PAF Humbuckers Explained: What the Patent Applied For Pickup Really Was

“PAF” is one of the most used and least examined words in guitar gear. It stands for “Patent Applied For,” and it was a sticker on a pickup before it was a name. Gibson put it on humbuckers while a patent was pending, players started using it as a name, and by now it is shorthand for a whole sound, a whole price bracket and a lot of marketing copy. The facts underneath are thinner and stranger than the shorthand suggests, and the patent number that ended up on later decals appears, on the evidence below, to belong to a different invention altogether.

Here is what PAF humbuckers actually were, what is inside them, why no two originals are alike, how PAF-style pickups differ, and what you can and cannot establish about one before buying.

Where the PAF Came From

The humbucker is usually credited to Seth Lover, a Gibson engineer. According to Guitar.com’s history of the pickup, Lover rejoined Gibson in 1952 and Ted McCarty started the project to design a noise-free pickup in 1955; Gibson applied for its patent that June. Guitar Player’s account adds that McCarty assigned Lover and Walter Fuller to the job, and describes the result as a P-90 turned into a two-coil unit: two similar coils wound in opposite directions with opposite magnetic polarity, side by side and wired in series, so that hum picked up by one coil is cancelled by the other.

Lover gave his own version in a 1978 interview with Seymour W. Duncan, transcribed in 1995 and later posted by Seymour Duncan. He recalled that McCarty asked for a new pickup around 1954 or 1955 and that he proposed one that would also eliminate hum near amplifiers. He also recalled that production followed only after a competitor showed a humbucker at a trade show and management pushed to get one into guitars. That detail comes from Lover alone, years after the event, so treat it as his recollection and not as settled history.

The timeline of the first guitars varies by source. Guitar.com puts humbuckers on Gibson steel guitars in 1956 and on the Les Paul and archtops in early 1957. Gibson’s own legacy pickup guide says Gibson introduced the humbucker in 1957. Lover remembered the ES-350 getting one first, then the Les Paul, then the ES-335, around 1956 to 1957. Our Gibson ES-335 guide covers the semi-hollow launched in 1958.

The Patent Number Mix-Up

Two patent numbers circulate in PAF stories, and they are not the same thing. Google Patents lists Seth Lover’s “Magnetic Pickup for Stringed Musical Instrument” as US 2,896,491: filed June 22, 1955 (Serial No. 517,171), assigned to Gibson, Inc., and granted July 28, 1959. The patent describes two coils on opposite sides of a magnet, joined so that hum voltages in the two coils oppose each other while the signal from a vibrating string adds. Lover himself named 2,896,491 as the humbucker patent in the 1978 interview.

The number 2,737,842 is something else. Google Patents lists it as “Combined bridge and tail piece for stringed instruments,” inventor Lester W. Polfuss, assigned to Gibson, filed July 9, 1952 and granted March 13, 1956. It does not describe coils or magnets. Guitar.com says the decal that replaced the “Patent Applied For” sticker in late 1962 carried an incorrect patent number. In Seymour Duncan’s 1978 interview, Duncan put it to Lover that the number on the humbucker, 2,737,842, belongs to the early tailpiece used on 1952 Les Pauls; Lover did not dispute that, said “I think they just got mixed up”, and recalled workers grabbing labels from the stock room and putting the wrong ones on. The match with 2,737,842 therefore rests on that interview question and the Google Patents record, not on a Gibson document we have seen. Either way, a “Patent No.” decal on a pickup of this period does not point to the pickup’s own patent. Lover also said it was possible Gibson had pickups made well ahead of use, so a decal does not reliably date a guitar.

Guitar.com dates the decal to late 1957 through late 1962, so it stayed on after the patent was granted in July 1959. Gibson’s legacy guide gives 1956 to 1962 for the originals, and Guitar Player says 1957 to early 1962. Anything tighter than “about 1957 to 1962” needs a source attached.

Specification: A Typical Original PAF

There is no single PAF specification, which is the point of this guide. The table lists what sources agree on and flags where they do not.

What Is Inside a PAF

The magnet

Lover said Alnico was chosen because it was small and strong for its output, though cast Alnico needed grinding to hold its dimensions. He also said he found less string-to-string imbalance than on older designs, which is why he wanted a plain cover with no adjustable pole pieces. Sales staff wanted a visible selling point, so adjustable screws were added. Which Alnico grade went into production is disputed in print. Guitar.com says A2 and A5 are the grades commonly reported, that some claim A4 was used, and that A3 is disputed. It also says the magnets were shortened by a quarter inch in 1961 when Alnico V became standard. Each is a single-publication claim, so none is a reliable way to date a pickup.

The wire and the winding

Lover said he used 42 AWG plain enamel wire, and that 44 gauge risked breakage while 40 gauge would not fit enough turns for adequate output. Lover’s recollections of turn counts ranged from about 4,200 to about 6,400, and he said he would have to take one apart and unwind it to be sure. He said the production winder had an automatic traverse, a separate tension setting for each coil and operators who judged tension by feel, and that a wire break could leave a coil 50 to 100 turns short; Guitar.com instead describes non-automated machines. Gibson’s legacy guide says coils were aimed at roughly 5,000 turns but wound until the bobbin was full, and that measured DC resistance on originals runs from about 7.2k to 8.8k ohms.

Guitar.com adds that the two coils were not evenly matched and credits the offset with the clarity of a good PAF. It quotes Matt Gleeson of Monty’s Guitars: “Maximum hum cancelling comes with maximum treble reduction.” In other words, perfectly matched coils cancel more hum and give up some top end. That is one dealer’s view (Matt Gleeson of Monty’s Guitars), and modern makers still make different choices about coil balance.

The cover, the plate and the screws

Lover said the covers were nickel silver, chosen for drawability, soldered on at final assembly, and that the cover provides electrostatic shielding, so removing it leaves a gap that allows coupling. He used brass screws in the bottom plate because he did not want to divert flux from the magnet.

Why No Two Original PAFs Match

Loosely controlled winding, inconsistent magnet grades and sixty years of aging all push the same way. Guitar.com cites differences in magnet grade, aging and coil winding as the reasons PAFs sound so different from one another. DC resistance does not settle the question either. A Guitar Player roundup of modern PAF-style pickups notes that DC resistance does not reliably indicate how powerful a pickup is or how it sounds.

Whether the best of them beat the best modern pickups is a matter of opinion. Guitar Player says the PAF became the template for most full-size humbuckers that followed, and that many enthusiasts consider it the most sonically prized pickup ever made, while noting that supply and demand inflate the prices.

PAF-Style Pickups Today

In our view, “PAF-style” has no fixed meaning. A maker decides which features of the original to copy, and the market uses the term for pickups that differ in output, magnet, potting and price.

Gibson. Gibson’s legacy pickup guide (an older page; current catalogue not checked) describes three routes. The ’57 Classic uses Alnico II magnets, matched coil windings, and wax-potted coils to reduce microphonic feedback; it is wound toward the lower end of the PAF range, and it carries a “Patent Applied For” sticker like the originals. The BurstBucker line, by contrast, uses unpolished Alnico II magnets and coils wound to slightly different turn counts, mirroring the inconsistency of the originals, and comes in three output levels. Gibson says the mismatch slightly reduces noise cancellation but adds edge. The BurstBucker Pro uses Alnico V and wax-potted coils with the same mismatched windings. Our guides to the Les Paul Standard ’50s, which uses Burstbucker 1 and 2 pickups with Alnico 2 magnets, and the Les Paul Studio, which has used several different pickup sets over the years, show how the names land on real guitars.

Seymour Duncan. The Seth Lover model (SH-55) is described by the company as a recreation of the original, released in 1994 in collaboration with Lover. It lists a 2.5-inch Alnico 2 bar magnet, 42 AWG plain enamel wire, a nickel silver cover and plate, no wax potting, and DC resistance of 7.4k (neck) and about 8.3k (bridge). The company’s blog does not say what technical work Lover did on it. The Antiquity version is hand-aged cosmetically and magnetically, per the company, at 7.70k and 8.60k.

Others. We have not sourced boutique makers’ claims for this guide. Guitar Player’s 2021 roundup of five modern takes notes that makers broadly agree on the essential construction of the originals but differ on method: some source the most accurate components and build to late-1950s Gibson practice, others voice by ear to match well-regarded originals. At the entry end, our Epiphone Les Paul Standard ’50s guide describes its ProBucker humbuckers as designed to replicate vintage PAF tone, and our PRS McCarty 594 guide says the 1994 McCarty, named for the former Gibson president, was voiced closer to a vintage PAF.

Comparison: PAF, P-90 and High-Output Humbuckers

Famous Guitars and What Sources Say About Their Pickups

A guitar’s fame does not by itself tell you which pickups it carries or how they were built. Only a few claims are sourced well enough to repeat. Guitar Player says the 1958 to 1960 Les Paul Standard is commonly considered one of the most valuable standard-production guitars, with PAFs arguably its most valuable single component. Our Les Paul Standard guide says the 1958 to 1960 Bursts used PAF humbuckers.

The best-documented pickup oddity in this territory is Peter Green’s 1959 Les Paul. Jol Dantzig, writing in Premier Guitar in 2011, said that in June 1984 he found with a compass that the magnet in one of the guitar’s pickups was reversed, and because the wiring and solder joints looked untouched he concluded it was likely a factory mistake. His article does not say the pickups were PAFs, so we will not either. The detail is covered in our Peter Green guitars and gear guide, which also notes that Green’s own accounts of how it happened varied. For a modern player, our Warren Haynes guide describes his Chester Les Paul in terms of Burstbucker pickups, not original PAFs.

Buying and Identifying: What Can and Cannot Be Verified

What “PAF-style” on a listing tells you

Very little on its own. It says the maker is aiming for a late-1950s Gibson humbucker sound, not what magnet, coil balance or potting is inside. Gibson’s legacy guide describes three different routes to the sound. Ask for the actual spec: magnet type, DC resistance, potting and cover material.

What you can check yourself

You can check that the pickup type fits the guitar’s era. Per Guitar.com, a “Patent No.” decal points to late 1962 onward and cites a patent that is not the pickup’s, and Gibson’s legacy guide says its ’57 Classic carries a “Patent Applied For” sticker, so it proves nothing in isolation.

What you cannot verify from a photo or a meter

In our view, DC resistance does not authenticate a PAF: Gibson’s own figures put originals at roughly 7.2k to 8.8k ohms, and Guitar Player’s roundup says resistance does not reliably indicate a pickup’s power or tone. In our view, decal wording, covers and magnets are features makers can copy or age on purpose: Gibson’s ’57 Classic carries the sticker and Seymour Duncan’s Antiquity is aged cosmetically and magnetically. We have not found a published method that settles authenticity from outside the pickup. If a set is priced like an original, treat a photo and a seller’s description as claims, not evidence, and get an independent appraisal.

Frequently Asked Questions