Abstract:
A packaged preamp with an integral pickup, a battery holder, an output jack, and a plurality of control mechanisms. The packaged preamp can be mounted on a flat, curved, or variably curved side of an acoustic guitar body, such as a lower side away from the guitar player, while allowing optimal access to the output jack and the controls. The pickup is pre-wired into the preamp and requires only a mechanical attachment within the guitar. The output jack is integral to the preamp&#39;s front panel, the battery is accessed through a cover on the front panel, and the controls are accessed through the front panel. Once the pickup is attached inside the guitar, the packaged preamp is attached within a pre-cut opening in the side of the guitar, thereby completing the installation of the preamp.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority of U.S. Provisional Patent Application No. 60/407,537 filed Aug. 30, 2002 entitled PACKAGED PREAMP. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    N/A  
         BACKGROUND OF THE INVENTION  
         [0003]    The present invention relates generally to electronics enclosures and assemblies, and more specifically to a packaged preamplifier assembly mountable on a side of a musical instrument such as a guitar or similar stringed instrument.  
           [0004]    Enclosures for preamplifier (“preamp”) circuits are known that may be mounted on guitars and similar stringed instruments. A conventional preamp enclosure configured for use with an acoustic guitar is described in U.S. Pat. No. 6,278,059 (“the &#39;059 patent”) filed Nov. 3, 1999 entitled ELECTRONICS HOUSING HAVING A FLEXIBLE OUTER FLANGE and assigned to the same assignee as the present invention. As disclosed in the &#39;059 patent, the preamp enclosure is configured to hold a battery and to mount on either a flat or curved surface of the guitar body.  
           [0005]    Although the preamp enclosure described in the &#39;059 patent represents a significant advance in the art of electronics enclosures, it has several shortcomings. For example, the preamp enclosure does not provide for easily attaching a signal input to a preamp circuit housed within the enclosure. The preamp enclosure also has no provisions for easily accessing a signal output generated by the preamp circuit or for easily attaching the signal output to an output jack. Moreover, the manner in which a battery is secured and accessed within the preamp enclosure contributes a significant amount of mechanical complexity to the device.  
           [0006]    It would therefore be desirable to have a preamp assembly mountable on a side of a musical instrument such as a guitar or similar stringed instrument that avoids the shortcomings of conventional preamp enclosures and assemblies.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    In accordance with the present invention, a packaged preamplifier (“preamp”) assembly is disclosed that can be mounted on a flat, curved, or variably curved surface of a guitar body while providing easier pickup installation, easier output jack connection, and easier battery access. The presently disclosed packaged preamp achieves such benefits via a simplified construction that requires no wiring or soldering when installing the preamp in the guitar body.  
           [0008]    In one embodiment, the packaged preamp comprises a housing, a flexible mounting flange, a Printed Circuit (PC) board subassembly including a plurality of PC boards and at least one connector, at least one pickup for inputting an input signal, at least one output jack for outputting an output signal, and a plurality of control mechanisms, e.g., for volume and tone. The housing includes a battery holder with a captive cover that can be securely snapped into place. The plurality of PC boards is configured to hold all of the circuitry necessary for implementing the preamp. In the preferred embodiment, the control mechanisms comprise a pair of thumb-wheel potentiometer controls for adjusting the volume and tone.  
           [0009]    In a process of assembling the packaged preamp, the PC boards are interconnected via the connector. Next, the pickup leads are electrically shielded and attached to one of the PC boards. Battery terminals associated with the integral battery holder are then connected to one of the PC boards. Next, the output jack is directly attached to one of the PC boards. The PC board assembly is then inserted in the housing. Next, the flexible mounting flange is attached to the housing by one or more fasteners.  
           [0010]    Because of the simplified construction of the packaged preamp, manufacturing costs and installation costs are reduced, thereby allowing the device to be economically installed in a high volume of stringed musical instruments, including low-cost models. Further, because a typical installation of the packaged preamp requires no soldering and no modification of the instrument other than the preparation of an opening for the preamp device, the likelihood of assembly or installation error is significantly reduced, thereby resulting in fewer potential failure modes and increased reliability.  
           [0011]    Further, because the output jack is integrated with the packaged preamp, there is no need to drill a separate hole through the instrument to accommodate the jack. The packaged preamp functions as a structural reinforcement for the output jack, thereby obviating the need to provide a separate reinforcement in the event low-cost output jack models are employed.  
           [0012]    Moreover, the wiring for the packaged preamp is simplified because only the pickup leads need to be connected to the preamp—no separate cable is required to connect the output jack to the preamp circuitry. The internal assembly of the packaged preamp is also simplified by a PC board spacer that both separates and aligns the boards. Instead of welding the PC boards in place, the boards are friction fit onto the PC board spacer. In addition, the packaged preamp may be mounted on any side of the instrument to maintain optimal control usability.  
           [0013]    Other features, functions, and aspects of the invention will be evident from the Detailed Description of the Invention that follows.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0014]    The invention will be more fully understood with reference to the following Detailed Description of the Invention in conjunction with the drawings of which:  
         [0015]    [0015]FIG. 1 is a perspective view of a packaged preamp mounted on a side of an acoustic guitar according to the present invention;  
         [0016]    [0016]FIG. 2 is a perspective front view of the packaged preamp of FIG. 1;  
         [0017]    [0017]FIG. 3 is a perspective view of the packaged preamp of FIG. 1 showing a pre-wired pickup and an open battery holder;  
         [0018]    [0018]FIG. 4 is a perspective rear view of the back of the packaged preamp of FIG. 1;  
         [0019]    [0019]FIG. 5 is an exploded perspective rear view of the packaged preamp of FIG. 1;  
         [0020]    [0020]FIG. 6 is a perspective front view of an alternative embodiment of the packaged preamp of FIG. 1 including three control mechanisms, a pickup, and a microphone;  
         [0021]    [0021]FIG. 7 is a perspective view of a printed circuit board spacer included in the packaged preamp of FIG. 1;  
         [0022]    [0022]FIG. 8 is a flow diagram of a method of assembling the packaged preamp of FIG. 1; and  
         [0023]    [0023]FIG. 9 is a flow diagram of a method of installing the packaged preamp of FIG. 1 in a stringed musical instrument.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]    U.S. Provisional Patent Application No. 60/407,537 filed Aug. 30, 2002 entitled PACKAGED PREAMP is incorporated herein by reference.  
         [0025]    A packaged preamplifier (“preamp”) assembly is provided that is mountable on a side of a musical instrument such as a guitar or other similar stringed instrument. The presently disclosed packaged preamp includes a housing having an integral battery holder, and at least one Printed Circuit (PC) board disposed in the housing having pickup input leads and an output jack directly attached thereto, thereby allowing easier battery access, easier pickup installation, and easier output jack connection.  
         [0026]    [0026]FIG. 1 depicts an illustrative embodiment of a packaged preamp  12  mounted on a side of an acoustic guitar  10 , in accordance with the present invention. In the illustrated embodiment, the packaged preamp  12  is secured to the side of a lower bout  14  of the guitar  10  by a plurality of mounting screws  13  or any other suitable fasteners. It should be understood that the packaged preamp  12  may alternatively be mounted on a side of a hollow body electric guitar, a semi-hollow body electric guitar, a solid body electric guitar, a ukulele, a mandolin, a violin, a viola, a cello, a bass violin, or any other suitable stringed musical instrument.  
         [0027]    [0027]FIG. 2 depicts the packaged preamp  12  comprising a housing  21  that includes an electronics enclosure  64  and a battery holder  44 . The packaged preamp  12  further comprises a flexible outer mounting flange  22 , a face portion including an inner bezel  24 , a Printed Circuit (PC) board assembly  74  disposed within the electronics enclosure  64 , thumb-wheel volume and tone controls  26  and  28  and an output jack  42  disposed on the inner bezel  24 , and a captive cover  34  for the battery holder moveably coupled to the face of the packaged preamp. It should be noted that the packaged preamp  12  provides unobstructed access to the thumb-wheel volume and tone controls  26  and  28 , the output jack  42 , and the battery holder cover  34  disposed on the face of the device.  
         [0028]    Specifically, the flexible mounting flange  22  includes opposing flange end sections  25  for mounting the packaged preamp  12  on the side of the guitar  10  (see FIG. 1), a plurality of flange ligaments  23  interconnecting the end sections  25 , and a plurality of connecting ligaments  46  for connecting the mounting flange  22  to the electronics enclosure  64 . The flexible mounting flange  22  is attached to the electronics enclosure  64  by the connecting ligaments  46  and corresponding connecting ligament screws  50  (see FIG. 4).  
         [0029]    As shown in FIG. 4, connecting ligament openings  47  are separated from the electronics enclosure  64  by integrally molded connecting ligament spacers  48  (see FIG. 2). The ligament openings  47  are configured to give the connecting ligaments  46  room to bend when the flexible outer flange  22  is bent. The two substantially rigid outer flange sections  25  have a plurality of screw holes  40  formed therethrough and sized to accommodate the plurality of mounting screws  13  securing the packaged preamp  12  to the guitar. The outer flange sections  25  are connected to each other by the flange ligaments  23 , which are capable of bending to conform to a curved surface of the guitar body.  
         [0030]    As shown in FIG. 2, the battery holder cover  34  has a pair of pivot pins  38  disposed in corresponding slots  39  formed in the bezel  24  of the packaged preamp  12 , which further includes a plurality of cover retainers  36  for engaging corresponding locking surfaces  54  (see FIG. 3) on the cover  34 . Specifically, the pivot pins  38  and the corresponding slots  39  are configured to allow the closed cover  34  to slide, as depicted by a directional arrow  112  (see FIG. 2), a distance sufficient to free the cover locking surfaces  54  from the cover retainers  36 . The cover  34  may then be opened by rotating it, as depicted by a directional arrow  114  (see FIG. 3), about the axis of the pivot pins  38  to permit access to a battery  52  within the battery holder  44  (see FIG. 3). The cover  34  may be closed by rotating it, as depicted by the directional arrow  114 , to enclose the battery  52  within the battery holder  44 , and by sliding it, as depicted by the directional arrow  112 , into a locking position, thereby engaging the cover locking surfaces  54  under the cover retainers  36 .  
         [0031]    Battery terminals  62  (see FIG. 4) at least partially disposed within the holder  44  are configured to generate sufficient spring force to urge the battery  52  against ribs  35  (see FIG. 3) formed on an inner surface of the closed cover  34 , thereby securely engaging the cover locking surfaces  54  in the cover retainers  36  and avoiding any unwanted movement of the closed cover  34 . In this configuration, the battery holder cover  34  may be opened by combined actions of pressing and sliding the cover  34  to disengage the locking surfaces  54  from the retainers  36 .  
         [0032]    The battery  52  supplies power to preamp circuitry  75  (see FIG. 5) via the battery terminals  62  and battery terminal wires  60  (see FIG. 4). An output plug  15  (see FIG. 1) coupled to a shielded cable  16  (see FIG. 1) is configured to engage the output jack  42  and to actuate an internal shorting contact, thereby allowing the user to selectively turn the power “on” and “off”. As shown in FIG. 1, the cable  16  is connected between the plug  15  and an amplifier/speaker system  18 .  
         [0033]    As shown in FIG. 2, an output jack nut  30  and an output jack washer  32  are used to fasten the output jack  42  in place within the preamp housing  21 . Because the output jack  42  is connected to the PC board assembly  74 , the output jack nut and washer  30  and  32  not only secure the output jack  42  to the face of the housing  21 , but they also secure the entire assembly  74  within the electronics enclosure  64 . As shown in FIG. 4, the PC board assembly  74  comprises a plurality of PC boards, e.g., a PC board  70  for mounting the output jack  42  and a secondary PC board  72 , and a PC board spacer  55 . The combination of the PC board spacer  55  and a PC board connector including PC board connecting leads  56  joins the output jack mounting board  70  to the secondary board  72  in a predetermined fixed orientation.  
         [0034]    [0034]FIG. 7 depicts the PC board spacer  55 , which includes a spacer bar  57  having a respective circuit board support boss  59  at each end thereof, a plurality of PC board locating pins  58  emerging from the ends of the board support bosses  59 , a support member  80  transversely disposed relative to the support bosses  59  and the spacer bar  57 , and a guide rail  82  transversely disposed relative to the support member  80  opposite the bosses  59 . To properly orient the output jack mounting board  70  relative to the secondary board  72 , the PC board locating pins  58  are inserted through respective locating holes  73  formed in the PC boards  70  and  72  (see FIG. 4). Further, to secure the PC board assembly  74  to the electronics enclosure  64 , the guide rail  82  of the PC board spacer  55  is slidingly engaged in mounting rails  76  protruding from an inner surface of the enclosure  64 .  
         [0035]    As shown in FIGS.  4 - 5 , the output jack  42  and the thumb-wheel volume control  26  are mounted on the output jack mounting board  70 , and the thumb-wheel tone control  28  is mounted on the secondary board  72 . It is noted that the circuitry  75  for implementing the pre-amplification function may be disposed on one or both of the PC boards  70  and  72 . The packaged preamp  12  comprises a pre-wired pickup  90  including a pickup body  92 , a signal output lead  91 , a signal shield  89 , and a pickup cable  94  (see also FIG. 3), and a foil shield  88  (see FIGS.  4 - 5 ). In the illustrated embodiment, the pickup  90  is connected to the output jack mounting board  70  by attaching the signal output lead  91  to an input pad  84  and by attaching the signal shield  89  to a ground pad  86  disposed on the PC board  70  (see FIG. 5). Further, the foil shield  88  is disposed over the preamp circuitry  75  and the input and ground pads  84  and  86  on the PC board  70 , and connected to ground potential.  
         [0036]    The pickup body  92  is most conveniently installed by inserting it from the inside of the acoustic guitar  10  through a hole drilled through a bridge  11  (see FIG. 1) of the guitar. The pickup body  92  is then clamped between a saddle  17  (see FIG. 1) of the guitar and the bridge  11  by guitar strings  97  (see FIG. 1). In this way, vibrations in the strings  97  are mechanically coupled to the pickup body  92 , thereby inducing an electrical signal that is transmitted through the pickup cable  94 . The electrical signal appearing between the signal output lead  91  and the signal shield  89  is then transmitted to the preamp circuitry  75  via the input and ground pads  84  and  86  for subsequent processing.  
         [0037]    For example, the battery  52  disposed in the battery holder  44  may comprise a standard 9-volt battery or any other suitable type of battery. Further, the pickup  90  may be of the piezoelectric type or any other suitable type of pickup. Moreover, the housing  21  may be molded from a plastic material such as Nylon 6 or any other suitable material, and the battery holder lid  34  may be molded from a glass-filled plastic material or any other suitable material to increase its stiffness. In the preferred embodiment, the bezel  24 , the battery holder  44 , and the electronics enclosure  64  are molded as a single piece.  
         [0038]    An illustrative method of assembling the presently disclosed packaged preamp is illustrated by reference to FIG. 8. As depicted in step  802 , the connecting leads of the PC board connector are soldered through connecting pads (see the pads  77  in FIG. 4) on the secondary PC board. Next, the PC board spacer is attached, as depicted in step  804 , to the secondary board by inserting the PC board locating pins of the PC board spacer through respective locating holes (see the holes  73  in FIG. 4) in the board. The output jack mounting PC board is then attached, as depicted in step  806 , to the PC board connecting leads and the PC board spacer, thereby placing the output jack mounting board and the secondary board in the predetermined fixed orientation. It is noted that the PC board spacer is aligned so that the guide rail faces away from the output jack. Next, the preamp circuitry disposed on the PC boards is optionally tested, as depicted in step  808 . The pre-wired pickup is then connected, as depicted in step  810 , to the PC board assembly by soldering the signal output lead to the input pad and by soldering the signal shield to the ground pad. Next, the foil shield is placed over the PC board locating pins of the PC board assembly to cover the preamp circuitry and the input and ground pads, as depicted in step  812 . It is noted that the foil shield is connected to ground potential. The PC board assembly is then inserted, as depicted in step  814 , into the electronic enclosure by sliding the guide rail (as depicted by a directional arrow  116 ) between the mounting rails until the assembly contacts the bezel, thereby causing the thumb-wheel volume and tone controls to protrude through respective thumb-wheel openings (see the openings  29  in FIG. 5) and the output jack to press against a jack opening (see the opening  43  in FIG. 5). Next, the output jack nut and the output jack washer are attached, as depicted in step  816 , to fasten the output jack in place, thereby securing the entire PC board assembly within the electronics enclosure of the packaged preamp.  
         [0039]    An illustrative method of installing the presently disclosed packaged preamp in an acoustic guitar body is illustrated by reference to FIG. 9. As depicted in step  902 , an opening is formed for the packaged preamp at a desired location in the side of the guitar body by, e.g., drilling and/or cutting. A hole is then drilled, as depicted in step  904 , for the pickup body in the bridge of the guitar. Next, the pickup body is inserted, as depicted in step  906 , from the inside of the guitar body through the hole in the bridge for subsequent insertion into the saddle slot. The packaged preamp is then placed, as depicted in step  908 , within the side opening. The packaged preamp is then secured, as depicted in step  910 , to the guitar body by the plurality of mounting screws. Next, the saddle is installed, as depicted in step  912 , over the pickup inserted in the saddle slot. Finally, the guitar strings are installed, as depicted in step  914 , on the guitar.  
         [0040]    Having described the above illustrative embodiment, other alternative embodiments or variations may be made. For example, FIG. 6 depicts a packaged preamp  100  with a blend control  104  in addition to the volume and tone controls, as described above. The packaged preamp  100  further includes a pre-wired microphone  106  in addition to the above-described pre-wired pickup  90 . The pre-wired microphone  106  is connected to the PC board assembly  74  through a gooseneck connection  102 . Access to the thumb-wheel blend control  104  is added to the inner bezel  24  to allow the user to blend signals provided by the pre-wired pickup and microphone  90  and  106 . It should be understood that, in addition to or instead of the pre-wired pickup  90 , the packaged preamp  100  may alternatively include a vibration sensitive transducer, a force sensor, an accelerometer, a pressure sensor, or any other suitable input device.  
         [0041]    Further, the output jack may be alternatively configured for optionally supplying two separate channels of output signals. Moreover, depending on the preamp circuitry employed, the output signals may be provided either as a blended output signal or as two separate buffered signals via, e.g., a stereo jack.  
         [0042]    Other variations include soldering mechanical connectors such as terminal blocks to the input and ground pads, thereby allowing the pickup to be mechanically attached during assembly instead of being attached by soldering. Further, the battery holder cover may be joined so that motions other than pivoting, e.g., a purely sliding motion, may be employed for opening and closing the cover. Moreover, the battery terminals may be soldered directly to one of the PC boards without requiring wires to make the electrical connection. The flexible outer flange and the electronics enclosure may also be molded as a single piece.  
         [0043]    It will further be appreciated by those of ordinary skill in the art that modifications to and variations of the above-described packaged preamp may be made without departing from the inventive concepts disclosed herein. Accordingly, the invention should not be viewed as limited except as by the scope and spirit of the appended claims.