Patent Application
20050150364
The present disclosure is directed to an electromagnetic pickup system for stringed musical instruments and, more specifically, to an improved pickup and pickup system for stringed musical instruments.
The electrification of stringed musical instruments includes pickups to pick up the vibration of the strings and convert them into electrical signals. There are two main classes of pickups. One is electromagnetic pickups, which sense vibration of the string in a magnetic field. The other class is piezoelectric pickups, which contact the string and senses its movement. Many kinds of electromagnetic pickups have been designed for stringed instruments. These include single coils and dual hum canceling coils. The dual hum canceling coil is designed and wired to cancel the electric noises and interference picked up by the coils. The two coils have opposite magnetic and electrical polarities. The noise, which is electrically induced in the coils, cancel each other out.
The number of double and single coils along the strings of a musical instrument has varied in the industry. One example is two dual hum canceling coil pickups spaced along the strings with a single coil pickup in between. Various switching arrangements have interconnected the various coils. Switching has included connecting only one coil of the hum canceling pair of coils to the output circuitry. This is usually achieved by connecting the center tap between the two hum canceling coils to ground or to hot. Various impedances have also been connected with the coils to change their frequency response.
The present disclosure is directed a stringed musical instrument having a pickup system including at least one dual coil pickup, each coil having first and second end terminals and at least one tap to a portion of the coil between the first and second end terminals. A first or mode switch selectively connects first and second output terminals of a pickup circuit to (a) the first end terminals of both coils, (b) the first and second end terminals of one of the coils, and (c) the at least one tap of both coils. Selection (c) allows for less than a full coil of both coils. The tap is generally to a portion of between 55 and 80 percent of the winding between the first and second terminals. The second terminals of the first and second coils may be connected to each other for hum canceling.
The disclosed stringed musical instrument pickup system may alternatively include two dual coil pickups, each coil having first and second end terminals and at least one tap to a portion of the coil between the first and second end terminals. A first or mode switch selectively connects first and second output terminals of a pickup circuit to (a) the first end terminals of both coils of both pickups and (b) the taps of both coils of both pickups. In this embodiment, the mode switch changes both pickups simultaneously.
The musical instrument includes additional pickups and a second or pickup selector switch to selectively connect the pickups and the first switch to the first output terminal of the pickup circuit. The second output terminal of the pickup circuit is connected to ground. One of the additional pickups is a dual pickup having the first and second terminals and the tap. Another additional pickup may be a single pickup having first and second terminals.
The disclosure is also directed to dual coil pickup for a stringed instrument, the pickup having first and second coils having first and second end terminals. Each coil has at least one tap to a portion of the coil between the first and second end terminal. The second end terminals connect the two coils in a hum canceling arrangement between the first terminals and between the taps.
These and other aspects of the present disclosure will become apparent from the following detailed description of the disclosure, when considered in conjunction with accompanying drawings.
The pickups 32, 34, 36 are connected to circuitry within the musical instrument 20. Knob 40 is a tone knob, and knob 42 is a volume control knob. Knobs 40, 42 are shown as rotary potentiometers but also may be slide potentiometers. Switch 44 is a pickup selection switch to select interconnection of the pickups 32, 34, 36. Switch 46 is a mode selection switch to select between at least two hum canceling modes and single mode or configuration of the dual hum canceling coils 32, 36. Switches 44, 46 are shown as blade-type rotary switches, although they may be other types of switches, including digital switches. As will be explained in more detail with respect to
The dual hum canceling coils 32, 36 are illustrated in
For a full hum canceling effect (more amplitude and lower resonant frequency), the electronics are connected between terminals 2 and 5 of pickup 32. For less than a full hum canceling effect (less amplitude and higher resonant frequency), the output terminals are connected between taps 1 and 6 of pickup 32. For a single coil effect, the output terminals are connected to terminals 2 and 3 or 4 and 5. Single coil 34 has end terminals 7 and 8, with terminal 8 being connected to ground.
Dual hum canceling pickup 36 also has two coils D and E, each with two terminals and a tap. Terminals 10 and 11 are the first and second end terminals of coil D, with 9 being the tap to a portion of the coil between the first and second terminals 10 and 11. Coil E has first and second end terminals 12, 13 and a tap 14 to a portion of the coil between the first and second terminals 12, 13.
The taps 1, 6, 9 and 14 may be to a portion between 55 and 80 percent of the windings between the first and second terminals. Also more than one tap may be provided between the end terminals. The full and less than full hum canceling is a matter of personal taste and may vary.
A switching arrangement to allow full hum canceling or less than full hum canceling, as well as selection of single coil of the dual coil pickup(s), is illustrated in
Output terminals 15 and 16 are selectively connected to switch 44. Switch 44 is shown as a two-pole, five-position switch of the prior art. Other pickup selection switches may be used. In the first position of switch 44, pickup 32 alone is selected. Depending upon the position mode switch 46, it will either be full hum canceling, less than full hum canceling or a single coil of pickup 32. In the second position, pickup 32 and single coil pickup 34 are selected. In the third or center position, only the single coil pickup 34 is selected. In the fourth position, single coil pickup 34 and pickup 36 are selected. In the fifth position, only pickup 36 is selected. Thus, while mode switch 46 selects the configuration of the pickups 32, 36, selection switch 44 selects the interconnection of the pickups 32, 34, 36. The position of the switch 44 connects switch 46 to the hot or plus output terminal 18. Output terminals 17 and 18 represent the output terminals of the pickup circuitry, which are connected to electronics in the musical instrument or exterior to the musical instrument.
While
Although the dual hum canceling pickups 32, 36 are shown as horizontally adjacent pickups on a common carrier, they may be stacked pickups or mounted vertically adjacent to each other on a common carrier. Switch 46 shows the ability of selecting full hum canceling, less than full hum canceling or single coil. Switch 46 may also be a two position switch which selects between full hum canceling and less than full hum canceling or a plural position switch for plural taps. Switch 44 shows the interconnection of various pickups 32, 34, 36. Switch 44 is but an example of the interconnection of a number of additional pickups. Other selections may be made at switch 44. All of the switches may be digital switches.
Although the present disclosure has been described and illustrated in detail, it is to be clearly understood that this is done by way of illustration and example only and is not to be taken by way of limitation. The scope of the present disclosure is to be limited only by the terms of the appended claims.
