New page with U.S. Patents for licensing

The following U.S. Patents are available for licensing. Click Here for the index page, and click on the links below to reach each patent. They have all been modified upgraded from the standard download to include drawings and properly formatted equations and tables.

U.S. 9,401,134, Baker, 2016 – Acoustic-electric stringed instrument with improved body, electric pickup placement, pickup switching and electronic circuit

Abstract – An electric-acoustic stringed instrument has a removable, adjustable and acoustic artwork top with a decorative bridge and tailpiece; a mounting system for electric string vibration pickups that allows five degrees of freedom in placement and orientation of each pickup anyplace between the neck and bridge; a pickup switching system that provides K*(K-1)/2 series-connected and K*(K-1)/2 parallel-connected humbucking circuits for K matched single-coil pickups; and an on-board preamplifier and distortion circuit, running for over 100 hours on two AA cells, that provides control over second-and third-harmonic distortion. The switched pickups, and up to M=12 switched tone capacitors provide up to M*K*(K-1) tonal options, plus a linear combination of linear, near second-harmonic and near-third harmonic signals, preamp settings, and possible additional vibration sensors in or on the acoustic top.

U.S. 10,217,450, Baker, 2019 – Humbucking switching arrangements and methods for stringed instrument pickups

Abstract – This invention develops the math and topology necessary to determine the potential number of tonally distinct connections of sensors, musical vibration sensors in particular. It claims the methods and sensor topological circuit combinations, including phase reversals from inverting sensor connections, up to any arbitrary number of sensors, excepting those already patented or in use. It distinguishes which of those sensor topological circuit combinations are humbucking for electromagnetic pickups. It presents a micro-controller system driving a crosspoint switch, with a simplified human interface, which allows a shift from bright to warm tones and back, particularly for humbucking outputs, without the user needing to know which pickups are used in what combinations. It suggests the limits of mechanical switches and develops a pickup switching system for dual-coil humbucking pickups.

U.S. 10,380,986, Baker, 2019 – Means and methods for switching odd and even numbers of matched pickups to produce all humbucking tones

Abstract – This invention discloses a switching system for any odd or even number of two or more matched vibrations sensors, such that all possible circuits of such sensors that can be produced by the system are humbucking, rejecting external interferences signals. The sensors must be matched, especially with respect to response to external hum and internal impedance, and be capable of being made or arranged so that the responses of individual sensors to vibration can be inverted, compared to another matched sensor, placed in the same physical position, while the interference signal is not. Such that for 2, 3, 4, 5, 6, 7 and 8 sensors, there exist 1, 6, 25, 90, 301, 966 and 3025 unique humbucking circuits, respectively, with signal outputs that can be either single-ended or differential. Embodiments of switching systems include electro-mechanical switches, programmable switches, solid-state digital-analog switches, and micro-controller driven solid state switches using time-series to spectral-series transforms to pick the order of tones from bright to warm and back.

U.S. 10,810,987, Baker, 2020 – More embodiments for common-point pickup circuits in musical instruments

Abstract – This invention refines and expands the use of mode switches in common-point connection circuits for matched pickups on musical instruments. For example, on a 3-coil S-type electric guitar, where the common-point connection circuit with a single-ended output provides three humbucking pair outputs and three humbucking triple outputs, a 4P2T mode switch can ground the common point and provide both all of the standard non-humbucking 5-way switch outputs, as well as adjusting the tone capacitor to make both humbucking and non-humbucking tone outputs more compatible. On an electric guitar with three dual-coil humbuckers, mode switches of one 6P2T, one 2P2T and three 1P2T can choose between dual-coil and single-coil operation modes, humbucking and non-humbucking modes, and partially simulate the effect of flipping single-coil magnets at will, by choosing which coil of each humbucker is used.

U.S. 10,847,131, Baker, 2020 – Modifications to a lipstick-style pickup housing and core to allow signal phase reversals in humbucking circuits

Abstract – This invention discloses a pickup based upon the core of a common lipstick pickup for an electric stringed musical instrument with a core and housing, the core comprised of a magnet, coil form, and a wire coil connected to electrical contacts on the coil form, and a separate housing providing mounting to the body of the instrument and mating electrical contacts for that core, such that the core can be removed from the housing, flipped so as to reverse the magnetic field towards the strings, and reinserted into the housing, such that any humbucking circuit constructed with other matching pickups will remain humbucking.

U.S. 10,878,785, Baker, 2020 – Stringed instrument pick holder with adaptation to pick guard

Abstract – This invention uses a simple, decorative and effective way to hold picks to a guitar body, especially a solid electric guitar body or the head of a neck. It comprises a flat plate, which can be conveniently included in the design of a pick guard, using at least one mounting screw, one or more fingers to hold down individual picks, each tensioned by separate screw, and a thin shield under the pick holder to keep each pick from rubbing on the body finish. The parts can be cut, carved or printed to decorative designs.

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Eulogy for Adobe PhotoShop 7 ™

Thanks to Microsoft, most likely, PS7 is getting Alzheimer’s. It no longer remembers to stroke the entire path on command, leaving sections undone. Why? Probably because I used Windows Update on Windows 7.

I recently upgraded my connection from a mobile hotspot to cable internet, so that the Windows updates wouldn’t kill off my $10/GB metered data. After hundreds of megabytes of updates, my Windows 10 laptop now boots and comes out of hibernation slower than ever, and PhotoShop 7 on my Windows 7 desktop is losing capability.

I shall mourn PhotoShop 7. Its classic toolset is so perfectly made that I’ve learned to use it for photos, paintings, graphic art, CAD drawings and electronic circuit diagrams ever since it was Version 4. For example, I used it to take a pencil drawing like this:

(c) Don Baker 2010

and turn it into this:

(c) Don Baker circa 2011-12

I used it for all the figures of guitar bodies, electronic circuits and graphs in U.S. Patent 9401134 B2:

Until now, I have not needed anything else. I’m currently using it for patent applications and to write a new textbook on guitar electronics. That has now become more difficult and uncertain.

Microsoft is like a Developer enthusiastically putting up ever-higher and more expensive condos, without bothering to notice the endangered flowers and butterflies it tramples underneath. Never bothering to fix the old bugs as it compulsively adds every more bloated “features”. Creating millions upon millions of lines of octopus-code, all the while installing new bugs. It doesn’t really care how much it damages the work of others, so long as it can induce us to buy more products. Whether we can afford them or not.

If Karma accrues, sooner or later, these turkeys will have to live on Social Security and minuscule COLAs, while their medical insurance continues to rise above that pace. One can only hope.

© 2018 Don Baker dba android originals LC, Ph.D retired

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New U.S. Patent filed & background published

Yesterday, I filed my 3rd Non-Provisional Patent Application, and today published the background theory for it at:   The patent involves matched, single-coil pickups for humbucking circuits with reversible magnetic poles.

I have a new area for publications of papers like this on ResearchGate.Net.  There are 2 so far.  You can find them at:


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Banning Users

The majority of new users who sign up turn out to be listed as spammers on  From now on, those new users will not only be deleted, their domains will be banned.  Why do they even bother?

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On the Topologies of Guitar Pickup Circuits

How do you get 620 potentially unique guitar tones from 4 single-coil pickups, or 310 from 3 humbuckers?

Read here:

Abstract: Many of the U.S. patents involving switching circuits for electric guitar pickups have failed in the marketplace because they do not show the topologies generated by switching configuration, and thus fail to eliminate duplicate circuits and circuits with null outputs. Series-parallel circuit topologies of any complexity, with potentially unique tones, can be generated from small to complex by simple rules, as can the number of ways to switch pickups around in a particular topology, and to reverse individual pickup connections to change the phase of their contribution to the output. But the audio separation of “potentially unique” tones have to be verified by spectral measurements. This affects both single-coil and dual-coil humbucking electromagnetic string vibrations pickups, as well as other types of sensors.

This is just the beginning

(c) 2018 Don Baker  dba  android originals LC

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The Walkin Squawkin Patent Examiner Blues – Part 1

I got this in an e-mail from my U.S. Patent Office Patent Examiner on Jan 24th, 2018:

“I cannot conceive of any way to generate an “infinite” (your word) table that would accommodate the breadth of claim 28. You mentioned going through this and “visually” deleting duplicates. How do you do that with infinite pickups? How do you do it with 500,00 pickups? 10,000? 500? You mention FFT, claim 28 is silent as to any FFT. Or, how do you create a table-lookup system to delete duplicates of, say, 500,000,000 pickups? 10,000? 500? Even 25? And finally, to me, removing duplicates is pretty obvious, e.g., to optimize user experience, to reduce CPU load, minimize memory/storage, etc. I just did a quick search of “eliminate duplicates” and returned about 14,000 hits.”

Speaking of “obvious”, I got this from Google today:

Can you say “super obvious”?

There’s a mathematical object, with which some Patent Examiners may not be familiar, called an “infinite series”. It doesn’t mean that you have to take it all the way to infinity, just that in principle it can be taken that far, according to some relatively simple rule.

I have a relatively simple set of rules for expanding pickup (and other sensor) circuit topologies from a single pickup, to a series and parallel pair, up to any number and complexity of series-parallel circuits you might wish. To cover all the cases, these rules happen to generate a number of duplicate circuit topologies that have to be eliminated, before counting up how many different ways you can get potentially unique tones from those pickup circuits. For small number, you just look at them and ask, “Which one of these is like one of the others?”

Simple, but most inventors who have filed pickup circuit patents haven’t bothered even to draw out the circuits their switching systems produce. Consequently, their patented switching circuits often have a number of duplicate circuits, producing duplicate tones. And even a number of circuits producing no output at all.

This goes all the way back to the Fender Marauder patent, US3290424, C.L. Fender, 1966. Four 3-throw switches gave it 81 different parallel-circuit switch configurations, of which one had no output. About half of the rest are duplicate circuits with duplicate tones, simple because of you reverse the output connections of a pickup circuit, the human ear cannot tell difference without any other reference. And of the unique tones, only a small fraction could have been humbucking.

The Marauder allegedly failed in the marketplace for being too noisy. Not to mention 81 switch positions with no map to the tones and duplicate tones.

So I systematically went about determining just how many unique series-parallel connections you could get from J number of pickups, how many unique ways you could switch pickups from one spot in the circuit to another, and how many unique ways you could reverse the connections of one or more pickups in the circuit to get a new tone. The number of unique topologies for J pickups don’t seem to have an equation, but number of ways you can switch pickup positions and reverse connections do.

So, how do you figure this out for “500,000 pickups?” Can you say “computer”?

Claiming, “I cannot conceive of any way to generate”, is like saying that because it is difficult to add 3000 10-digit numbers, that one must throw out the principles and methods to add 2 4-digit numbers. And besides that, the claim involving FFTs was past where this gentleman had bothered to read, in the second independent claim set.

And last, but not least, no matter how many unique circuits and tones you may devise, they are not truly unique until they are proven unique with actual spectral measurements. Because as the Great Murphy can tell you from his Law, if two tones can be very close together as to be virtually indistinguishable, they will be. You just don’t know which ones or how many. And that children, is why we say “potentially unique”.

It seems than an engineer has much less problem with this fact of nature and life than at least one U.S. Patent Examiner.

(c) 2018 Don Baker   dba   android originals LC

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Why guitar pickup switching patents fail in the marketplace

I’ve reviewed some more guitar pickups switching patents lately, and most if not all of the ones I’ve seen suffer design flaws that generally cause them to fail in the marketplace, for some of the following reasons:

  1. They almost never show in the Figures all the circuit topologies that the switching configurations produce, and thus never discover all the duplicate circuits and circuits with null outputs. This often leaves the user with a lot of switch combinations that produce exactly the same tones, or no tones at all.
  2. They don’t acknowledge that the human ear cannot tell the difference between a signal and its inverse phase, without a separate reference. Thus the signals like N B and –N+B are often wrongfully counted as separate tones.
  3. They don’t acknowledge that the coils of humbuckers are so physically close together (about the 16th to 32nd harmonic) that, even if they produced separate signals, they produce virtually the same signal. Never mind that they share the same magnetic circuit and are magnetically coupled, like an audio transformer. I have even used a HB with a signal generator as an audio transformer to test a preamp circuit. Not very efficient, but it produced a signal. So often every combination of one coil each from 2 humbuckers is wrongly counted as a separate tone, ignoring duplicates. Not counting any series and parallel combinations, 2 humbuckers produce exactly 2 single-coil tones (N and B), 2 humbucker tones (NN and BB), and two 4-coil tones, (NN+BB and NN-BB). Out-of-phase combinations in the same humbucker, like Nn-Ns or Bn-Bs, where n and s are the north-up and south-up coils of the humbuckers, produce virtually null signals.
  4. They don’t acknowledge that the only tonal difference between a series and parallel combination of two pickups or coils comes from the interaction with the load, namely the tone pot circuit and the volume pot, and the guitar cable and amp input. A lower impedance load causes the higher-frequency tones to roll off at a lower frequency than a higher impedance load. So when a pickup or coil feeds directly into a preamp that has a fixed impedance, there is no difference in tone unless the series-parallel switching is done before the preamp. And if the preamp has a very high-impedance input, then tonal difference between series and parallel pickup coils switched before the preamp will be well above human hearing.
  5. They don’t verify, by any kind of spectral measurement, that all the switch combinations actually produce audibly separate tones. They often falsely assume, without measurement and verification, that every different switch combination must produce a different tone, the more the better. Then, without ever having mapped what tones go with what switch combinations, they leave it all to the user to figure out. Then, to all that complexity producing such small results, they add the cost of more electronic parts.
  6. And has anybody seen a guitar with digital signal processing sweep the market?

Small wonder that the 3-way and 5-way switches are still so popular, and make up the bulk of the market, even if they are 50 years or more old.

© 2018 Don Baker dba android originals LC, Ph.D retired

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Coming Patents for 2018-2019

From simple principles of circuit theory, a patent currently in examination (a Non-Provisional Patent Application, or NPPA) develops and enumerates all possible combinations of pickup circuits, from 1 to infinity, which have potentially unique tones. It claims all such circuits which are not already patented or currently in use. By replacing single pickups with humbucking pairs, it develops, enumerates and claims all humbucking pickup circuits (not already patented or currently in use) with potentially unique tones, made up of humbucking pairs, quads, hexes and up to infinity.

It demonstrates and claims methods for determining what kind of pickup connection reversals can produce potentially unique humbucking tones. It develops and claims a humbucking triple, demonstrating a principle that applies to all other such circuits with odd numbers of pickups. It develops and claims methods for identifying tones as bright or warm and the order of them from bright to warm. It claims a micro-controller pickup switching system which uses those principles to map tones in order from bright to warm, and provide a simplified user interface, to shift smoothly from bright to warm. With this digital controller approach, no more shotgun switching circuits, leaving it to the guitarists to figure out where the tones are, and which ones are noisy.

Recently filed Provisional Patent Applications (PPA, or patent pending), which will become NPPAs, develop, enumerate and claim:

  1. Humbucking circuits with odd numbers of pickups, from 3 to infinity, with potentially unique tones.

  2. From the preceding work, identifying humbucking circuits with potentially unique tones, for any number of pickups from 2 to infinity, a system for producing humbucking tones from active pickups using vector math and variable gains. The number of potentially unique tones is reduced, because active pickups no longer have different tones when connected in series and parallel. But all of the remaining tones for any number of pickups, odd or even, are produced, plus all those continuously variable tones in between. This mostly eliminates electro-mechanical pickup switching, replacing it with potentiometer controls.

  3. A micro-controller system with a simple user interface for the control of variable pickup gains, and the ordering of tones from bright to warm. It’s possible to use electro-mechanical pickup switching, but beyond 2 humbuckers or 3 single-coil pickups, the number of possible unique tones overwhelms what mechanical switches can do. And generally, mechanical switches do not lend themselves well to switching smoothly from bright to warm. The tonal transitions in mechanical switching tend to jump back and forth from brighter to warmer in a manner that challenges intuition.

  4. Modifications to analog and digital pots to provide variable gain control that evenly spreads the tones over the ranges of the pots, and to control K number of pickups with K-2 number of pots. That’s right, one control for all the continuous humbucking tones of a 3-coil guitar, from in-phase to out-of-phase. A modification also works for dual-humbuckers.

So far, these improvements are theoretical. But the math works and I trust it. It comes from tools I learned back in the 1960s as an electronics engineering student at the Massachusetts Institute of Technology, as well as later signals analysis courses in grad school. See

Although the signal path can contain active, amplifying circuits, it is still purely analog. It does not get between the magic of the fingers and the strings, as does digital signal processing. Any digital micro-controller circuits are used only for simplifying the user interface, to measure the brightness of each switched or continuous tone, to provide a simple tone-shift control, and to drive any digital pots in the circuits.

© 2017 Don Baker dba android originals LC, Ph.D retired

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