Patent Grant
8940993
This application is based on Provisional Application 61/859,845, filed 30 Jul. 2013, the disclosure of which is expressly incorporated herein by reference in its entirety.
This disclosure directs itself to a variable tone configuration control for string instruments that permits switching between series and parallel configurations of pairs of electromagnetic pick-up coils and intermediate variations thereof. More in particular, the disclosure is directed to a variable tone configuration control for string instruments that includes a pair of pickup coils disposed on a string instrument for inducing voltages therein responsive to vibration of at least one string of the string instrument and the pair of potentiometers are coupled to a pair of output terminals and the displaceable contact of each of the potentiometers is electrically connected to a respective one of the pair of pickup coils for selective operative coupling of the pair of pickup coils coupled in series to the output terminals, or the pair of pickup coils coupled in parallel to the output terminals, responsive to a position of displaceable contacts of the pair of potentiometers. Still further, the disclosure is directed to a system wherein the selective operative coupling between the pair of pickup coils and the output terminals that is provided by the pair of potentiometers additionally selectively provides the effective coupling of only one of the pair of pickup coils to the output terminals. Further, the system can provide selective operative coupling of one of said pair of pickup coils in combination with a series coupling of the pair of pickup coils, or can provide selective operative coupling of a the pair of pickup coils where the output provides contributions from both series and parallel coupling of the pair of pickup coils.
Electric string instruments, such as electric guitars, electric bases, electric violins, etc., use a pickup to convert the vibration of instrument's strings into electrical impulses. The most commonly used pickups uses the principle of direct electromagnetic induction. The signal generated by the pickup is of insufficient strength to directly drive an audio transducer, such as a loudspeaker, so it must be amplified prior to being input to the audio transducer.
Because of their natural inductive qualities, all magnetic pickups tend to pick up ambient electromagnetic interference (EMI) from electrical power wiring in the vicinity, such as the wiring in a building. The EMI from a 50 or 60 Hz power system can result in a noticeable “hum” in the amplified audio by from the audio transducer, particularly with poorly shielded single-coil pickups. Double-coil “Humbucker” pickups were invented as a way to overcoming the problem of unwanted ambient hum sounds. Humbucker pickups have two coils arranged to be of opposite magnetic and electric polarity so as to produce a differential signal. As ambient electromagnetic noise effects both coils equally and since they are poled oppositely, the noise signals induced in the two coils cancels out. The two coils of a Humbucker are often wired in series to give a fuller and stronger sound.
While most single coil pickups are wired in parallel with each other, it is also possible to wire them in series, producing a fuller and stronger sound. The two coils of a Humbucker type pickup can be connected in parallel. This results in a brighter sound, but at the cost of a lower output as with a single-coil pickup, but with the pickup's hum-cancelling properties still being retained. Using a multiple pole, multiple through switch, such as a double pole, double through switch (DPDT) or double pole three position switch, it is known in the art to switch the coil configuration between series and parallel, and may also provide or “coil cut” configuration (a single coil output).
Blend potentiometers, usually formed by two potentiometers ganged together to be rotated by a single shaft, allow blending together outputs of two pickup coils in varying degrees, not unlike a balance control provided in stereo equipment. Blend potentiometers, however, do not accomplish switching of the coil configuration. In one known prior art system disclosed in U.S. Pat. No. 4,423,654, a tone control formed with a pair of ganged rheostats is connected to the two coils of a Humbucker type pickup. The operation of this tone control provides a series coil configuration at one end of the rotation of the control and a parallel configuration at the opposing end of the rotation thereof. Of the two rheostats used, the resistance element of one is configured to have substantially zero resistance (zero ohms) between one end terminal and the midpoint of the resistance element's length and thereafter increase linearly, while the other rheostat has a resistance that increases logarithmically along its length. Due to the logarithmic taper of the resistance element, from the one end of the travel of the control that provides a series configuration of the coils to and including the midpoint thereof, the series configuration is maintained, changing only the high frequency attenuation included in the control.
A variable tone configuration control for string instruments is provided. The variable tone configuration control includes a pair of pickup coils disposed on a string instrument for inducing voltages therein responsive to vibration of at least one string of the string instrument. The variable tone configuration control further includes a pair of potentiometers each having a displaceable contact. The pair of potentiometers are mechanically coupled for concurrent mechanical travel of the displaceable contacts thereof. The pair of potentiometers are coupled to a pair of output terminals and one of the potentiometers is electrically connected to a single one of the pair of pickup coils. The pair of potentiometers provides selective operative coupling of the pair of pickup coils in a series connection between the output terminals, or selective operative coupling of the pair of pickup coils in a parallel connection between the output terminals, responsive to a position of the displaceable contacts.
Additionally, the selective operative coupling between the pair of pickup coils and the output terminals provided by the pair of potentiometers additionally provides effectively coupling only one of the pair of pickup coils to the output terminals responsive to another position of the displaceable contacts. The selective operative coupling between the pair of pickup coils and the output terminals further provided by said pair of potentiometers provides selective operative coupling of the one of the pair of pickup coils in combination with a series coupling of the pair of pickup coils, or the one of the pair of pickup coils in combination with a parallel coupling of the pair of pickup coils responsive to further positions of the displaceable contacts.
From another aspect, a variable tone configuration control for string instruments is provided that includes a pair of pickup coils disposed on a string instrument for inducing voltages therein responsive to vibration of at least on string of the string instrument. Each of the pair of coils has a respective first and second terminal. The variable tone configuration control further includes a pair of potentiometers each having a displaceable contact. The pair of potentiometers are mechanically coupled for concurrent mechanical travel of the displaceable contacts thereof. Each of the displaceable contacts are coupled to the first terminal of a respective one of the pair of pickup coils. Each of the pair of potentiometers has a respective pair of terminals coupled to opposing ends of a resistive element thereof at corresponding end positions of the mechanical travel, one of the pair of terminals of each of the pickup coils is coupled to a respective one of a pair of output terminals to thereby provide selective operative coupling of the pair of pickup coils coupled in series to the output terminals responsive to the displaceable contacts being positioned at one end of the mechanical travel or the pair of pickup coils coupled in parallel to the output terminals responsive to the displaceable contacts being positioned at an opposing end of the mechanical travel, or a series combination of the pair of pickup coils coupled in parallel with one of the pair of coils responsive to the displaceable contacts being positioned at other than one of the ends of mechanical travel.
Referring to
As is known in the art, one or more magnetic pickup coils are positioned in correspondence with the strings of the instrument so that they are able to produce an electrical signal in response to vibration of at least one of the multiple strings of the instrument. Humbucker type pickups are commonly used with electric string instruments because they provide for cancellation of electromagnetic interference (EMI), such as the 50 or 60 Hz “hum” that is induced from nearby electrical power wiring. Humbucker type pickups typically have two pickup coils in a single package that are phased to provide cancellation of “out of phase” signals. A pair of separately located single coils can also be connected with opposing respective phases to provide cancellation of EMI. Tone blend configuration control 100, 100′ may incorporate a pair of collocated coils as well as separately located coils in any phase relationship and located anywhere along the longitudinal extent of the strings on the instrument. Thus, they may be phased to provide noise cancellation or not, without departing from the inventive concepts embodied in tone blend configuration control 100, 100′. Both series and parallel modes can be phased for hum canceling, while in the single coil mode, there will not be a hum canceling feature. Where an instrument uses multiple Humbucker type pickups, each would be associated with a tone blend configuration control 100, 100′ and conventional switching or blend controls to select or mix the signals therefrom.
Referring now to
The output signal level of tone blend configuration control 100 may be on the order of 100-500 mV, which can then be reduced by adjustment of volume control 200. Audio amplifier 300 increases the signal level, voltage and current, sufficiently to drive an audio transducer 400, such as headphones or one or more speakers. The output terminals 306 of audio amplifier 300 are connected to the input terminals 402 of audio transducer 400. Although, audio amplifier 300 is shown with a sing pair of output terminals, it should be understood that multiple separate outputs may be provided to simultaneously drive a plurality of audio transducers 400.
Turning now to
Potentiometer 130 has a resistance at 0% output with respect to terminal 136 over the initial 50% of mechanical travel of the displaceable contact 138 from the end connected to terminal 136 defined by the element portion 133, and increases linearly (linear taper) from 0% to 100% over the remaining 50% of the travel, defined by the element portion 132. While potentiometer 140 is constructed oppositely, with the resistance with respect to terminal 146 decreasing linearly (linear taper) from 100% to 0% over the initial 50% of mechanical travel of the displaceable contact 148 from the end connected to terminal 146 defined by the element portion 142, and remains at 0% over the remaining 50% of the travel, defined by the element portion 143. In some applications the musician who owns the string instrument incorporating tone blend configuration control 100 may prefer a nonlinear resistive taper, such as logarithmic taper which is also known as an audio taper, for either or both of potentiometers 130 and 140. Regardless of the taper, tone blend configuration control 100 will function as described herein with respect to the pickup coil configurations at the endpoints of mechanical travel of the displaceable contacts 138, 148 and at the midpoint of the mechanical travel.
Pickup coils 110 and 120 may be two separately mounted coils located on the instrument, each in proximity to the strings 10 at different locations along their extent or two collocated coils that are provided in a single package. Both types of pickup coils are well known and widely available. In one working embodiment, pickup coils 110 and 120 were implemented with a humbucking series EMG-HZ type pickup available from EMG, Inc. of Santa Rosa, Calif.
The following connections apply to each of
The functioning of tone blend configuration control 100 will now be described, beginning with the displaceable contacts 138, 148 being at a first end of their respective mechanical travel, as shown in
From terminal 112, the current I1S flows through conductor 154 to terminal 149 of potentiometer 140, and from there through displaceable contact 148 to terminal 146. Again, for practical purposes, no current flows to terminal 144 of potentiometer of 140. The current I1S flows through conductor 166 to terminal 136 of potentiometer 130 and through displaceable contact 138 to terminal 139. From terminal 139 of potentiometer 130, the current I1S flows through conductor 156 to terminal 124 of pickup coil 120. The current I1S flows through pickup coil 120 to terminal 122 and through conductors 162 and 160 to positive output terminal 102; thereby completing the current path through tone blend configuration control 100. Clearly, as the same current, I1S, flows through both pickup coils 110 and 120, the pickup coils are coupled in series. For series coupled pickup coils, the voltages generated in the coils is additive, but provide a higher impedance to higher frequency audio signals and hence they are said to provide a fuller and stronger sound.
Turning now to
Starting again at negative output terminal 104, the current I1AB flows to terminal 114 of pickup coil 110 through the conductor 152. As the resistance between terminals 134 and 139 of potentiometer 130 is zero ohms, the current flowing to terminal 114 divides into a current I1A flowing through the pickup coil 110 and a current I1B flowing to terminal 134 of potentiometer 130 through the conductor 158. The current I1A flows from terminal 112 of pickup coil 110 to terminal 149 of potentiometer 140 through the conductor 154. From terminal 149 the current I1A flows through the displaceable contact 148 to terminal 144, and from there to node 165 through conductor 164. Due to the resistance of both resistive elements 142 and 132, no current flows from displaceable contact 148 to terminal 146, as it is negligible.
The current I1B flows from terminal 134, through displaceable contact 138 to terminal 139 of potentiometer 130. From terminal 139, the current I1B flows to terminal 124 of pickup coil 120 through the conductor 156. Current I1B flows through pickup coil 120 to terminal 122 thereof and through conductor 162 to node 165. At node 165 the currents I1A and I1B combine to define the current I1AB flowing through the conductor 160 to positive output terminal 102. Hence, the potentiometer setting in this example provides two parallel branches with a respective one of the two pickup coils in each branch. The parallel configuration results in a common voltage being generated by the pickup coils, a lower voltage than provided with the coils connected in series, but with a reduced high frequency impedance and thereby is said to produce a brighter sound.
Tone blend configuration control 100 provides neither a series configuration of pickup coils 110 and 120 nor a parallel configuration thereof when the displaceable contact 138 and 148 of potentiometers 130 and 140 are set to the midpoint of their mechanical travel. As shown in
A current I1 flows from negative output terminal 104 to terminal 114 of pickup coil 110 through conductor 152. The current I1 Flows through the pickup coil 110 to terminal 112 and through the conductor 154 to the displaceable contact terminal 149 of potentiometer 140. As in the exemplary condition discussed with respect to
It can be seen from the examples illustrated in
Referring to
A current I1AB flows from the negative output terminal 104 through conductor 152 to terminal 114 of pickup coil 110 and through that pickup coil to terminal 112, conductor 154 to the displaceable contact terminal 149 of potentiometer 140. The current I1AB flows through the displaceable contact 148 and divides between resistive element portions 142a and 142b. The current I1AB divides in inverse proportion to the resistance values (directly proportional to the conductance) of the resistive element portions 142a and 142b. Thus, a current I1A flows from terminal 144 of potentiometer 140, having flowed thereto through the resistive element portion 142a and element portion 143, to node 165 through conductor 164. A current I1B flows through resistive element portion 142b to flow from terminal 146 of potentiometer 140 to terminal 136 of potentiometer 130 through conductor 166. Current I1B flows through the element portion 133 and displaceable contact 138 to terminal 139. From terminal 139 of potentiometer 130, the current I1B flows to terminal 124 of pickup coil 120 through conductor 156, through that pickup coil to terminal 122, and then to node 165 through conductor 162. At node 165 the currents I1A and I1B combine to define the current I1AB which flows from node 165 through conductor 160 to positive output terminal 102. Thus, the total current exiting terminal 102 and returning to terminal 104, identified as the current I1AB, flows through pickup coil 110. Whereas, only a portion of the current that passes through pickup coil 110 (I1AB) flows through pickup coil 120, thereby providing a blending of the series and parallel effects.
To better see the series and parallel current flows, refer now to
Referring now to
The current I1A flows through the resistive element portion 132a and displaceable contact 138 to terminal 139. From terminal 139, current I1A flows through the conductor 156 to terminal 124 of pickup coil 120. Not unlike the example illustrated in
Turning now to
Thus, we begin to look at tone blend configuration control 100′ by considering the circuit with the displaceable contacts 138 and 148 set at the midpoint of their mechanical travel. The current I1AB flows from the negative output terminal 104 to terminal 114 of pickup coil 110, where the current divides with one portion I1A flowing therefrom through conductor 158 to terminal 134 of potentiometer 130′. The other portion I1B of current I1AB flows through pickup coil 110 to terminal 112 and on to the displaceable contact terminal 149 of potentiometer 140′ through conductor 154. The current I1B flows through the displaceable contact 148 and divides in the resistive element 142′ to establish a current I1B2 flowing through the resistive element portion 142a′ and a current I1B1 flowing through the resistive element portion 142b′. The current divides in proportion to the conductance of the resistive element portions 142a′, 142b′, which in this particular example are equal when the displaceable contact 148 is at the midpoint of its mechanical travel. The current I1B2 flows through resistive element portion 142a′ to terminal 144 and continues through the conductor 164 to node 165. The current I1B1 flows through resistive element portion 142b′ to terminal 146 and therefrom to terminal 136 of potentiometer 130′ via conductor 166. The current I1B1 flows from terminal 136 to the displaceable contact 138, and the current I1A flows from terminal 134 through resistive element portion 132a′ to displaceable contact 138 to combine with the current I1B1. The resultant current of the combination of I1A and I1B1 is designated I2 and flows to the displaceable contact terminal 139 of potentiometer 130′. From terminal 139, the current I2 flows through the conductor 156 to terminal 124 of pickup coil 120. The current I2 flows through pickup coil 120 to terminal 122 and through conductor 162 to the node 165, where the current I2 combines with the current I1B2 to define the current I1AB flowing from node 165 to the positive output terminal 102. Thus, at the midpoint of the mechanical travel there is a component of the total current that flow through the series arrangement of the pickup coils and components that flow through the pickup coils in parallel.
Referring now to
As a consequence of the resistive element portions 132b′, 142b′ being in series and the resistive elements 132′, 142′ having a linear taper, substantially no current will flow through the conductor 166 until the displaceable contacts 138, 148 are displaced from the second end of the mechanical travel to a position beyond the midpoint thereof. Accordingly, the pickup coils 110 and 120 remain in a parallel configuration, with a varying amount of series resistance when the displaceable contacts 138, 148 are positioned between the second end and midpoint of the mechanical travel thereof. Beyond the midpoint, a series current component is introduced and which increases, as the parallel current components decrease, as the displaceable contacts 138, 148 are positioned between the midpoint and the first end of the mechanical travel.
The position of the displaceable contacts 138, 148 with respect to the midpoint of the mechanical travel where the series current component is introduced can be altered to be more toward the second end by lowering the resistance value of resistive elements 132′, 142′. Another method by which the location where the series current component begins to be introduced can be shifted is by the use of potentiometers having resistive elements with logarithmic tapers arranged to increase in resistance from opposite ends to the mechanical travel. In fact, single pickup coil operation at or near the midpoint of the mechanical travel of displaceable contacts 138′, 148′, like that discussed with respect to
The descriptions above are intended to illustrate possible implementations of the present invention and are not restrictive. While this invention has been described in connection with specific forms and embodiments thereof, it will be appreciated that various modifications other than those discussed above may be resorted to without departing from the spirit or scope of the invention. Such variations, modifications, and alternatives will become apparent to the skilled artisan upon review of the disclosure. For example, functionally equivalent elements may be substituted for those specifically shown and described, and certain features may be used independently of other features, and in certain cases, particular locations of elements may be reversed or interposed, all without departing from the spirit or scope of the invention as defined in the appended Claims. The scope of the invention should therefore be determined with reference to the description above, the appended claims and drawings, along with their full range of equivalents.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2897709 | McCarty et al. | Aug 1959 | A |
| 3472943 | Takeshi et al. | Oct 1969 | A |
| 3544696 | Broussard | Dec 1970 | A |
| 3603713 | Nakada | Sep 1971 | A |
| 3663735 | Evans | May 1972 | A |
| 4222301 | Valdez | Sep 1980 | A |
| 4281573 | Yarema | Aug 1981 | A |
| 4405832 | Sondermeyer | Sep 1983 | A |
| 4423654 | Yamagami | Jan 1984 | A |
| 4532847 | Youngblood | Aug 1985 | A |
| 4581974 | Fender | Apr 1986 | A |
| 4581975 | Fender | Apr 1986 | A |
| 4819537 | Hayes et al. | Apr 1989 | A |
| 5136918 | Riboloff | Aug 1992 | A |
| 5311806 | Riboloff | May 1994 | A |
| 5569038 | Tubman et al. | Oct 1996 | A |
| 5761316 | Pritchard | Jun 1998 | A |
| 5932827 | Osborne et al. | Aug 1999 | A |
| 6121537 | Pawar et al. | Sep 2000 | A |
| 6998529 | Wnorowski | Feb 2006 | B2 |
| 7115810 | Ambrosino | Oct 2006 | B2 |
| 7271332 | Clark | Sep 2007 | B2 |
| 7304232 | Nicholes | Dec 2007 | B1 |
| 7601908 | Ambrosino | Oct 2009 | B2 |
| 7674991 | Baird et al. | Mar 2010 | B2 |
| 7982123 | Mulvany | Jul 2011 | B2 |
| 8253007 | Steinberger | Aug 2012 | B1 |
| 8324495 | Jacob | Dec 2012 | B2 |
| 20020073829 | Gaglio | Jun 2002 | A1 |
| 20020073830 | Petherick | Jun 2002 | A1 |
| 20030145715 | Wnorowski | Aug 2003 | A1 |
| 20040159225 | Barr | Aug 2004 | A1 |
| 20060156903 | Baird et al. | Jul 2006 | A1 |
| 20060156912 | Annis et al. | Jul 2006 | A1 |
| 20070006718 | Clark | Jan 2007 | A1 |
| 20090308233 | Jacob | Dec 2009 | A1 |
| 20100208916 | Jacob | Aug 2010 | A1 |
| 20100282046 | Crocker | Nov 2010 | A1 |
| 20100307325 | Appel | Dec 2010 | A1 |
| 20110017048 | Bos | Jan 2011 | A1 |
| 20110219942 | Robertson | Sep 2011 | A1 |
| 20110259180 | Gournis | Oct 2011 | A1 |
| 20140219477 | Scott | Aug 2014 | A1 |
| Number | Date | Country |
|---|---|---|
| 2207542 | Feb 1989 | GB |
| 2235562 | Mar 1991 | GB |
| 9213337 | Aug 1992 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 61859845 | Jul 2013 | US |
