US3472943A - Pickup and circuit for stringed musical instrument - Google Patents

Description

1969 YOSHIKAZU KAWABATA ET AL 3,472,943

PICKUP AND CIRCUITFOR STRINGED MUSICAL INSTRUMENT Filed Oct. 11, 1966 2 Sheets-Sheet l FIG.

FIG. 3 (b) FIG. 3(a) FIG. 5 PRIOR ART Oct. 14, 1969 yos KAWABATA ET AL 3,472,943

PICKUP AND CIRCUIT FOR STRINGED MUSICAL INSTRUMENT Filed Oct. 11, 1966 2 Sheets-$heet 2 n2? 30 FIG. 6

0 LQQ :HHHQHHH H IIIIIIIIIIIIM] 0 United States Patent- Office 3,472,943 Patented Oct. 14, 1969 US. Cl. 841.15 4 Claims ABSTRACT OF THE DISCLOSURE In an electric guitar, a pickup device comprising two electric pickup elements disposed at different positions along guitar strings and each having a pickup coil with two terminals, and two variable resistors with two fixed terminals and a movable terminal, two terminals of each of the coils being connected to two fixed terminals of each of the resistors, one side of one of the coils being grounded, the movable terminal of the resistors connected thereto being connected to the one side of the other of the coils, and the resulting output signal being led out from the movable terminal of the resistor connected to said other of the coils.

This invention relates to electric stringed musical instruments and more particularly to a new and imrpoved pickup device comprising, essentially, two pickup elements and an electrical circuit operating to produce, in a simulated manner, the effect of continuously shifting the positions of the two pickup elements (hereinafter referred to as pickups) which pick up the vibrations of strings in an electric stringed musical instrument without actual mechanical shifting of the pickups.

In an electric stringed musical instrument such as an electric guitar, a requirement arising from the playing thereof is that the tone color be widely variable. To meet this requirement, it has been the conventional practice to provide a plurality of pickups in respectively different positions with respect to the longitudinal direction of each string and to pick up the vibration of the string at these different positions. In known devices for this practice, the range of variation of the tone colors has been limited because of the nature of these devices, which, moreover, have been accompanied by further difiiculty as will be described hereinafter.

It is an object of the present invention to overcome these difficulties by providing, in an electric stringed musical instrument, a pickup device of simple composition and arrangement whereby tone color variation can be accomplished gradually and continuously from hard tones to soft tones and vice versa without mechanical movement of pickups relative to the strings.

More specifically, an object of the invention is to provide a pickup device of the above stated character comprising pickups and a pickup circuit whereby an effect equivalent to the continuous shifting of the positions of the pickups can be obtained electrically without mechanical shifting of the pickups relative to the strings of the musical instrument.

According to the present invention, briefly stated, there is provided, in an electric stringed musical instrument, a pickup device comprising two pickups disposed at respectively different positions with respect to the length-wise direction of the strings of the instrument to receive vibrations thereof and produce respective outputs in response to the vibrations and a pickup circuit connected to the pickups and including one or two variable resistors connected differentially with respect to said respective outputs of said pickups, which are thereby continuously changed over and led out.

The nature, principle, and details of the invention will be more clearly apparent from the following detailed description principally with respect to preferred embodiments of the invention, when read in conjunction with the accompanying drawings, in which like parts are designated by like reference numerals and characters.

In the drawings:

FIG. 1 is a plan view showing the face side of an electric guitar to which one embodiment of the invention has been applied.

FIG. 2 is a diagram, partly in schematic form and partly in structural form, showing the important parts of the pickup system of the guitar shown in FIG. 1;

FIG. 3(a) is a schematic diagram showing an essential part of the pickup system shown in FIG. 2;

FIG. 3(b) is a schematic diagram similar to FIG. 3(a), showing an arrangement wherein the first pickup coil and the second pickup coil shown in FIG. 3(a) are interchanged;

FIGS. 4 and 5 are schematic diagrams showing examples of known pickup devices;

FIG. 6 is a plan view showing the face side of an electric bass guitar to which an embodiment of the invention has been applied;

FIG. 7 is a diagram, partly in schematic form and partly in structural form, showing the important parts of the pickup system of the guitar shown in FIG. 8; and

FIGS. 8 and 9 are schematic diagrams showing the essential parts of further embodiments of the invention.

As conducive to a full appreciation of the novelty and utility of the present invention, the following brief consideration of examples of the prior art is presented.

As shown in FIG. 4 as mentioned briefly hereinbefore, it has been the conventional practice to provide a plurality of pickups 2 and 3 at different positions with respect to each string 1. The outputs of the pickups 2 and 3 are appropriately selected by switches 4 and 5 and led out. Alternatively, for example, as shown in FIG. 5 two pickups 2 and 3 are connected in series, and a variable resistor 6 is inserted as a shunt across one of the pickups, e.g., pickup 3, thereby to vary the tone color by varying the quality factor, Q, of the coil of the pickup 3.

In a device of the above described composition and arrangement, the range of variation of the tone colors is naturally limited. Theoretically, it is possible to vary tone colors over a wide range and, moreover, into many kinds by providing a large number of pickups at respectively different positions. Furthermore, it is possible to obtain continuous or stepless variation by causing each pickup position to shift continuously. Such expedients, however, give rise to extreme complications, which are disadvantageous.

The present invention contemplates the provision of a pickup and circuit device of simple composition and arrangement wherein, by the use of an electrical circuitry, an effect equivalent to continuous shifting of pickups can be obtained without actual mechanical movement of the pickups.

Referring to FIG. 1 illustrating one example of embodiment of the invention, the guitar 20 has a control circuit as shown in FIG. 2 and is connected to the input terminal of a guitar amplifier (not shown) provided separately from the guitar by a cord (also not shown) which is plugged into a jack 30 on the panel 21 of the body of the guitar 20. This example illustrates the application of the invention to an electric guitar in which three electromagnetic pickups are used, and in which strings 11, 12,

13, 14, 15, and 16 are strung in the known manner, being supported on a bridge 31.

One pickup 22 is positioned relatively closely to the bridge 31, while the second pickup 23 is positioned relatively apart from the bridge 31. The third pickup 24 is positioned even farther than pickup 23 from the bridge 31. Each of the pickups 22, 23, and 24 comprises coils of several thousands of turns of winding wound around pole pieces (22A, 22B, 22C, 22D, 22E, and 22F in the case of pickup 22, for example) which are disposed to confront from below, respectively, strings 11 through 16, inclusive.

Since the six strings 11 through 16, inclusive, are made of magnetic material, when each string is caused by the playing of the guitar to vibrate, voltages in accordance with the resulting vibration signal are induced in the pickups 22, 23, and 24.

One terminal of the coil of pickup 24 is grounded, while the other terminal is connected to one fixed contact terminal b of a three-position switch 25. The coils of pickups 22 and 23 are connected to the other fixed contact terminal a of the switch 25 by way of ganged variable resistors 26 by which these coils are mutually coupled, This switch 25 is mounted on the panel 21 of the guitar body and, while the guitar is being played, can be manually switched in a simple manner between three positions, that is, three positions for causing the moving contact me of the switch to contact only the contact a, both contacts a and b, and only the contact b. Thus, by this switching it is possible to select in a simple manner one state from among three connection states, i.e., that wherein only pickup 24 is connected, that wherein only pickups 22 and 23 are connected, and that wherein both pickup 24 and pickups 22 and 23 are simultaneously connected.

The circuit after the switch 25 is of a commonly used type in which there are provided a variable resistor 28 of B type or A type of approximately 500 kilo-ohms, a variable resistor 27 of A type of approximately 500 kilo-ohms, and a 0.01-microfarad capacitor 29 connected to the movable terminal 27A of the variable resistor 27.

Referring to FIG. 3(a) showing the essential parts of the device shown in FIG. 2, the aforementioned ganged variable resistor 26 comprises an A-type, 2S0-kilo-ohm variable resistor 26D and a C-type, 250-kilo-ohm variable resistor 26B, whose respective movable terminals 26C and 26A are adapted to move in an intercoupled manner in the same direction as viewed in FIG. 3(a).

The two terminals of the coil of pickup 23 are connected to the two terminals of the variable resistor 26D, while the two terminals of the coil of pickup 22 are connected to the two terminals of the variable resistor 26B. The side of one terminal 2 of the variable resistor 26D is grounded. The output of pickup 23 is led by way of the movable terminal 260 of the variable resistor 26D to the side of one terminal d of the variable resistor 26B. The outputs of the two pickups 22 and 23 are led out through the movable terminal 26A of the variable resistor 26B.

When the movable terminals 26A and 26C of the ganged variable resistors 26 are moved to the side of terminals d and f, the output from pickup 23 is obtainable, and when these movable terminals 26A and 26C are moved to the side of terminals c and e, the output from pickup 22 is obtainable. At an intermediate position between terminals c and d terminals e and 7, an output mixture of the outputs of both pickups is obtainable, the proportions of the outputs in the mixture being in accordance with the intermediate position.

This ganged variable resistor 26 is installed in the body of the guitar and can be operated in a simple manner by a control knob 26N mounted on the panel 21 as shown in FIG. 1. Accordingly, even during playing of the guitar, an effect equivalent to an apparent movement of the positions of the pickups can be obtained in a simple manner.

In another embodiment of the invention as shown in FIG. 3(b), the positions of pickups 22a and 23a are reversed relative to those of pickups 22 and 23 in the arrangement illustrated in FIG. 3(a) in respect to the relative distances of the two pickups from the bridge 31. In other words, interchanging of the positions of the pickups 22 and 23 together with their respective associated parts of the ganged variable resistor 26 in the arrangement of FIG. 3(a) results in the arrangement of FIG. 3(b). In other respects, the two examples are alike, and the above description set forth with reference to FIG. 3(a) is applicable also to the example shown in FIG. 3(b).

FIG. 6 shows a bass guitar to which an example of the invention of improved form is applied. This guitar is a four-string instrument in which two pickups 122 and 123 are used, and which is approximately equivalent to the guitar shown in FIG. 1 from which pickup 24 shown in FIGS. 1 and 2 has been removed. While this embodiment of the invention will be described with respect to its application to a bass guitar, it will be obvious that this embodiment can be applied also to an electric guitar as shown in FIG. 1.

This example shown in FIGS. 6 and 7 incorporates improvements for the case where, in embodying the circuit of FIG. 3, relatively large numbers of winding turns of the pickup coils are required, that is, the case where the stray capacitances of the pickups and the resistance components at the intermediate positions of the movable terminals 26A and 26C of the variable resistors 26 constitute low-pass filters whereby the high-frequency components of the signals are attenuated.

The essential parts according to the invention of the guitar shown in FIG. 6 are shown in FIG. 7. The essential parts and their arrangement shown are the same as those shown in FIG. 3 except for the provision of capacitors 132 and 133. The capacitor 132 is connected between the side 0 of the coil of pickup 122 and the movable terminal 126A of variable resistor 126B, while the capacitor 133 is connected between the side 7 of the coil of pickup 123 and the movable terminal 1260 of variable resistor 126D. The electrostatic capacitances of these capacitors are each 0.003 microfarad in the example shown.

When, with the capacitors 132 and 133 connected in this manner, the variable resistors are moved, and their movable terminals 126A and 126C are respectively placed at the terminals 0 and e, the pickup 122 is not aifected by capacitor 132. On the other hand, when these movable terminals are respectively placed at terminals d and f, the pickup 123 is unaffected by capacitor 133. Thus, at these terminal positions of the movable terminals 126A and 126C, signal voltages induced by the vibration of each string can be led out with the pickups in their respective unaffected states.

However, when the movable terminals of the ganged variable resistors 126 are in intermediate positions between terminals c and d and terminals e and f, the capacitors 132 and 133 are placed into effective states. As a result of the addition of these capacitors 132 and 133, the respective high-frequency components of the signal voltages of pickups 122 and 123 are not attenuated and fully appear on the output side even when the ganged variable resistor is in an intermediate position. The resulting reproduced sounds, supplemented by the high-frequency components, become brilliant and strong sounds.

In a further embodiment of the invention as shown in FIG. 8, a plurality of fixed resistors 36A and 36B and intercoupled-type selector switches 35A and 35B are used in place of the ganged variable resistors of the example illustrated in FIG. 3a. In this pickup system, it is not possible to obtain continuous or stepless variations of tone color as are obtainable by the use of a ganged variable resistor as illustrated in FIG. 3(a), but a plurality of suitable combinations of tone colors can be selectively prepared beforehand and, during playing, selected in a simple manner.

More specifically, when the selector switches 35A and 35B are switched to the taps designated by v and w on the side, output from pickup 22 is obtainable, and when these switches are switched to taps x and y on the other side, output from pickup 23 is obtainable. At intermediate, taps, a mixture of the outputs of the two pickups 22 and 23 in proportions corresponding to the tap position is obtainable. Accordingly, by operating the intercoupled changeover switches 35A and 35B, it is possible to obtain the same effect as that obtainable by the use of a large number of pickups.

Furthermore, a modification as illustrated in FIG. 8 can be produced by adding capacitors as described hereinbefore with reference to FIG. 7 to the circuit shown in FIG. 8.

As described above, the present invention provides, in an electric stringed musical instrument, a novel pickup device of simple circuit composition and arrangement whereby tone color variation can be accomplished gradually and, moreover, continuously from hard tones to soft tones and, conversely, from soft tones to hard tones without mechanical movement of the pickup elements relative to the strings. Thus, by the practice of the invention, it is possible to obtain an effect, unattainable heretofore, which is equivalent to that produced by mechanical movement of the positions of the pickup elements relative to the strings.

It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

What we claim is:

1. In an electric stringed musical instrument, a pickup device comprising two pickup elements disposed at respectively different positions with respect to the lengthwise direction of the strings of the instrument to receive vibrations thereof and produce respective outputs in response to said vibration, and a pickup circuit connected to the pickup elements and including at least one variable resistor connected differentially with respect to said respective outputs of said pickup elements whereby said respective outputs are continuously changed over and led out, each pickup element having a pickup coil with two terminals connected respectively to the fixed terminals of a respective one of two mutually intercoupled variable resistors, the negative side of one of the pickup coils be ing grounded, the movable terminal of the variable resistor connected thereto being connected to the negative side of the other pickup coil, the resulting output being led out from the movable terminal of the variable resistor connected to said other pickup coil.

2. The pickup device as claimed in claim 1, in which a capacitor is connected between the signal lead-out side of each pickup coil and the movable terminal of each of the two variable resistors.

3. The pickup device as claimed in claim 1, which each variable resistor comprises a plurality of fixed resistors between the fixed terminals thereof and a selector switch having a movable terminal and a plurality of fixed terminals connected to respective junction terminals of the fixed resistors whereby the resulting output is led out.

4. The pickup device as claimed in claim 3, in which a capacitor is connected between the signal lead-out side of each pickup coil and the movable terminal of the corresponding selector switch.

References Cited UNITED STATES PATENTS 2,784,631 3/1957 Fender 841.16 3,194,870 7/1965 Tondreau et a1. 841.16 3,291,888 12/1966 Meazzi et a1. 841.16

HERMAN KARL SAALBACH, Primary Examiner PAUL L. GENSLER, Assistant Examiner US. Cl. X.R.

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