Wiring All-Humbucking Single-Coil Pickups

One member of reddit-r-guitar asked a question that needs an answer.  Is the patent-pending system of all-humbucking matched single-coil pickups easy to wire, and is it intuitive to use?

In answer, here below are excerpts from Patent Application US 2016/0027422 A1, also on Google Patents, with Figures showing the wiring.  The 4P6T rotary switches to use with Fig. 24 are cheap and common. A 4P5T guitar “superswitch” can be used to wire up 5/6 of Fig. 24, leaving off any one combination.

The 6P6T or 6P12T switches required for Figures 25 and 26 are not commonly cheap and available.  They are likely to be expensive custom switches that might even be too large to fit inside a regular guitar.  I had a partial solution in the 4th prototype, with four single-coil pickups, which used two 5-way 4P5T guitar superswitches, one for parallel connections and one for serial connections, with a 4PDT input switch selecting between them (Patent Application Figs. 27-29).  With only 4 poles per superswitch, this tends to leave out any counter-phase connections.  The setup allowed for 4 in-phase humbucking pairs and one in-phase humbucking quad (which ended up sounding a lot like an acoustic guitar).

The switching diagrams in the figures are all set up to go from warm on the left to bright on the right.  Be warned that before wiring anything, it’s best to draw up a physical wiring diagram showing the actual switch soldering lugs, and wire connection between them, triple- and quadruple-checked.

Please be reminded that while you can wire up your own personal guitar this way, yourself, without sanction, it is not legal under U.S. patent law for you either to sell either your services to wire pickups this way, or to make for profit or sell guitars wired this way, unless you are licensed to do so. Click here for contact information.

Here are the excerpts:

Figs. 23-31 describe improvements to the pickup switching system

[0129] Fig. 23A shows the basic parallel coil humbucking circuit, for either two single-coil pickups, or a dual-coil humbucker. Fig. 23B shows a series connected circuit. Humbucking refers to the ability of the circuit to cancel out external varying magnetic fields that do not arise from the interaction of the strings and the pickup. This drawing presents a single-coil pickup in the simplest possible terms: a magnet (293), a coil of wire (295, usually around or above it), and a lead designated “+” (299) which has the same phase of signal as all the other pickups in the circuit with “+” leads. Standard symbols for the signal output (301) and ground (303) are shown.

[0130] Say there are two pickups, one with its north pole (293) next to the strings (or upwards), and the other with the south pole (297) next to the strings. If the coils are  wound in the same direction, say CCW in the top view (or left-handed), and are near each other with respect to the vibrations of the string, then the vibrations will produce signals of opposite phase in the same respective leads on each coil, because the magnetic poles are reversed. The leads of one coil must be reversed to keep from canceling out the string signal. But this will cause an external signal, like 60 cycle machinery and light signals, which has nothing to do with the pole orientation, to cancel. Thus “humbucking”. It is convenient not to show crossed leads for one coil, but to simply assign the in-phase lead to the top and label it “+”.

[0131] In order for this to work, both coils have to have the same number of effective turns, which can be influenced by an artificial and/or intended concentration of the external field in the instrument. In general, most replacement pickups will have to be wound to match the pickup in the set with the highest signal output of external fields. Also the series circuit tends to have a stronger signal with less high frequencies (warmer), and the parallel circuit tends to have a weaker signal with a peak in higher frequencies (brighter).

2016-0027422-Fig 23A-B

[0132] Fig. 23C shows a switched circuit, using a double-pole double-throw (DPDT) switch (305) to produce series and parallel outputs, like 23A and 23B. Rather than having switch arrows that rotate to a number of positions (throws), this diagram uses slightly nonstandard symbolism, which puts the poles on the right and the switch positions for “throws” successively to the left. It makes the circuits a lot easier to draw and understand. Note that the + wire of the north-up pickup is connected permanently to the output and the other wire of the south-up pickup is connected permanently to the ground, which makes humbucking circuits easier to draw, with a minimum number of switch poles. So switch position 1 (POS 1) is made series merely by connecting the two switch terminals together, and position 2 (POS 2) is made parallel by the N-up coil switch terminal to the ground and the S-up terminal to the output.

[0133] Fig. 23D shows how two N-up single coils are connected in series and parallel circuits. Here, the N-up pickup from 23C is moved down and replaced with another N-up pickup with the “+” wire connected to ground. Because the pickups are both N-up, both the external and string signals tend to cancel each other. But the string signals will still be stronger because of the presence of higher harmonics of the fundamental frequencies of vibrations, which this circuit tends to emphasize.

2016-0027422-fig 23C-D

[0134] Fig. 24 shows how three pickups can be connected into six humbucking pairs with a 4P6T switch (313), using the previous switching symbolism. The neck position pickup (307) and bridge pickup (311) are N-up, with the middle pickup (309) S-up. The number of possible pickup combinations of one type, series or parallel, of three pickups taken combined in pairs is (3*2)/(2*1) or 3, making 6 total for both series and parallel. This includes the opposing signal (out-of-phase) pairings of the two N-up pickups. Here the symbolism at the switch positions for the connections uses “+” for series (315), “||” for parallel (317), and “-” for an opposing signal (319). This makes the circuit diagram easy to read and understand at a glance. Note that for a commercially available 5-way guitar “superswitch”, which is 4P5T, one of the combinations must be left off (likely -N||B).

2016-0027422-Fig 24

[0135] Fig. 25 shows a 6P6T switching circuit for two N-up pickups at the neck (307) and bridge (311), with two S-up pickups in between in the Middle 1 (321) and Middle 2 (323) positions. Here four pickups taken two at a time in series produces (4*3)/(2*1) different pairs, or 6.

2016-0027422-Fig 25

Fig. 26 shows the corresponding 6P6T switching circuit for parallel connections. Both figures together produce 12 combinations of humbucking pairs. The least number of switch poles necessary for the circuit to work depends on the number of magnetic poles up. If all K pickups have the same polarity of poles up, then a switch with switch with 2*K-1 poles is needed, and only one pickup can have a permanently connected wire, with the other served by a single pole. If at least one pickup has a different polarity, then a switch with 2*K-2 poles is needed, and a single pickup of each polarity up can have permanently connected wires and be served by single switch poles.

2016-0027422-Fig 26