Published On: Fri, Aug 19th, 2011

Quiet Riot – The PAF Humbucker

If it wasn’t for one man and his work, our licks would still be rudely interrupted by buzzing, humming and general audio detritus. Rik Flynn discovers why Seth Lover, the inventor of the humbucker, deserves his place on the guitar podium of fame

 History is always going to remember the Leo Fenders and Les Pauls of this world thanks to the ease in which their eye-pleasing, iconic guitar designs slotted into popular culture and swiftly became enduring symbols of rock’n’roll. Pickups, on the other hand, were never likely to command quite the same level of adoration. While the designers of Fender and Gibson’s flagship instruments died heroes of the guitar world, Seth Lover – the man behind Gibson’s groundbreaking humbucker – could have slipped away from us penniless and forgotten, but for one man. 

‘Towards the last few years of his life, Seth was living in relative obscurity,’ remembers Seymour Duncan. ‘For me to say he lived a very simple life without much money is really putting things better than they were. When he was in his mid-80s, to supplement his meagre pension and social security, Seth worked delivering vacuum cleaners.’
Although enthusiasts were of course aware of Lover, most were (and still are) blind to the debt that we guitarists owe to him. It was not until Seymour Duncan came into the picture that Lover’s fortunes were reversed.
‘I feel I, along with my company, rescued Seth from that obscurity and let the music world know who he was and what his contributions were,’ Duncan continues. ‘Suddenly he was in advertisements and the guitar press was clamouring to interview him. Also, during his last three years, he had money for the first time thanks to the royalty checks he received from sales of the Seth Lover pickup.
‘I’m very proud of my relationship with Seth and what the Seymour Duncan company did with him during his last few years.’

Blast From The Past

It’s hard to imagine a world without the humbucker in an age when self-tuning guitars, built-in MIDI controllers and modelling technology have become commonplace, but prior to Seth Lover’s invention that’s the world guitarists were living (and humming) in. Much like any fresh idea it took a while to catch on, for the Gibson humbucker was a new competitor on the block joining a world still dominated by the single coil – the super-bright Fender guitar sound.
‘The PAF’s initial impact was moderate – Strat and Teles were already well established,’ explains Tim Mills, founder of Bare Knuckle pickups. ‘The main impact seems to come a little later, in the ’60s. Live music was getting a lot louder, so humbuckers really came into their own.’

Although Lover applied for his patent in 1955, he didn’t receive it until four years later. In the interim Gibson attached the famous ‘Patent Applied For’ decal on the underside of the pickups to scare off copyists, so Lover’s humbuckers became known as ‘PAFs’ (in 1962, the decal was replaced by a sticker that read ‘Patent No. 2,737,842’. Strangely, this number wasn’t for Lover’s humbucker at all, it was for Les Paul’s bridge/tailpiece; some suggest that this was an intentional red herring.) So, although mostly falling on deaf ears at their inception, PAFs have become the stuff of legend, fetching big money and hallowed as the Holy Grail of sound generators.
If you’re wondering what all the fuss about, just listen to Duane Allman and his sunburst Les Paul or Albert King and his Flying V in full swing, and all will become clear. In the words of Seymour Duncan, ‘this pickup changed guitar music for all time.’

Pickup Lines

Lover’s humbucker was by no means the first of its kind, hence the delay in granting the patent. The ‘humbucking coil’ was brought to the world by Albert ‘Al’ Kahn and Lou Burroughs of Electro-Voice in 1934. This duo were also among the first to use the now industry-standard ‘Alnico’ magnets (a blend of aluminium, nickel and cobalt). Kahn and Burroughs didn’t have guitars in mind, though, and while their story is an essential part of the picture, their invention was only ever used in microphones and PA systems.

Other humbucking concepts date back to the ’30s, and no less than six previous applications were waiting for Lover when he filed for his patent. Armand F Knoblaugh filed a piano pickup patent in 1935 which could be used for other instruments with vibrating steel strings. Although involving two ‘stacked’ pickups (with the core magnetising the strings) as opposed to placing them ‘side-by-side’, this design was well ahead of its time, and Lover certainly saw it.
On top of this design there were also those installed in lap steel guitars, like the beautiful 1930s art deco-inspired Vega that housed two pickups side by side. Regardless, Lover is the man synonymous with the humbucker, and his design is certainly the most influential. Tim Mills is testament to that; ‘It’s been the foundation of every humbucker design I’ve ever made,’ he says. Lofty praise indeed.

Silence Is Golden

Gibson’s own single-coils had developed fast since their unwieldy but great-sounding attempts of the mid-’30s. By the early ’50s, most Gibson electrics were based around the ‘Alnico’ model or the P90. When Gibson’s Ted McCarty asked Lover to begin work on a new pickup, he was keen. ‘I said, instead of just a new pickup, why don’t I make an improved one?’ said Lover. ‘Something the industry needs, which is get rid of the darn hum whenever you got close to an amplifier.’
Lover was able to use his experience with tube amplifiers that used a ‘choke coil’ – a transformer or coil that helped reduce the unwanted noise. With the ‘choke’ as his starting point, Lover developed a technique of wiring two coils in series but electrically out of phase with each other and with reversed magnetic polarities. In doing so he was able to ‘buck’ the ‘hum’. Lover also employed a ‘German Silver’ (copper, nickel and zinc) cover that helped reflect electrostatic noises from other electronic sources to help to quell the ‘60-cycle hum’.
Production PAFs, but not the prototypes, were fitted with adjustable threaded steel polepieces on one of the coils for fine-tuning the string balance. ‘Seth told me that Gibson’s marketing department wanted adjustable polepieces,’ states Duncan. ‘However, the prototype had cover indentations where the adjustable polepieces were intended to go on the production versions.’

Gibson announced their new creation in the Gibson Gazette as ‘the ultimate for recording, broadcasting or whenever truly fine performance is required,’ and it was finally unveiled at NAMM 1957. While the Les Paul Standard and Custom are the most famous of Gibson’s guitars to harbour PAFs, the humbucker was first used in Gibson’s steel guitars in ’56 and then introduced to some of their archtop models such as the ES-175, ES-295, ES-335, Byrdland, ES-5 Switchmaster, L-5CE, Super 400 and the ES-350T favoured by Chuck Berry.

Hum And Haw

PAFs aren’t all good. In fact, some really don’t cut it at all. ‘A lot of them can be quite one-dimensional,’ says Mills. ‘Others are head and shoulders above the rest.’ So what makes the good ones so damn good and the bad ones so disappointing?
 The answer is hardly straightforward. ‘Every component combines to make a good pickup,’ Duncan explains. ‘If you skimp on any of them, it’ll come back to haunt you in the end.’ As pickup guru Tom Holmes told Tonequest, ‘Everything makes a difference… but how much of a difference?’ And there’s the rub.

Some of the original materials were chosen for cost and availability as well as their sonic properties. For example, many guitarists fervently insist upon #42 gauge enamel coated wire, but as Lover states, it was specifically chosen ‘if you were doing something economically.’
To add to this, only the prototypes were hand-wound; production models were machine-wound with workers ‘hand-guiding’ the coiling process, resulting in differing tensions. The early winding machines also lacked counters or an auto shut-off mechanism, meaning inconsistent numbers of turns in each coil. Gibson did eventually install a fully-automated system in the mid-to-late ’60s leading to more uniformity in later examples (post-PAF), but the winding process alone had a profound effect on the end product.
PAFs from the late ’50s to very early sixties roughly measured between 7.5 and 9k Ohms, and later ’60s examples have measured as high as 10k. Higher DC resistance equals higher output; in other words, more wire, more volume. Overwound coils create more midrange and less top-end, so the difference is often marked. The two-coils-in-one PAF could often have different coil impedances too, which affected the sound considerably. Renowned pickup maker Lindy Fralin believed this mismatch improved the sound and began making his ‘Unbucker’ as a result, deliberately mismatching coils to create a brighter sound. Confusing the matter further, it’s possible that some PAFs were handwired. ‘Gibson had hand-winding machines for P90s, so it seems logical that these would be used,’ opines Mills.Lover remembers a few being wound by hand: ‘I wound sometimes, and if an old pickup was sent back in and they didn’t have a machine for winding it then it would be rewound by hand.’ So hand-winding certainly did take place – but on what scale is impossible to say.
The wire Gibson used varied too; Lover remembers using most of the major suppliers. ‘I wasn’t doing the buying,’ he continued, ‘just using whatever they’d get out of the stockroom.’ Wire tolerance can causes huge variations in output, and this certainly plays a part in explaining the wide spectrum of PAF tone.

Also, don’t forget that PAFs were designed with heavier gauge strings than those favoured today. ‘With heavier strings, you get more steel mass,’ says Duncan. ‘There’s more current being induced by the string vibrations.’ The sound is altered accordingly: ‘Bass frequencies get driven harder, producing a fatter tone with a rounder high,’ adds Mills. This means we’re experiencing a completely different pickup than the one Lover intended. ‘Some players say “my pickups are weak,”’ Lover told Duncan. ‘If they would only use a heavier string that the pickup was designed for, they wouldn’t have any problem.’
Then there’s the magnets. ‘Once it was thought that one of the reasons PAFs sound so good was that the magnet has slightly demagnetised over time,’ Tom Holmes told Tonequest. However, the sounds emanating from the guitar stars of the ’60s with their fresh, full-power pickups seem to suggest that this degaussing might not be a huge factor.
Does Holmes think the Alnico Gibson was using in the late ’50s was somehow special? ‘I’m not sure about old magnets versus new magnets,’ he says. ‘The manufacturing, heat-treating and magnetising processes have probably altered over the years… but how that relates to tone, I don’t know.’
Either way, the magnets used by Gibson were by no means identical. ‘We didn’t care about the thickness varying that much,’ said Lover. ‘One would be a little bit stronger and another a little weaker. You could live with that.’ Gibson sometimes even strayed from the original design. ‘Even though Lover stipulated Alnico V, Gibson continued to use existing stock of Alnico II and III bar due to the cost, later using Alnico IV and eventually Alnico V by late 1960,’ states Mills. ‘The different grades of Alnico all had a considerable effect on the tone.’

On top of all of these inconsistencies, the musicians testing the prototypes often picked up on different things to Lover and evaluated the prototypes differently. ‘We finally got to the point where you had to stop… you could have gone on forever and never been exactly perfect,’ he recalled.

Picking Up The Baton

There is little doubt that with PAFs Lover got the formula right, and the pros have gone to great lengths to decipher what makes these pickups tick. The question is whether or not such a seminal design can ever be perfectly replicated – or whether it could be even improved upon.
‘The fact that the basic principals of the pickup remain largely unchanged in over 50 years is testament to just how respected it actually is,’ says Bare Knuckle’s Tim Mills. ‘There’s plenty of scope to explore and enjoy new voicings, but I don’t think anyone wants to stray too far from the original formula. I use specially annealed mild steel for pole shoes and original electric steel for slugs and pole screws in humbuckers. All are made to the original dimensions, and the slugs and pole screws are nickel-plated to prevent corrosion. The effect of the heat treatment is more magnetism conducted towards the string for increased power and better definition.’

Tom Holmes has his own approach. ‘Since I’m a hand builder I can probably work harder to improve on cosmetics,’ say Holmes, ‘but Lover had materials manufactured in the ’50s and the tone he got combining these materials will never be duplicated by anyone. I can only do my best to assemble materials that are available to me today.’
Vintage PAFs were not scatterwound, and Seymour Duncan doesn’t scatterwind his replicas, but some makers do… such as Bare Knuckle. ‘Scatter-winding can only truly be done by hand and represents a high degree of skill,’ notes Mills. ‘It’s time-consuming, but it gives far superior tone and dynamics to conventional machine-winding and mass-production.’
Holmes also hand-winds his pickups. ‘The thing I work hardest on is the tension on the wire, using the feel of my fingers – I’ve been doing it for many years. The wire varies in size, as does the insulation. The age of the insulation and texture makes the wire feel a little different. I always end up winding a coil or two before I can get the proper feel.’
Duncan, on the other hand, remains true to the machine-wound technique. ‘I would never hand-wind a PAF-style humbucker,’ he says. ‘First, that’s not how Gibson did it. Second, in order to make a pickup hum-cancelling, the two coils have to be symmetrical. With hand winding, you lose that. Some builders hand-wind humbuckers. It could sound good. Or not. It’s not the way the originals were done. In my workshop we have the same Leesona Model 102 winding machine that Gibson used on the PAFs, but we put a digital counter on it with an automatic shutoff. That way we can be precise about the turns and consistent about the tone.’
The PAF’s cover is something that modern makers have also spent many hours arduously perfecting. ‘We designed the deep-draw tooling based on accurate measurements taken from several PAF covers,’ says Duncan. ‘We use the same “German silver” formulation that Seth used.’ Mills, too, has managed to replicate the formula. ‘It took the best part of a year to finalise the tooling before we were happy,’ he says. ‘Then the search was on for the right German nickel silver and to get the plating perfected.’

The absence of wax-potting in the original PAFs meant guitarists could easily encounter the dreaded ‘squeal’ if they got too close to the amp. Duncan sticks to the original blueprint for his ‘Seth Lover’ model, but now wax-pots many of his other humbuckers. ‘The wax potting removes air pockets inside,’ says Duncan. ‘Air contains oxygen which can cause the pickup to corrode over time.’ Seymour also makes all his own parts. ‘I think that’s one of the things that separates us from the young “kitchen table,” boutique pickup winders,’ states Duncan. ‘Many of them are buying their parts from the big Korean or Chinese guitar parts houses. That’s not our style.’
Apart from the wire and magnets that require a foundry to manufacture, Bare Knuckle also make everything on site. ‘Butyrate humbucker bobbins, nickel silver baseplates, pole shoes, screws, slugs, maple spacers… you name it, we make it,’ enthuses Mills. ‘They’re all accurate to the original PAF design. I think it’s crucial to develop and make your own parts for both consistency and quality of the finished pickup and, most importantly, the sound.’
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