the lighter colored insulation magnet wire over the felt tip. I keep the marker above the magnet wire as the coil is winding. This actually does two things, which can be helpful. It will make the magnet wire darker and also while drying bonds to the previous turn. This helps with reducing microphonic feedback and makes the coil much firmer. I wear little disposable plastic gloves while holding the felt marker as it can make a mess unless you are very careful. I can guide the magnet wire between the felt tip and index finger as the coil is being wound. You can hold the marker over the wire just before it winds onto the coil and this is best done using automatic traverse controls that guides the magnet wire back and forth on the bobbin. This is called “winding pitch” or rate the wire travels back and forth along with winding speed. The pitch similar to the threads in a screw or distance between each turn. I’ve wound coils using lighter colored insulation’s when I couldn’t find Plain Enamel. I had to make the outer part of the coil darker using the same technique by coloring the outer exposed coil. By using the black “Sharpie” or felt marker help restore the coil to make the pickup look more original. Good luck with your experiments.

139. I have a 1954 Stringmaster Triple 8 Steel Guitar with two metal covered pickups in each neck. Each pickup reads 7.3 K ohms and seem identically wound and same polarity. The pickups hum even when both coils are used together. What can be done to make them quiet? Mark Durante-Chicago, Illinois
Later Stringmasters have one of the two pickups in each neck reverse wound and reverse polarity. This will make the pickups humbucking and quiet when both pickups are used together. The blend switch located behind the bridge saddle on each neck and can blend in the 2nd pickup when fully turned clockwise and only one pickup when fully turned counter-clockwise. This is a great setup and I often use this on conventional electric guitars as well. On your current setup the magnets would have to be reverse magnetized and the coil would have to be reverse wound or the wires reversed. If you reverse the wires when using a metal cover I would insulate the magnets so they don’t accidentally short out to the grounded cover. I would measure the existing gauss or strength of the magnetic field before the pickup is magnetized. If it is currently south polarity on top of the pickup I would remagnetize it north polarity. I would then recalibrate it to it’s previous gauss.

140. I heard that many of the Fender parts are case hardened. Why is this done? Bob Banse-San Diego, California
Case hardening is a term that is used to describe a process in which changes the composition of the surface layers of ferrous alloys a hardened surface layer can be produced to made the surface harder and used on many bridges such as Telecasters, Precision Bass, Jazz Bass and others such as neck and control plates. To get more technical carburizing is a form of case hardening which results in a hard surface layer being manufactured with ferrous alloys. You heat the alloy to the austenitic state in a carbon rich atmosphere so that carbon diffuses into the surface layers, then quenching to convert the surface layers to martensite. This information is from the Engineering Materials Pocket book, CRC Press. Many repairman have noticed when trying to add a switch to a Telecaster lever plate how hard it was to drill through. Fender neck plates are case hardened too. It keeps the materials strong and especially when height adjust screws are used, it helps prevents deep pits and surface dents from the pressure. Early lap steels had the bridge units case hardened to keep the bent steel firmer and to keep the strings from cutting into the bridge saddles.

141. Why when I measure the DC resistance of my pickup when it is cool and later when it is hotter does the resistance get higher? Ted Paxton-Tuson, Arizona
Magnet wire is insulated copper wire and the ohms per thousand feet is normally measured at 20? C or 68? Fahrenheit. 42 gauge magnet wire has 1,659 ohms per 1,000 feet of magnet wire at 20? or 68? F.
Note: 1,659 ohms is the same as 1.659 K ohms
1,000 feet of 42 AWG magnet = 1,659 ohms nominal at 20? C or 68 ? F.
If the temperature of the magnet wire is 25? C or 77? F, I multiply 1,659 (ohms per 1,000 feet) by 1.0197 (Factor) and get 1,692 DC ohms which is an increase of 33 ohms due to the increase in temperature.
Another way of doing it is: If your magnet wire measure 1,692 ohms per 1,000 feet at 77? F. you then divide by the conversion factor which is 1.0197, this will give you the nominal ohms at 68? F by which most magnet wire manufacturers use as a standard.
This may be confusing to most players using pickups but it is helpful in rewinding and manufacturing. I use this conversion all the time to determine exactly what gauge of magnet wire I am using or what’s used on a vintage pickup. The conversion chart below can be used with any magnet wire to determine what the actual gauge is at the nominal 68? F or 20? C.
Note: to measure 1,000 feet of magnet wire sounds difficult but I use a digital meter and measure 10’ (feet) and multiply the number by 100 to get ohms per 1,000 feet. Once I determine what that number is. I measure the room temperature and use the conversion chart. The number I end up with is the actual ohms per 1,000 feet at 20? C or 68? F.
If a pickup has 6.636 K ohms, the pickup has 4,000 feet of magnet wire.
Example: 1,000 feet of 42 gauge of magnet wire at 68? F equals 1,659 ohms X (multiply) 4 (= 4,000 feet of magnet wire) = 6,636 ohms or 6.636 K ohms.Conversion Chart for Magnet Wire:
?C Factor ?F ?C Factor ?F ?C Factor ?F
15 .9804 59.0 24 1.0157 75.2 33 1.0511 91.4
16 .9842 60.8 25 1.0197 77.0 34 1.0551 93.2
17 .9882 62.6 26 1.0235 78.8 35 1.0590 95.0
18 .9922 64.4 27 1.0275 80.6 36 1.0630 96.8
19 .9961 66.2 28 1.0315 82.4 37 1.0668 98.6
20 1.000 68.0 29 1.0354 84.2 38 1.0709 100.4
21 1.0039 69.8 30 1.0393 86.0 39 1.0747 102.2
22 1.0079 71.6 31 1.0433 87.8 40 1.0786 104.0
23 1.0118 73.4 32 1.0471 89.6

142. I want to put my name and ID number on the bar magnets in my pickups for identification. What should I use? Mike Johnson-Portland, Oregon
I have used two types of scribers that work well. One is made by General Tool Mfg. Co. in New York (most well stocked hardware stores carry General Tools) and is part # 88. The scriber has a Tungsten Carbide point that’s useful for scribing stainless steel, ceramics, glass and magnets. The scriber # 88 has a screw chuck for reversing the point when not in use and has a knurled aluminum pencil like shaft. Many times when I build a custom pickup I put my initials on the magnets for dating and future identification. There are also diamond tipped scribers but they cost much more. Using a monocle I can scribe my initials so small it’s hard to see with the naked eye.

143. How can I make my Precision Bass sound similar to a bridge pickup on a Rickenbacker Bass that has a brighter bottom end? Niles Harper- Costa Mesa, Californiabr> The easiest way to do it is to use a .0047 Mfd. capacitor in series with (in between) the hot output from the pickup and the input on the #3 lug on the volume control. Note: looking at the bottom view of the volume control the #1 lug is grounded to the pot, the #2 lug is the hot output to the jack and the #3 lug is normally the input from the pickup. This can also be done using a push pull tone pot to bypass the capacitor.

144. The height adjust thread on my humbucker bottom plate is stripped and the pickup will not stay adjusted to the height I need. What can I do? Bill Hudson, Los Angeles, California
There are a few things you can do to help keep you pickup adjusted properly. You can try asking the manufacturer for a replacement bottom plate. You may be able to purchase one from a music dealer that has a broken pickup or parts and maybe the bottom plate can be salvaged. The tapped hole is 3/48 (3 = the screw diameter and the 48 = threads per inch) on Gibson pickups and you can solder a 3/48 nut to the bottom of the leg for added threads to hold the height screw. The height adjust spring used in Gibson humbuckers have strong compression that help keep the pickup from rocking back and forth within the mounting ring or pickguard. Just putting solder around the stripped hole doesn’t have enough strength to hold the pickup to the proper height especially when using the compression springs. Again you can use a 3/48 nut and tighten it on the screw to the desired pickup height you need.

145. When I use two pickups together on my Strat, whey do they call it the out of phase position? What actually happens. Ken Larson, Colorado
Using a 5 way lever switch can combine the bridge and middle pickup in the # 2 position and combine the neck and middle pickup in the # 4 position. The # 1 position (bridge pickup alone), the # 3 position (middle pickup alone) and # 5 position (neck pickup alone). When in the # 2 and # 4 position the two combined are actually parallel-in-phase with each other. Normally all three pickups in a Strat are all wound in the same direction (clockwise looking from the top of the bobbin) and all magnetized either all North or all South in one harness. If the pickups are out of phase especially when trying to combine different pickup models from different manufactures you can have pickups out-of-phase and you can tell because they sound very thin, low output and lack fullness.
If all three pickups have 6,000 ohms dc resistance or 6 K ohms and two are used together in parallel (the # 2 and # 4 position on the 5 way lever switch) the dc resistance divides in half and becomes 3K ohms dc resistance. For many years now players have been putting 5 way lever switches into their instruments to get two extra tones. Hendrix used a 3 way switch and would balance the lever between the two positions to get the pickups in parallel with each other. In 1968 I gave Jimi Hendrix and Roger Mayer (Jimi’s tech) a bunch of old Fender Pickups I rewound and 3 way lever switches I knotched to stay in the 2 & 4 position easier. In return Jimi gave me a bunch of strings, back plates, springs, scarves and autographs. I took several photo’s of him and we talked about guitars and he showed me several of his guitar tricks. He enjoyed experimenting with his instruments and several Strats for different effects. He used to pluck his springs and lower his tremolo arm for effects. I was glad I had a chance to meet and talk with him. I’ll talk more about Hendrix in a later article.
Example of dc resistance using a standard 5 way lever switch:
1st position Bridge Pickup = 6 K ohms
2nd position Bridge & Middle Pickup = 3 K ohms (in parallel)
3rd position Middle Pickup = 6 K ohms
4th position Middle & Neck Pickup = 3 K ohms (in parallel)
5th position Neck Pickup = 6 K ohms

146. What is bi-polar winding? Can a guitar pickup be wound that way? Richard Benson, Iowa
This is a winding process I have been doing since 1977 when I built pickups for Jeff Beck. I used two different types of magnet wire and wound them both at the same time. I experimented with both beginning wires connected together and then decided to hookup each seperately to do some fancy wiring combinations. I had two beginnings and two finish eyelets to run the lead wires from. You can use a 43 gauge and 44 gauge single build magnet wire and wind them both simultaneously using the same number of turns. I remember using about 7,000 turns or till the coil was quite full. Winding with two wires is actually like winding 14,000 turns of one continuos wire. You will get two different dc ohm readings from each coil that give you two different tones. The coil using 43 gauge of magnet wire will sound brighter than the 44 gauge which will have more dc resistance. You can hook them up singularly or in series combining the dc resistance of both coils or put one of them out of phase with one another. With all the experimenting I’ve done over the years there are still many combinations of things to do with pickups.

147. When you rewind a pickup do you always have to remove old coil and replace it with new magnet wire? Andrew Kastner, Los Angeles, California
When I repair or rewind a pickup I will always try to remove wire on external breaks and spice the broken magnet wire. After I find the break I carefully sand the insulation off with fine sandpaper, solder the connection, insulate and rewrap putting the removed turns back on. After other evaluations if I find the coil non-functional due to either magnets being moved within single coils or I detect Inner Coil Pole Corrosion (ICPC) (when the magnet and coil corrode inside the beginning of the coil). I carefully remove the existing coil turn by turn till I get to the internal break, splice and rewind using the same magnet wire. This is the proper way coils should be repaired and rewound. The old wire can be saved if the guitarist wants a completely different sound out of his pickup. I don’t like rewinding stock old pickups just because the player wants a new sound. They should seek out another pickup to modify or experiment with. You can find newer Fender or Gibson style pickups to experiment with at music stores or repair shops that install pickups or do custom work.

148. What are the plastic materials used for making various pickups and guitar hardware? Paul Bromwell, Kentucky
Polymers are plastics used for Injection molding, thermoforming, extrusion, casting and film or sheets. Below are the common plastics used from guitar pickups to accessories.
ABS: is a thermoplastic with good impact resistance and compressive strength.
Acetals: are thermoplastics with applications similar to nylons. Has high impact resistance and ultraviolet radiation causes surface damage.
Acrylics: are usually transparent thermoplastics also known under the brand name as Plexiglas.
Butadiene Styrene: this is a very cheap plastic and has poor resilience and fatigue strength.
Cellulosics: this polymer encompasses cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose nitrate and ethyl cellulose. Cellulose nitrate becomes brittle (early pickguards) and burns rapidly. Ethyl cellulose has low flammability.
Epoxies: the epoxy resins are thermosets when cured. They are used with glass fibre to form composites.
Melamine formaldehyde: this resin when thermoset is used for making old bakelite knobs used on older amps. The material is commonly colored black and red.
Phenol formaldehyde: this is a low cost molding powder and has low cost and good heat resistance.
Nylons: this is a thermoplastic material used for making many Gibson Firebird, EBO Bass, and Fender Humbucker bobbins. The common nylon is nylon 6, nylon 66 and nylon 11. They are translucent and medium stiffness when glass fibre is added. The nylons can absorb water thus they can be dyed various colors with RIT dye.
Polyethylene: is low and high density and low being weaker and softer and the high being stringer and stiffer.
Polypropylene: a thermoplastic with low density. Additives are used to modify the properties and has reasonable strength and stiffness.
Polystyrene: a transparent fairly brittle and yellows in sunlight.
Polyvinyl: the thermoplastic and includes polyvinyl chloride (PVC)

149. Can bobbins made from different materials change the sound of a pickup? Jeffrey Dunn- Maple Shade, New Jersey
I am currently doing research on this one and am winding bobbins made of different materials to see how it affects the inductance or Q of the coil. I know plastics have different a dielectric constant and I am working on how it affects the sound of a pickup.
Below is the dielectric constant of various plastics used in making guitar bobbins.
Plastic Dielectric Constant
ABS 2.4-2.5
Acrylic 2.2-3.2
Cellulose acetate 3.4-7.0
Nylon 6 4.0-4.9
Nylon 66 3.9-4.5
Polycarbonate 3.0
Polypropylene 2.0
PVC, plasticized 4-8
Phenolic 4.4-9.0
The above chart giving various dielectric values is information is from the William Bolton Engineering Materials hand book. I know there’s a relationship between the plastics and the tone of a pickup though it be subtle or extreme, there is a relationship between them.
There are other ways plastics are used in making pickups and guitar parts.
Bobbins can be injection molded or fabricated from sheet plastic and hand fabricated. The old Charlie Christian (Gibson ES-150) pickups were hand fabricated. The bobbins on the early P-90 pickups were also hand fabricated. The “Patent Applied For” humbuckers designed by Seth E. Lover were injection molded from 4 different molds. The Gibson Melody Maker, Johnny Smith and Firebird bobbins were injection molded out of nylon. Still a good way of making bobbins is to stamp out flatwork from sheet plastics or phenolics and hand fabricate the bobbin to the desired shape. Many prototypes are hand fabricated this way and if the demand for a particular pickup is great enough then the manufacturer decides if they want to have an injection mold made. It cost much more for an injection mold but in a long run you have to decided if the labor for building the pickups will cost more than the cost of an injection mold. Injection molding can give you thousands of bobbins with equal tolerances and work well when machine winding multiple bobbins at a time. Hand fabricated bobbins work well with both automatic machine winding and hand or what I call scatter winding. Mounding rings used on the early Gibson humbuckers were also injection molded. The mounting rings for the Firebirds were stamped, polished and plated. Early pickup covers on Gibson P-90’s were vacuum or thermoformed. They take a thin sheet of plastic, heat it and shape it with use of a male cover form by pulling a vacuum. The cover is then trimmed of excess plastic. The pole piece holes can be drilled to the proper spacing by a drilling fixture. Most all pickguards are made from sheet material with the earliest material called Cellulose Nitrate. This was very dangerous to use and would be difficult to put out if it caught fire when routing or machining. Many beautiful Jazzmaster, Jaguar and Stratocaster pickguards were made of Cellulose Nitrate and had to be changed due to the extreme hazard of this material. Early acoustic pickguards were made of thin sheets of this material. I recently saw an old Telecaster where someone took a blow torch to the finish to remove it and got too close to the pickguard. I looked like a piece of peanut brittle when he got finished!!! Don’t do this!

150. How can you tell if a pickup is hand or machine wound? Ed Durham, Dallas, Texas
A hand wound pickup means the magnet wire is guided on by hand which I call scatter winding and the magnet wire is layered back and forth as the bobbin turns. The machine wound or automatic traverse guides the wire back and forth at a pre-determined pitch. The pitch determines the turns per layer on a particular coil. Coil machines can be variable with the turn of a knob or permanent by use of gears. Variable pitch works better when using various gauges of magnet wire and the permanent pitch gears work well when using a single gauge of magnet wire especially when winding production runs of the same coil. To determine if a pickup is hand or machine wound you would need to find some old broken pickups that you can experiment with. Don’t use any working pickups that can still be used but often I find old broken ones in a junk box at a music store. I find most humbucking pickups manufactured have the coils machine wound because two are needed in each pickup so it’s best to have the coils matched equally in both number of turns, pitch (turns per layer) number of layers and tension. As you unwrap the magnet wire turn for turn the wire will eventually make a pattern back and forth. I count the turns per layers in one direction and then the other. After a while if you see a consistent pattern, this usually confirms the coil is machine wound. If the coil turns are haphazard and have a inconsistent number of turns per layer this usually confirms the coil is hand wound.
Many guitar companies have production houses wind their pickups for them and others use pickups made custom for them by other popular pickup manufacturing companies.