October 2001 Issue – A Few Secrets About Gibson PAF Pickups, with Lindy Fralin: Part 1

By Larry Meiners

The PAF legend was born during the recording sessions of amazing songs by Jimmy Page and his PAF equipped 1959 Les Paul, by the blues based tones of Mike Bloomfield and Eric Clapton and their Les Paul guitars, by the blazing guitar leads of Eddie Van Halen and his rewound PAF in his parts guitar, by the blues-based rock of Billy Gibbons of ZZ Top and his Pearly Gates flametop with PAFs, as well as other music artists. The PAF story has a life of it’s own. Some of the stories about PAFs are true, some myth and some created from outright poor conclusions. Not all original PAFs are made the same. Here’s part 1 of the PAF story:

The History
By the mid-1950s, Gibson wanted to counter the latest electric guitars introduced by competitors and especially those by Fender. Leo Fender had built a company from nothing in the mid-1940s to a substantial factor in the solid-body guitar market. Gibson believed they could beat Fender and other rivals for market share by developing a low-noise pickup. Players loved the sound of Gibson’s P-90 and Fender’s single-coil pickups, but they also put up with the 60-cycle hum (noise) inherent in their respective designs.

Gibson’s management assigned this important task to one of their engineers, the late Seth Lover. Seth’s subsequent design and patent changed guitar playing and music recording history. Let’s leave the heavy technical discussion for another article and understand the basic design: Seth connected two single coil pickups in series. However, he connected the coils out-of-phase electrically and magnetically. Thus, the signal is passes through the pickup minus much of the noise or hum. That is how the pickup Seth designed came to be known as the humbucker.

Gibson Humbucker Pickup Patent

Seth’s pickup patent was filed on June 22, 1955. Gibson added the new pickups to steel guitars in 1956, and in 1957 on electric solid-body and arch-top guitars, including the popular Les Paul Model. During 1957, a small black decal with gold lettering was added to the underside of the pickup. This decal read, “PATENT APPLIED FOR”. Later, as the vintage guitar market evolved from savvy recording artists to local musicians, these pickups became known as the ‘PAF’.

Gibson PAF Decal

Seth Lover received his approved pickup patent, #2,896,491, on July 28, 1959. By late 1962, Gibson changed the decal to read, “PATENT NO 2,737,842”. It is interesting to note that the patent number listed on the decal was not for the pickup design, but for Les Paul’s trapeze tailpiece. One can assume Gibson was creating a research roadblock for the competition. Or, was it simply a typo? The competition idea seems more credible, but silly, as these new decals appeared 7 years after the pickups were first installed on Gibson’s instruments.

Patent Number Decal

The Making of a PAF
Between 1959 and 1960, Gibson made PAF pickups with white and black plastic bobbins. Prior to this point in time, both of the bobbins were black. These oblong bobbins are exposed when the pickup’s metal cover is removed. Thus, some PAFs are referred to as double black (two black bobbins), zebra (one black and one white bobbin) and double cream (two white bobbins). Because collectors and players want the rarest possible instruments, amps, parts, etc… vintage double cream and zebra PAFs command higher prices that the more common double black pickups. These variations of PAF pickups with cream bobbins are also in their prime period of construction from 1956-1960. The bobbin’s color does not influence the sound of the pickups. It’s purely cosmetic, but creates a very cool image.

Double Cream PAF

From 1956 until sometime in 1961, Gibson used different Alnico magnets in their PAFs. Alnico magnets (composed primarily of the alloys ALuminum, NIckel, and CObalt) come in a variety of grades based on their magnetic strength. Gibson used the same magnets (size and grades) available for their P-90 pickups. It seems Gibson randomly used Alnico 2, 3, 4 and 5 grade magnets in PAFs until 1961. The higher the magnet’s number, the higher the magnetic strength. By 1961, Gibson began consistently using a smaller size Alnico 5 magnet. Generally speaking, decreasing the flat (top) side size of these magnets decreases the power of the pickups.

As for wiring, Gibson used a braided shield wire for connection to the control pot. The pickup bobbins were wound with #42 (plain enamel) wire. The bobbin wire appears purple versus later versions that appear reddish. Gibson eventually switched to polyurethane coated wire around 1963. The capacitance of the coating is determined by thickness and material composition, and this influences the sound of the pickup. When coatings change, the sound signature of the pickup can change.

The amount of wire (and coating) wound on each bobbin determines the DC resistance and other factors, including sound characteristics. When the bobbins are wound with more than a nominal amount of wire, the more power they exhibit, thereby sounding fatter in the midrange with less treble. The resonant peak of the pickup changes as more or less wire is used. Due to human intervention and the wide-tolerance of the winding machines and the test equipment used by Gibson from 1956-1961, PAF pickups during these years usually measure between 7.5 – 9.0 thousand ohms (K ohms). I have measured an original, unaltered 1960 PAF in the neck position of an ES-335 guitar at 10.0 K ohms! After 1961, almost all PAF and patent number decal pickups seem to measure 7.5 K ohms +/- .25 K.

PAF Magnet and Wiring

A Talk With Lindy Fralin
Now that we have a handle on the basics, let’s discuss various conclusions this information implies. I asked pickup guru Lindy Fralin to help us decipher some of the mysteries and the myths of the PAF pickup. Lindy Fralin runs Lindy Fralin Pickups, a company based in Richmond, Virginia. Lindy is a passionate pickup scientist who has spent countless hours trying to understand how all types of pickups were designed and constructed. He can discuss the entire technical subject spectrum about resistance, inductance and all the other pickup characteristics. In 1998, Lindy’s PAF humbucker was chosen as the best sounding pickup versus five other PAF-type models in a magazine product test. Let me relate to you some of Lindy’s thoughts on the subject of PAFs.

Lindy said that many of the original PAF pickups from 1956-1960 sound different depending on the magnet and the amount of wound wire. His preference is for the PAFs that used an Alnico 4 magnet, with approximately 8.0 K ohms. He said they sound a bit more robust with a better defined high-end. So Lindy uses the Alnico 4 in his version of the PAF humbucker. Lindy admits that theories regarding degraded wire coatings and micro-cracks in the wire of original PAFs have been discussed. However, these ideas have not been fully quantified as to the effect on the sound signature of original PAFs versus PAF-type pickups made today.

Lindy stated that the 1961-1963 PAF and the 1963-1975 patent number decal pickups are very consistent in sound and resistance at 7.5 K ohms nominally. They have the smaller Alnico 5 magnet and some have different bobbin wire. They sound different when compared to early PAFs with more high-end and less warmth, especially in the mid-range. Although some players prefer the sound of the later patent number humbuckers, including Michael Schenker of UFO and MSG. Michael’s 1971 Medallion and early 1975 Flying V guitars included these patent number pickups as standard equipment originally.

Another interesting fact Lindy mentioned was that when he measured original PAFs, many times, each side of the pickup’s double-coils exhibit a different value due to the manufacturing issues mentioned previously. For example, one side might read 3.5 K ohms and the other 4.5 K ohms. He said this often contributes to better sound, not worse. With slightly mismatched coils, certain frequencies are cancelled and others are phase-shifted. This results in a pleasing sound according to Lindy. Since Jimmy Page and Billy Gibbons won’t let you tear apart their pickups for analysis, we can only wonder if these historically significant guitars have mismatched PAFs. This is getting interesting.

Lindy believes so strongly in the mismatched coils idea that he created a new pickup called the UNBUCKER. He said this design was developed because of the lack of clear high end on the wound strings of most side-by-side two coil pickups. The sound from a humbucking pickup is created by string vibration being sensed in two places (two coils) rather than one. He says the UNBUCKER creates a humbucker that looks normal but sounds brighter on the wound strings.

The other point Lindy mentioned concerns the pickup’s efficiency. If a pickup design is efficient, it will capture most of the frequencies the guitar is producing and be loud. The trick for all pickup designers is to make an efficient pickup with a pleasing frequency spectrum.

Zebra PAF

Exploding A Few PAF Myths
1) All PAFs sound the same – Definitely not. The changes in construction and materials ensure that some PAF pickups were made outside of the normalized average. PAF pickups will sound different in different guitars as well. Various wooden guitars absorb certain frequencies and resonate others.

2) Higher resistance PAFs sound better – Not necessarily. Other factors affect the sound, including capacitance, inductance and pickup efficiency. Also, higher resistance pickups tend to have lower high frequency response.

3) PAFs sound better because the magnets have weakened – Guitar magazines articles in the past have reported that the ageing of the magnets over 40 years has changed them and produced a better sounding PAF. However, magnet manufacturers report that these Alnico magnets only lose 0.2 – 2.0 % of their strength over 100 years. It’s not weakened magnets. Beck, Clapton, Page, Gibbons and the other PAF guitar players made a bunch of great music with these instruments in the late 1960s when the pickups were only 10 years old. If the ageing story made sense, 1970s Gibson humbucker pickups should sound wonderful with 20+ years of ageing, but they still exhibit less warmth with more high-end than PAFs.

Just buying a PAF won’t ensure you sound like Jimmy Page, Eddie Van Halen or Billy Gibbons. Other factors play a part, including the aforementioned players great talent. Also, the amplifier, string gauge, action set-up and the resonance of a particular guitar also factor into the equation.

Seth Lover’s humbucker pickup is an efficient and beautiful design. Yes, some of the wiring and coatings are made different today and don’t replicate the processes of the 1950s. Still, I think the leaders of the replacement pickup market, including Lindy Fralin, Seymour Duncan, Tom Holmes and others make great PAF-like pickups that probably get you 80-90% of the sound of the original PAF for 10% or less of the cost of a vintage pickup. However, there will always be individuals that will pay for the real PAF because they want the thing everyone is copying. You decide which pickup fits your needs and budget.

In Part 2 of the PAF Story, we will discuss how pots and capacitors change the sound of your pickups. How your sound changes by removing the pickup cover. Also, how the set-up (action and pickup height) changes the tone. We will also discuss the T-Top patent number pickups that followed the PAFs. Stay tuned!

Thanks to Lindy for his help with the article. Please visit his website at: http://www.fralinpickups.com/
Copyright © 2001 Larry Meiners All Rights Reserved