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P90-Bucker story

The story of the P90-Bucker

The story of the Kinman P90-Bucker begins where Seth Lover left off in 1955.

Hello everyone, I thought some of you will be interested in following the development of a radically different humbucker I call the P90-Bucker. As the same implies it’s got the sound of a P-90 in a humbucker format, which means it also has Zero-Hum like all Kinman pickups.

Some of you might already know that back in 1955 Seth Lover was instructed by Gibson president Ted McCarty to solve the hum problem of the P-90. Obviously I take that to mean to keep the sound of a P-90 but get rid of the hum. Well, Seth certainly solved the hum problem but his humbucker sounds nothing like a P-90. Gone was the snappy attack (thwack), high definition and piano tones of the low wound strings and wonderful dynamic range. A P-90 it most certainly is not.

When I undertook to develop a Humbucker that fulfilled Seth Lovers brief back in 1955 I had no idea of what surprises/shocks were in store for me. I had a hunch it was possible to get a P-90-ish sound from a side-by-side humbucker because there is a strong resemblance between the two pickups since both have same coil height, both have same steel poles and same bar magnet, both have a total of 10,000 turns of 42 gauge wire. But now I know the reason Seth Lover, a capable engineer, couldn’t do it.

My first attempt was the Clean Skin model I introduced late 2011. I had to think well outside the box for that humbucker and I was able to get 85% of a P-90 sound. But it became pretty clear my customers expected more than 85%, you want 100%. So over the last 2 years I have given a lot of though to the problems of humbuckers. I studied various humbuckers (other than Kinman already improved humbuckers of course) to see if any sounded better then a regular Gibson PAF style. The Gretsch Filtertron from all accounts has a twangy sound but when I played one I immediately heard the low E and A string sounded muffled and very indistinct. Only the middle strings had any kind of focus and twang, and even then it wasn’t quality twang but more the product of upper midrange spikes that are the precursors to Ice Pick. I wondered if the pickups I tested were somehow faulty but on every sound clip I heard the same thing, and then I read on some forums players complaining about the same thing.

Gibson PAF style humbuckers have the same problem although not quite as bad as the Filtertrons. One very accurate forum post described humbuckers as being paradoxically too bright (plain strings) and too dark (low wound strings) at the same time, a view that is close to home for me too as I have done a lot of work to overcome just that. Coupled with my own Research, Experimentation and Development activities I came to realize that the conventional side-by-side humbucker design succumbs to the Laws of Electrical Physics, and that size does matter, a LOT!

As it turns out Gretsch Filtertrons, Mini-Humbuckers and Gibson style regular humbuckers (and clones thereof) suffer from having coils that are not big enough. The Filtertron has even smaller coils than the Gibson bucker. It really is so very interesting that humbuckers became the most popular pickup in spite of this obvious flaw.

The whole Size-Does-Matter thing first became evident when Seth Lover divided the P-90 into 2 equal (smaller) halves back in 1955 and created his twin coil humbucker out of it. What he did, by design or by accident, was to cut an important electrical performance commodity of the P-90 coil in half too. Some electrical factors do not add together, as resistance does when coils are connected in series, so that very important commodity was not recoveredit was completely lost. And then there is my discovery of an obscure or even unknown Law of Electrical Physics that only operates in the side-by-side configuration of Humbucker coils.

Seth realized this himself when he designed Fenders Wide Range humbucker, so he went outwards and the WR is much wider and longer than a Gibson style bucker. But he also did some other curious things that help negate the gains he might have realized with wider coils. I wanted a replacement humbucker which means the footprint must be no bigger than a regular humbucker of the Gibson (and clones) type.

So my question became ‘what can be done to overcome these problems? And ‘what wire gauge should be used?’ These are question that never arose with Seth Lover because, as he stated in his 1978 interview with Seymour Duncan, to save time and cost of materials he simply used what he had on hand and that was 42gauge plain enamel wire and P-90 bobbins. Seth simply filled the cut-down P-90 bobbins with 5000 turns of 42 gauge wire he had on hand, which is half of the 10,000 turns of a P-90. I understood the shortcomings of that simple approach and so made it my mission to experiment with coils and different wire gauges and push on the boundaries. To find the answers to my questions I embarked on constructing a series of experimental pickups. I made about 8 of these things and that took some time to do let me tell you. I spent many hours laboriously making the special pole pieces on my lathe and milling machine. Trying different windings and observing the result and looking for a pattern. The first 8 pickups were failures and even though I had made the coils significantly taller than a conventional humbucker the same old dull low E & A strings persisted. There was no pattern of improvement emerging here. Even though I had also tried lots of different wire gauges I was beginning to think the whole side-by-side coil thing was fatally flawed and a waste of time. Try as I might I just couldn’t get enough brightness & attack into the sound equally on all strings. Still I persisted because I know the laws of Physics and Electricity and I knew that somewhere there was an answer that would allow the side-by-side humbucker to sound like Gibson meant it to sound, like a P-90. So I constructed a few more pickups with even bigger coils. Still the goal eluded me. This was turning out to be a tough R&D project, almost as tough as silencing single coil pickups without destroying the original sound. But I shouldn’t be comparing because that took me 16 to 20 years to really get on top of.

Feeling utterly frustrated I began looking at cunning ways that were way outside the box of convention, one of these ideas was to increase the magnetic efficiency of the coils which would allow me to use bigger wire and so simultaneously maximize and minimize various electrical parameters governing the production of attack and piano tones of the low E & A wound strings. I already made that work to my advantage with my P-90 Hx after fully exploring conventional technology failed to provide the solution. As many of you know the Kinman P-90 Hx with it’s 206 components is still the only authentic P-90 sounding hum-canceling pickup in existence, all others are just P-90 look-alikes. Apologies if the truth offends.

So I began to apply what I learnt with the P-90 Hx, but still the answers didn’t come forth, not even a hint that I was on the right path. Still I pressed on knowing there had to be a solution, somewhere … somehow. I was right, experimental pickup number 23 suddenly turned on the light. Finally I could hear piano tones on the low wound strings, and there was some sharper attack too. But it wasn’t quite there and a lot of thinking remained to be done.

At 3:15am one morning I sat bolt upright in bed as my subconscious found the solution. It was a cunning idea that I had not seen elsewhere and I felt it would solve the problem. I am not going to divulge what the idea was but I can tell you that, with some corrective design, that idea did indeed provide the solution that was the last piece of the jig-saw. Finally all the pieces fell into place with experimental pickup number 28 and the total picture (the original goal) looks similar to a conventional humbucker BUT sounds like a P-90. And of course a Zero-Hum P-90 sound at that.

My EUREKA moment had finally arrived.

The P90-Bucker, at last, delivers the 100% so many of you asked for, and that is what Gibson President Ted McCarty asked Seth Lover to do way back in 1955. It has very different innards, and new technology but amazingly has DC resistance of 8.7K, a very respectable inductance of 7.8 Henrys and a proud Q factor of 4.

In the right hands Science can do wondrous things for mankind.

So where did Seth go wrong? It is pretty obvious that he didn’t spend enough time and try different things. He was too glued to the architecture of the P-90 and when that didn’t work as hoped for he wrongly assumed that the act of splitting a P-90 into 2 coils was responsible. With that false assumption he was fated to accepting his design as the best a humbucker could be. Actually there is one more aspect to this, the technology that is key to the solution would not be invented until 2009 and that Technology was invented by your’s truly. Seth didn’t do as well as he might have but he can certainly be forgiven for not achieving the goal of authentic P-90 sound.

So if you have a Les Paul, SG, PRS, Archtop, Stratocaster, Telecaster or any other guitars equipped with humbuckers and you are sick n tired of muddy, indistinct low E and A strings and want to hear the actual sound of your strings (i.e. some gorgeous piano tones) delivered with some nice thwack attack, with Zero-Hum, you now have the solution. It’s one hell of a humbucker ….. the P90-Bucker delivers!!! www.kinman.com

Albert Einstein's most profound discovery: If you always do what you always did you'll always get what you always got. It means think outside the box and do something different. I had to think way outside the boundaries of conventional thinking to solve the problems with the humbucker and come up with the P90-Bucker.

Chris Kinman