In the beginning…
It would be said that the birth of rock and roll came about thanks to the invention of the electric guitar and amplification. The guitar pickup was a major part of this equation. The first electric guitar pickups were single coil pickups. They are known for their clear tone and clarity, but there is was a drawback to the design – the noise. Single coil pickups have a bad habit of picking up electromagnetic interference from mains power, whether it come from general wiring, lighting, or transformers and motors, just to name a few factors. No matter how well a guitar’s electronics cavity is shielded the electromagnetic interference, otherwise known as 50 or 60 cycle hum (depending on the mains power specifications of a country or region), it was still an issue for players cranking up their amps. Someone needed to come up with a solution, and the man for the job went by the name of Seth Lover.
The Birth of the Humbucker
In the 1950s there were two guitar companies dominating the electric guitar market – Fender and Gibson. Both companies had designed single coil pickups of varied designs for their guitars, and Gibson was looking for a way to get an edge over their competition. The way they could get this edge was to produce high quality low noise pickups.
Back in the mid 1950s Seth Lover was working in the guitar amplifier division at Gibson. It was during this time that Lover worked out a way to wire two single coil pickups in series, rather than parallel, electrically out of phase and with reversed magnetic polarities. This configuration made the noise of each individual coil cancel or “buck” the hum produced by the other coil before it even made it to the amplifier. This is how the name “humbucker” came about.
On the surface the initial prototype differed quite a bit from the production version. The prototype bobbins were made from celluloid, with fixed iron pole pieces in each bobbin. The original prototype bobbins were made from celluloid and acetone, mixing celluloid chips with acetone until the mix was in a pasty form, then molded into the bobbin shape.
The cover was originally a flat plain cover. Lover didn’t want to have adjustable pole-pieces as he didn’t feel that the adjustments would provide much difference in the tone when adjusted. Lover decided to stamp fake pole-pieces on the cover, but Gibson was still not happy with this as they saw adjustable pole-pieces to be a big selling point. Lover ended up designing one adjustable pole-piece coil, and one fixed slug coil.
The addition of the adjustable pole-piece coil led to questions regarding the positioning of the adjustable coils. Lover decided that for the production versions that the bridge adjustable pole-pieces should be closest to the bridge, and the neck ones closest to the fretboard.
Lover officially filed the patent for his new pickup design in June of 1955, and Gibson added the PAF pickup to their lap steel guitars in 1956, followed by a range of electric guitars in 1957. The “PAF” name comes from the abbreviation of the words “Patent Applied For”, which were stamped on the underside of the early pre-patented pickups. These early “P.A.F” labelled pickups are the most collectable and desired pickups, and can fetch hefty sums of money amongst vintage guitar collectors. The patent was finally granted in 1959 (U.S. 2,896,491)
When the patent was finally issued Gibson put the patent number 2,737,842 on the bottom of the humbucker. This was obviously not the patent number for the humbucker. The number that was put on the PAF was for the early tailpiece design used on the 1952 model Les Pauls and other acoustic-electric instruments. Lover believed that the stickers were mixed up, and when the order was made to put the patent notices on the PAFs somebody grabbed the wrong ones out of the stock room and the rest was history.
Putting it all together
Looking at the outside
Most PAF pickups have a brass cover with nickel plating. The earliest 1956 models are known to have a brushed stainless steel cover. The cover had good shielding properties, important for reducing hum. Some of the earliest PAFs weren’t stamped with the “Patent Applied For” marking, but are still considered the real deal.
The marking itself features a distinctive gold lettering on a black background bordered with the same golden line. Due to the age of the original pickups, the letters have a tendency to turn slightly green.
Lover recognized that to get the best performance out of the PAF that the bottom plate had to be made from a non-magnetic material so that it did not mess up the magnetic field. The magnetic field needed to go from the magnet, up through the pole-pieces to the strings. Nickel Silver was chosen for the bottom plates for this purpose.
Lover also chose to use brass screws to attach the bottom plate to the bobbins, again ensuring that the magnetic field was not disturbed in any way. Later PAFs have been known to be produced with steel screws.
The mounting legs were designed with an “L” shape to ensure maximum pickup adjustment. If the legs had come straight out from the side of the plate there would not have been enough room to fit the spring in and get an appreciable pickup height adjustment.
Important note: While on the subject of the PAF’s interior, it is of great importance to stress that under no circumstances should the cover be removed from a PAF. Such action will severely deteriorate the pickup’s value. If an inspection is needed, unscrew any of the bottom screws and look through the gap made by the loosened screws.
PAF Magnet Specs
Initially, the length of a PAF magnet was approximately 2.5’’ with a 0.5’’ width and a 0.13’’ thickness. By 1961 there were some changes and the length of the magnet was reduced to 2.25’’. The “short magnet PAF” also saw the width and thickness reduced to 0.49’’ and 0.12’’, respectively.
In the beginning Gibson randomly used an assortment of Alnico type magnets in the production of the PAF pickups. Alnico is an abbreviation of the metals used in the construction of the magnets, which are aluminum, nickel and cobalt. The grades of Alnico are identified by a number, which in basic terms gives an indication of the strength of the magnet, created by the particular blend of the metals used.
Gibson used a range of Alnico 2 to Alnico 5 magnets which is one of the factors in why there is such a large inconsistency attributed to the tone in early PAF pickups. The most common type before the standardization of the magnet was Alnico 4.
In 1961 Gibson settled on using Alnico 5 magnets in the production of the PAFs. This in conjunction with the move to the shorter magnets significantly lowered the inconsistencies previously found in the PAF pickups.
The north pole of the magnets were always marked with a black line so that when the magnet was installed in the pickup all of the pickups would have the same polarity.
Lover also designed the production model bobbin, which was made out of butyrate, rather than celluloid like the prototype. There was a discussion about making different spaced bobbins for the bridge and neck PAFs, since the string spacing at the fretboard end is narrower than the bridge. The final decision was compromise and stick with the one bobbin size.
PAFs were wound with purple #42 plain enamel wire in the initial stages. Lover chose 42 AWG plain enamel wire due to the economics of making the pickups. 44 AWG was more likely to break, and the additional DC resistance that the thinner wire could have provided was not considered too important at the time. A thicker gauge like 40 AWG wouldn’t have been able to have enough turns on the coil to provide enough output.
There wasn’t an exact process with regards to the amount of winds each coil had on the PAF. The aim was to wind as many turns as possible to fill the bobbin and then stop.
The coil windings were then wrapped with #4 flatback insulation tape, this was for mechanical protection, to ensure that the coil windings would not be damaged.
Early PAFs were manually wound, resulting in resistance readings varying from 7.5 to 9.0 KOhms. This was the other major factor in the inconsistent tone of early PAFs.To save costs Gibson switched to polyurethane-coated wire around 1963. This change is typically identified by the red colour of the bobbin wire.
By 1966 Gibson had switched to the Leesona 102, an automatic pickup winding machine. This enabled them to wind pickups with greater consistency. They aimed for a total DC resistance of 7.5KOhms, but since the Leesona’s automatic balancing system was a little fragile there were often unbalanced windings. These unbalanced windings resulted in some coils measuring as much as an entire KOhm difference between the pair. Rather than this be a detriment, the differences allowed some frequencies to leap out, making these pickups sound extra special.
The pole-pieces and slugs were both made of soft iron and plated to keep them from rusting. Lover designed the spacer for the pole-pieces to not only surround the screws with the magnetic field, but also hold the screws tightly in place. If the screws went into plastic the materials would wear too easily.
Lover designed two different sized mounting rings to suit the slope of the strings. This ensured that the string height was nicely balanced with the pickups and the output would be nice and loud. Lover thought that he have to put in two screws on each side of the PAF to get the slant right, but the pickups tended to take on the angle of the ring with the cover on.
Usually called the M-69, the pickup rings featured on the PAF were either black or cream. The rings came with two different markings – the thicker bridge pickup rings were marked “MR470″and the thinner neck pickup rings were marked “MR491″. The black-ringed PAFs occurred more often, as the cream models were used solely for the Gibson ES-295 and Les Paul models.
Positioning of the pickups on a guitar
The process of positioning of the PAFs on guitars was mostly trial and error. Initial placement was based on the placement of the existing single coil spec pickups and then moved back and forth a little until the right spot was found. For example, placing the pickup closer to the bridge resulted in a brighter sound, but there was a tendency to lose volume since the string vibration didn’t move as far as it did further along the guitar.
String gauge size and affect on pickup strength
The PAF was designed in a time when the smallest string gauges were typically found with a 12 gauge high E. As the years when one and smaller string gauges became more common people have complained of weak PAFs, but this is most likely due to the player using a lighter string gauge. The lighter strings aren’t able to move the magnetic field of the pickup as much as larger gauge strings can.
Jazz Guitar Edition PAF
While the bridge PAF design was shared by both solid body models and ES series guitars, the neck versions differed between the two types of guitars. The neck model had a narrower string spacing to match the ES series guitar’s narrower neck. The color of the pickup covers on the ES series usually came in gold, matching the rest of the hardware on the guitar.
Bobbin Color Variations
Under the covers there were three major bobbin colour variations used throughout the production of the original PAF pickups:
Double Black PAF
The first PAFs were produced with double black bobbins. An original early all-black PAF can be identified by the use of the copper coil wire with a distinctive purple-like hue. Differences between the adjustable coil and fixed coil are also noted, with the fixed coil featuring a larger circle. Many reissue PAFs try to emulate these features, but the natural aging process and some of the older models distinctive characteristics make the originals easily recognizable.
As the name indicates, zebra PAF pickup features two differently colored bobbins, with one being white and the other black. The zebra PAFs were initially introduced during the early 1959 with the black bobbin being the adjustable coil in almost 100 percent of the cases.
Double cream PAF
Featuring two cream bobbins, the double cream PAFs were introduced around the same time as the zebra pickups. The use of cream bobbins stopped by the mid-60’s, with the company turning all PAFs to double black models.
There was no conscious decision to use cream bobbins during these periods. It was likely that the supplier called up at one point in time and advised that they were out of black material, and would make the bobbins out of the cream material. When the pickups were made it was have been random selection that resulted in some PAFs having zebra (black and cream) or all cream bobbin construction.
Gibson Guitars Using PAF
Although the iconic Gibson Les Paul is without a doubt the most famous Gibson guitar ever produced to have used the PAF pickups, several other models stand out and are definitely worth mentioning. The PAF models are as follows:
- Gibson Les Paul
- Gibson ES-175
- Gibson ES-295
- Gibson ES-350
- Gibson ES-335/ES-345/ES-355
- Gibson ES-5 Switchmaster
- Gibson Byrdland
- Gibson L-5CE
- Gibson Super 400
PAF Changes Timeline
From the first introduction in 1955, the PAF underwent several significant changes.The following summaries listed below are a good reference point on how to date PAF pickups.
1956 – fall of 1957
When the original PAF first hit production it featured the aforementioned long magnet and there was no signature “Patent Applied For” sticker.The pickup consisted of black lead on each of the two coils, double black bobbins, stainless steel covers and Philips base screws. Purple enamel wire was wrapped around the bobbins and DC resistance varied from 7 KOhms to 9 KOhms. Featuring tool marks shaped as the letter “L,” the magnets had a standard length of 2.5’’, width of 0.5’’ and a thickness of approximately 0.125’’.
Fall of 1957 – 1960
The PAF sticker was added, but the pickup specifications largely remained the same as the original production run. The bobbin wire was still purple, the magnets were long, both coils had black leads, Philips base screws and nickel-made covers. Tool marks shaped as a letter “L” were still present, DC resistance still varied from 7 KOhms to 9 KOhms. Black bobbins were the norm, although some cream colored bobbins began to appear from 1959. The covers were of the nickel coated brass variety.
1961 – 1962
It was during the summer of 1961 that the short magnet PAFs were introduced by the company. The “Patent Applied For” stickers were still present as was the purple enamel wire, Phillips base screws and L-shaped tool marks.The new short magnets had a length of 2.37’’, width of 0.5’’ and a thickness of 0.125’’.
1962 – 1965
The PAFs of this era still featured some of the classic PAF marks, including the nickel cover, Philips base screws, PAF pickup style bobbins and L-shaped tool marks. The red polyurethane coated wire was introduced around 1963, bobbins started appearing in the cream color and became flat instead of bowed.
The 1965 Gibson models featured the later “Patent No.” sticker, and the bobbin wire color was changed to orange. The covers were made from chrome and the pickups retained the short magnet specifications. Philips base screws were still present, but the L-shaped tool marks started to disappear. The pickups also had a single bobbin head, as well as consistent 7.5k ohms. Note that the L-shaped tool marks began to resurface around 1972.
1965 – 1975
The PAFs of the final era featured the “Patent No.” sticker and a “T” marked on the top of the bobbins. The T was to indicate the top of the bobbin, to help with the assembly of the pickup. These final PAFs are quite often called “T-tops”, but the important thing to remember is that there is no real difference other than the bobbin marking, and the T-Top is a PAF.
The orange bobbin wire was retained, as was the short magnet specifications. The bottom base screws were mostly slotted ones, but the Philips screws were still sometimes used.The hole in the bobbin giving the view of the wire was no longer present, while the L-shaped tool mark can only be seen on the early T-top models.
Purchasing original PAFs
When it comes to the actual purchase of the used Gibson humbuckers, the buyers often go for the “Patent No.” stamp with the closed (unopened) nickel cover. Such an approach had proved itself as the safe one and most likely gives the buyer a solid guarantee that the pickup will be of high quality and at a decent price. The Patent# pickups are generally an excellent value, seeing that their sound is rather close to the original PAF models, but come at a much cheaper price.
The chrome-covered pickups on the other side, are bit more of a shot in the dark, seeing that the buyer can never be fully certain on what exactly they will find inside. There’s a good chance that they might get a T-Bucker, but there are no guarantees. Therefore, such a purchase should usually be avoided, unless the price is too low or tempting to refuse.
Seeing how iconic the PAF magnets have become, it doesn’t come as much of a surprise that forgeries occur relatively often. Although the differences between the original and the fake PAF can be detected when the two are taken up against each other, some of the forgeries have proven themselves good enough to fool careless buyers. When it comes to fake models, most attention is given to the physical appearance and the “Patent Applied For” stamps. As previously noted, the distinctive features of the original PAF sticker are the golden letters and border rounding up the black background.
Pickup Ring Forgery
To give a better insight on how to detect the fake PAF rings, it’s best to explain how the forgeries are, made through the use of RTV silicone rubber molds. Essentially the forgers place the silicone mold around the original part and then remove the original part once the silicone is cured. The removal is followed by filling of the mold cavity with liquid urethane resin that produces a very similar pickup ring once cured.
The process results in a perfect match of the original ring, down to minute details like the original ring’s surface scratches. Therefore, the fake rings are often successfully sold by the forgers for the price of an actual genuine Gibson ring.
Several distinctive features single out the M-69 rings as identifiable, as they cannot be made through the use of a machined steel mold. One such feature is the so-called “funneled” screw boss mount located on the lead pickup rings which can be found on every original M-69.
Once the new fake rings are produced, the silicone mold used in the process seems worn and of low quality. One of the indicators of such state are the cavities formed around the bosses by silicone webs. The silicone molds mentioned beforehand are usually used for producing between 10 to 20 parts, after which they tend to become fragile and unusable.
So although it may be hard to discover the fake pickup rings without the initial knowledge of the forgery technology, it becomes less of a problem once the basic fields are well covered. Another approach some of the forgers use is the sanding of the rings, which was actually something even Gibson occasionally did in order to make the so-called medium height pickup rings for numerous ES models, making the forgery much more difficult to detect.
Saying that there is a “PAF sound” is an oversimplification when talking about the iconic pickup. There are a number of factors to take into consideration when decoding the PAF sound. Due to the manufacturing inconsistencies throughout the PAF’s lifespan there is a range of tones that people experienced. Magnet selection and varying DC resistance shifted the sound from pickup to pickup.
The main components of the tone would be considered consistent would be the lower output compared to many modern humbuckers, and a fairly open tone with plenty of articulation.
Replicating a classic
Once the ‘80s arrived, an entire market for the vintage PAF pickups had emerged, leaving Gibson with a set of new business opportunities. Engineer Tim Shaw was called in to conduct thorough research and produce a reissue edition of the classic PAF pickup. For the first time, the company started producing Les Paul guitars based on vintage specifications. These guitars were later dubbed “pre-historics,” as they were the predecessor to the “Historic” reissues that the Gibson Custom Shop started creating in the 1990s.
Shaw’s initial research was brought to a standstill as his attempts to re-create the classic PAF proved too expensive under the then current Norlin owners. The engineer ultimately managed to rebuild the bobbin without the T-shaped tool mark used in the ‘70s. Apart from placing the proper square hole and successfully using the magnet of the same thickness as the PAF, Shaw figured out that the wire used in the initial PAFs was enamel. Despite making progress in his research, Shaw was set back once again as the enamel-coated wire were about $1 a unit more expensive than the kind Gibson normally used.
Shaw managed to reach Seth Lover, the original PAF designer, and discuss the production process and the specific parts used back in the day. Despite not reaching the desired goal, Shaw’s efforts resulted in a significant progress towards unlocking the secret behind the original PAF pickups.
Seymour Duncan and Seth Lover
Seymour Duncan is one of the aftermarket pickup industries pioneers. Making a name for himself in the late 1960s while working in London at the Fender Soundhouse, Seymour repaired and re-wound pickups for artists like Jimmy Page, Eric Clapton, David Gilmour, Pete Townshend, George Harrison, Jimi Hendrix, Peter Frampton and his guitar hero Jeff Beck. It was through his work with Beck that Seymour Duncan really began to hone his skills at winding pickups, learning the ins and outs of pickups such as the PAF pickup.
After spending several years in London Seymour moved back to the United States and settled in California. He made contact with Leo Fender, Les Paul and Seth Lover, and continued to learn the art of making pickups. Demand for his custom pickups grew and in 1976 he and his wife Cathy Carter Duncan started their company, Seymour Duncan pickups.
Seymour spent considerable time with Seth Lover during this time and considered him a mentor. It was through Lover that Seymour learned the fine details of the PAF pickup (including being given the original PAF prototype), helping him to design many of his most popular humbucker pickups. Co-incidentally, many of the PAF style pickups created by Seymour Duncan were wound on the same Leesona winding machines used by Gibson back in the PAF production days. Below is a list of PAF pickups created by Seymour Duncan.
SH-1 ’59 Model
The first PAF inspired model that Seymour created would be the SH-1 ‘59 model. Like the originals, the ’59 model includes plain enamel #42 gauge coil wire, long legged mounting plate and vintage style braided single conductor lead wire. DC resistance for the ’59 Model lies within the PAF specs, with the bridge model reading 8.13 KOhm and the neck at 7.43 KOhm.
The ’59 Model offers late-50’s vintage style humbucker sound with warm, crystalline clean tones and full, bright distorted tones. Wax potting ensures that the ’59 Model does not suffer from microphonics and works great for those classic rock tones.
The SHPG-1 Pearly Gates is named after ZZ Top guitarist Billy Gibbon’s favorite guitar, a 1959 Les Paul Standard. In the 1970’s Gibbons came to Seymour and asked for some pickups to be made so that his other stage guitars would sound just like his favorite axe. Seymour created a special set of pickups with a slightly hotter than average PAF output, using an Alnico 2 magnet, and DC resistance of 8.21 KOhm for the bridge and 7.3 KOhm for the neck model.
Tonally, the Pearly Gates provides a sweet, but slightly rude sound with great sustain. Its bright top end helps make harmonics leap out of the guitar, which is a good thing when Gibbons is known for his particularly good use of pinched harmonics.
SH-55 Seth Lover
In 1994 Seymour Duncan embarked on a project with PAF creator Seth Lover to build a faithful recreation of the original PAF. Lover handed down all of his notes on the design and construction of the PAF to Seymour, giving Seymour the ability to build the closest thing to the original pickup.
Using period correct parts like butyrate plastic bobbins, #42 gauge plan enamel coil wire, nickel silver long-legged bottom plate, Alnico 2 magnet, and even black paper tape and maple spacer, the Seth Lover is the closest you can get to the original without spending thousands of dollars. The bridge model has a DC resistance of 8.1 KOhm and the neck is 7.2 KOhm. True to the original design, the Seth Lover is not wax potted either, which gives it a very airy and open sound that is great for blues/rock and jazz, or just about anything but standing in front of a high-gain amp which may cause microphonic issues.
Designed to look and sound like a well used original PAF, the Antiquity line comes in Antiquity bridge and Antiquity neck versions. #42 plain enamel wire is wound around butyrate bobbins and have slight variations in DC resistance, just like the original early model PAFs. The bridge is wound a little hotter to balance nicely with the neck model and the magnets are degaussed to emulate an old magnet that has lost some of its magnetism. Like the Seth Lover model, the Antiquities are not wax potted.
Custom Shop Joe Bonamassa signature humbuckers
Blues maestro Joe Bonamassa wanted to replicate the tone of his beloved 1959 sunburst Les Paul. He went to Seymour Duncan and asked if it would be possible to make a pickup set that could give him the tone of his ’59 in any of his other Les Pauls. The Seymour Duncan Custom Shop created for him a set that used period-correct butyrate bobbins, wooden spacer and lightly aged nickel covers, with the bridge model powered by an Alnico 3 magnet, and an Alnico 2 magnet in the neck model.
Seymour Duncan have made 1959 available to the general public as a Custom Shop Joe Bonamassa pickup set with all sets already sold. Wound on the same Leesona winding machine, these pickups provide a rich, dynamic, and nuanced voice that would appeal to players looking for a sweet vintage humbucker tone.
The Seymour Duncan Custom Shop is able to help create custom guitar pickups of any description, be it P.A.F style humbuckers or anything else that the customer may imagine. The Custom Shop can even repair any old pickups like the P.A.F with the attention to detail and period correct parts to ensure that the pickup is revived to it’s former glory.
Remembering the man
Seth Lover passed away on the 31st January 1997, leaving the world with an amazing legacy. The design of the PAF, and subsequent humbucker designs have helped mold the sound of rock over the past 6 decades. It’s hard to imagine whether or not music would still sound the same today if it were not for the invention of PAF.