Patent Publication Number: US-2023162711-A1

Title: Modular headless stringed musical instrument for travel portability with enhanced serviceability and quickly replaceable neck joint and tremolo systems

Description:
FIELD OF THE INVENTION 
     The present art pertains to electric guitars and other stringed musical instruments and various components thereof. More specifically, the present art pertains to a headless modular electric guitar or any such musical instrument as is arranged to be readily disassembled into a plurality of independent modules chiefly for portability and to be readily assembled or reassembled into any such functioning and playable instrument. 
     BACKGROUND OF THE INVENTION 
     The guitar has been one of the most popular instruments, if not the most, for the past few centuries thanks to its multi-timbral capability and the singing quality of the melody performed on the instrument both available in reasonably portable dimensions and weight of the instrument. In particular, electric guitars have significantly contributed to the popularity of music today since their invention in the mid-twentieth century, as they are designed for electric amplification through options of signal processing, and thus can cater to a variety of instrumentations and their increasingly sizeable audiences by scaling the amplification up or down as appropriate. As today&#39;s digital technology has allowed for the virtualization of a significant part of the electric signal chain of the instrument, there are extremely portable yet capable options made available for the signal processing and amplification of the output signal of the electric guitars, allowing for the instrumentalists to take advantage of the public address systems available on-site without bringing their own physical amplification systems, and therefore without the inherent risks of damage or failure of any such amplification systems. Meanwhile, the electric guitar instrumentalists of today or in the history thereof overwhelmingly prefer or have preferred the designs of more conventional guitars that have made the history of popular music to the later and more portable alternatives. As such, the vast majority of the electric guitar instruments have closely maintained their historically defined size measurements and designs without any additionally portable functionality, while the remainder of the electric guitar signal chain has been digitally virtualized in a personal computer or smart device without any measurable physical dimensions. Albeit any virtualized guitar cannot be an alternative to the physical electric guitar instruments for the instrumentalists skilled in traditional electric guitar performances, the majority preference to the historic instruments is the single longest standing roadblock before its next logical step towards downsizing which would maximize the mobility of the instrumentalists while taking advantage of the downsized signal processing and amplification. 
     The preferred conventional electric guitars comprise a neck, a body, and a set of six or more strings. The typical joining methodologies of the neck and the body comprise so-called “set-in” wherein the neck is permanently or non-detachably attached to the body with an adhesive agent or other mechanical means, so-called “bolt-on” wherein the neck is semi-detachably attached to the body with a plurality of wood screws disposed through a supporting structure or any other threaded mechanical means, and “neck-thru” wherein the neck is extended through the length of the body and constitutes an integral part of the body. The neck comprises a fretboard longitudinally overlaying the neck and facing the strings, a headstock at the outermost end thereof, and a heel at the back of the opposite end of the headstock. The neck further comprises a plurality of machine tuners on the headstock, a plurality of frets on the fretboard periodically disposed across the length thereof, and a nut at or in the proximity of the limit between the fretboard and the headstock. Of all the joint variations, the bolt-on joint comprises one or a plurality of wood screws disposed through a metal neck plate or one or a plurality of other reinforcing structures, body, and into the mounting surface of the neck at the proximity of the heel thereof, wherein the helical threads of the screw secure the neck onto the body. Typical electric guitar strings are made of steel and comprise a ball-end at one end or less typically both ends to facilitate the replacement of the strings, while the other electric guitar strings comprising steel, nylon and fluorocarbon strings used for the electric guitars do not comprise any such ball-end as needs to be removed upon installation or as is not required for installation to an instrument, or otherwise as needs to be attached or configured by a knot in order to install on an instrument. An installed string is loaded with adjustable tension. One end of a string is attached to the peg of the machine tuner for tension adjustment mounted on the headstock at the end of the neck, while the other end of the string is attached to a saddle mounted on the body. Further, the set of strings is held in an array of grooves on a nut and another array of grooves at a bridge mounted at the defined position on the body under the set of strings in the proximity of the saddle. The tensions of the strings are adjusted to produce the desired tonal pitches by the corresponding machine tuners which raise the pitch higher by increasing the tension or lower by reducing the tension. The bridge and the saddle may optionally constitute, most typically, an integrated tremolo bridge assembly for a synchronized tremolo system or, less typically, one of the other kinds of tremolo system which may be disposed on the bridge, saddle, or across the bridge and saddle. A typical tremolo system is operated with an operating handle or whammy bar to allow instrumentalists to pivotally modulate the tension of the strings and therefore the sonic frequencies produced by the strings on the fly. The tremolo system typically comprises a bridge assembly, a lever structure comprising a base plate and a block, one or a plurality of fulcrum members to pivotally hold the lever structure of the system on a supporting structure of the body, one or more tension or compression springs counterbalancing against the string tension, and a whammy bar, and pivotally mounted by means of a plurality of studs, fixing screws, spring claw plate and other supporting structures on the body. The bodies of the electric guitars enabled with a tremolo, inter alia a synchronized version thereof, most typically comprise one or a plurality of recesses or cavities of significant volume that are not found on the other electric guitars configured without a tremolo, or “hardtail” electric guitar instruments, in order to accommodate the tremolo system within the body, affecting the tonal quality of the instruments. Most of the tremolo systems are arranged to hold the strings in tune with the tension of the strings on one end of the lever structure and the counterbalancing force of the springs on the other end thereof being in balance. The instrumentalists typically actuate the system by applying a variable or constant force to the whammy bar, pressing down to the body or pulling up away from the body with their right hand in the proximity of the picking or strumming position over the strings on the body to cause an imbalance between the string tensions and the counterbalancing springs, thereby modulating the tensions of the strings and continuously bringing the pitches of the strings to higher or lower pitches than are tuned. The tremolo system resumes the balance between the string tensions and the counterbalancing springs when the instrumentalist releases the force applied on the whammy bar, after which the strings are brought back in tune as the lever regains the balanced position. The body further comprises one or a plurality of electronic circuits to convert the physical vibration of the strings to an electronic signal, adjust the signal, and then send the signal through a pair of output electronic terminals with or without such adjustment. The electronic circuit comprises a plurality of components optionally including without limitation one or a plurality of pickup microphones, resistors, capacitors, inductors, transformers, transistors, volume control assemblies, tone control assemblies, strips of lead wire, ribbon cables, hand-operated switches, circuit boards, shielding components, grounding components, integrated circuits, liquid crystal displays, light emitting diodes, power battery components, integrated radio-transmission systems such as Bluetooth signal transmitter, and output terminal components for removable audio cables, radio transmission systems, Universal Serial Bus (USB) connections, and TOSLINK connections. Conventional electric guitars may be configured as per a headless structure wherein the headstock of the guitar is unrecognizably minimized to the extent that the headstock component only includes one or a plurality of string attachment components that is/are generally integrated with the nut and without the set of machine tuners, and wherein the tuning functionality is solely provided at the saddle or bridge end of the set of strings with versions and variations of custom components specifically designed for the headless configuration of guitars. 
     Of all the features of the conventional electric guitar instruments and other stringed instruments as aforementioned, the neck joint, the nut and the bridge represent the criticality that defines the tonal characteristic of the guitar and other instruments as to how the vibration of the strings are dynamically transferred to the body to resonate. Among the presented options, the most popular conventional electric guitar instruments today comprise a bolt-on or set-in neck joint, a plastic or bone nut, and a metal bridge. 
     The portable electric guitars include a design or system to reduce the measurements of the conventional electric guitars to further facilitate the compact portability or storage or both of the guitar by means of downsized designs as, or a plurality of quickly detachable modules to be re-attached into, or a quickly foldable structure to be unfolded into, a playable electric guitar instrument. Some of the embodied portable electric guitars comprise neck and body modules that make use of the string tension to reinforce the sturdy neck-body joint as the string tension is generally applied in such a way that pulls the neck and body modules together. 
     Of such popular optional design and system formats as aforementioned, the downsized designs comprise significantly different body sizes, body resonance and optionally shortened scale length or effective length of the strings for the players to re-orient. To compensate for the difference, some of the downsized designs include one or a plurality of detachable modules to outline the shape of more conventional designs, making them a sort of modular designs comprising an integrated body and neck module and one or a plurality of frame modules outlining the conventional body shape. While modular designs of this kind achieve lighter and laterally advantageous portability at the cost of more conventional body resonance, their longitudinal measurement remains comparable to the conventional full-sized instruments that may not conform to applicable luggage regulations and requirements in the course of transportation thereof, so that these specific types of modular approach are auxiliary and are of “downsized” instruments in spirit. Another type of modular design includes detachable neck and body modules to conform to any such luggage regulations to be removably reattached to configure instruments with conventional body size and its resultant tonal quality, but at the cost of additional steps to attach and detach the body module and the neck module which often include removal and reinstallation of the string tension using conventional machine tuners. The collapsible designs facilitate such attaching or detaching steps by maintaining the connection between the body and the neck in a collapsible or foldable manner which less often includes removal and reinstallation of the string tension with conventional machine tuners, but more often includes complex mechanisms compared with the modular designs. The complex mechanisms may expose the instrument to additional risk of damage and may result in tonal quality further deviating from the conventional design with significantly different key parts or components from the conventional alternatives. 
     Meanwhile, the acceptance of the portable guitars as more portable alternatives by instrumentalists who are mainly playing the other non-portable conventional electric guitars is subject to a variety of aspects thereof, comprising the components that best preserve the tonal quality, play-ability, serviceability, and customizing options with the replacement parts and components made available for the other non-portable conventional electric guitars. For the foldable and modular alternative formats, because the alternative formats have the advantage that can allow for achieving comparable body dimensions and therefore resultant tonal quality to the conventional instruments, the acceptance largely depends on the critical components comprising the neck joints involved in the streamlined steps to detach or collapse and to re-attach or unfold, wherein the modular designs are even more advantageous to achieve the comparable tonal quality of the conventional bolt-on design over the foldable or collapsible formats that often comprise more complex additional parts or components, further deviating from the conventional designs by accommodating any such parts or components occupying more space inside the instruments. 
     For the modular, foldable, and collapsible designs, several attempts have been made to streamline such steps by introducing an increased number of non-generic or non-conventional components which are designed exclusively for a particular portable embodiment. Thanks to such non-conventional components, some of the attempts have achieved extremely streamlined assembling and disassembling, folding and unfolding, or extending and collapsing steps with the increased number of mechanically movable and statically affixed parts comprising such non-conventional or non-generic components. However, any such increased number of parts in the exclusive and often complex components not only represents increased chances of failure or accidental damage, but also introduces degraded serviceability and accessibility of replacement components and parts thereof in case of failure or accidental damage thereof, due to the complex nature of the increased number of mechanically movable or pivotal parts and statically affixed parts. The damage-resistant durability through transportation and the resiliency against any such failure and damage, that is to say, the accessibility of replacement components and parts and serviceability thereof in case of failure or damage at the travel destinations are highly desired by both vocational performers and leisure hobbyists for their musical instrument embodied for the purpose of portability, as any such failure or damage is actually emerging, or as the insurance for peace of mind. 
     Furthermore, the tonal quality of the conventional non-portable electric guitars comprising a bolt-on feature is characterized by the optimal wood-to-wood contact between the body and the neck by means of a plurality of wood screws and tight-fitting neck pocket accepting the neck thereof as well as its resultant body resonance. However, the aforementioned non-conventional components comprise, as a whole or in significant part, metal-to-metal fixation or other non-conventional fastening or fixation of the quickly removable or collapsible body and neck, resulting in the tonal characters deviating if not degrading more or less from the generally preferred conventional non-portable electric guitars comprising a bolt-on feature. The conventional tight-fitting neck pocket also contributes to the stable tuning of the strings on the instrument, or the prevention of the strings from tuning modulation, or detuning, resulting from the neck being displaced in the range of the possible play in the neck pocket. 
     However, the tight-fitting neck contradicts the concept of facilitated assembling and disassembling steps of the portable embodiments of the traditional guitars, and may represent a risk of damage if not handled by a skilled guitar builder or service personnel. The several attempts historically made to achieve the equivalent tonal quality and tuning precision to the conventional tight-fitting neck pocket have yet to see a version which sufficiently streamlines the assembling and disassembling being frequently performed as the portable travel instruments by the traveling instrumentalists, at the same time sufficiently contributing to the precision and stability of the tuned strings of the portable travel versions of the instrument for performances. 
     Four identified issues derived from the trade-off relationship include the tuning instability and deteriorated tonal quality of the looser neck pocket trading off against increased efforts and risk of damage involved in assembling and disassembling steps of the tighter neck pocket. The solutions employing extensive use of non-conventional and often complex and exclusive metal components and parts as found among the several attempts made have overwhelmingly focused more on maximally decreasing the assembling and disassembling efforts at the cost of the other three with the further additional cost of reduced damage resistant durability through the transportation and reduced resiliency against the failure and damage due to increased use of more complicated and less accessible non-conventional components and parts. 
     In addition to any such contradiction regarding body-to-neck joint systems, conventional tremolo systems represent a technical challenge to introduce in portable electric guitars comprising detachable neck and body modules. The difficulty is centered around the embodiment approach to mounting the tremolo system which is designed and embodied for non-portable electric guitars to the portable modular or foldable embodiments on an as-is basis, with little to no reasonable consideration to any such modular portable feature. 
     Albeit no tremolo system has been specifically designed for the modular embodiments, there are some available tremolo systems, inter alia such systems for headless guitars that are preferably suitable for modular portable electric instruments. However, the suitable tremolo systems also comprise significantly more exclusive components and parts than their more traditional alternatives, representing a disadvantage against the damage-resistant durability through transportation and reduced resiliency against the threatened failure and damage that should be preferably alleviated altogether for traveling instrumentalists. 
     More specifically, the tremolo systems for conventional non-portable electric guitars often call for additional labor-intensive steps and multiple tools for its removal, so that the travel instruments are folded or disassembled with the strings attached to one or both of the neck and body via tremolo of the instruments. However, it is known that any such string, inter alia when it is a steel string, remaining attached on the folded or disassembled body, neck or both are exposed to significantly more risk of string damage the consequence of which is the replacement of the strings, either individually or more often as a set. 
     Also, more specifically regarding the tremolo systems for headless guitars, with limited alternatives available for more traditional configurations, the systems are most often paired with a nut or nut assembly made of metal as is required by the designs thereof, especially the designs with string locking capability at the nut, with or without “passive” contribution to the facilitated removable attachment to the neck. While the bridges for electric guitars are made of metal more conventionally, the nuts for the most popular conventional electric guitars are made of plastic resin or animal bone material that characterizes the traditional tonal character of the instrument. As such, the tremolo systems for headless guitars most often represent a critically perceivable deviation from the traditional tonal quality of the electric guitar which allows for wider nut options for different tonal characters including but not limited to brass and other metal materials. To best support the conventional tonal quality of the electric guitar for modular portable instruments, the instrument should ideally allow traditional nut options with removably attachable strings in a facilitated manner. 
     Meanwhile, the functionality of the tremolo systems is such that the pitch modulation is achieved by the pivotally leveraged mechanism to increase, reduce or auto-recover or otherwise control the string tension which must also be controlled likewise in the assembling and disassembling steps of the modular embodiments of travel electric guitars. 
     BRIEF SUMMARY OF THE INVENTION 
     Considering all such situations as identified in the preceding Background section, the present art provides an overall design format of a modular portable headless electric guitar and other stringed instruments comprising a streamlined neck joint system solution to optimally reconcile the identified contradiction regarding the neck joint system, as well as a purpose-built tremolo system solution for modular portable electric guitar and other instruments, featuring fewer and more streamlined exclusive parts and components which make it possible to optimally and strategically employ the parts and components for non-portable conventional electric guitars in order to enhance the streamlined assembling and disassembling steps of the modular electric instruments together with the neck joint solution without degrading the damage resistant durability through the transportation and the resiliency against the failure and damage. 
     The neck joint system solution in the present art focuses on the mechanism of its assembling and disassembling steps to provide a single reconciling solution with fewer and more streamlined additional non-conventional components and parts to address all four identified issues with no or nominally additional setback. 
     The tremolo system solution in the present art is a purpose-built system for the modular guitar and other instruments offering cleaner re-attachably detaching capability, and focuses on the pivotally leveraging functionality of tremolo systems to reduce, resume, and otherwise control the string tension in the course of its usual operation as well as the streamlined neck configuration of the headless guitars, and facilitates the assembling and disassembling steps of the instruments by providing two actively and synergistically leveraging steps to assemble and disassemble, one at the tremolo system and the other at a neck-end lever structure on the top end crown of the neck module. 
     More specifically, the instruments of present art provide the neck-side ends of the strings with the same pivotally leveraging functionality as the tremolo systems for the string tension, and actively engage the neck-side functionality, together with such functionality of the tremolo system, in the assembling and disassembling steps of the instrument, in order to further and synergistically expedite the steps, in the same spirit of employing fewer and more streamlined additional non-conventional components and parts. 
     The present art further provides other advantageous features for the luthiers and traveling instrumentalists, including without limitation, customizing options comparable to the conventional non-modular electric guitars with a broader range of alternative components readily available on the market globally, and streamlined conversions between a tremolo-enabled full configuration and a hardtail configuration without tremolo functionality. 
     The aforementioned comparable customizing options, however often overlooked, are of significant advantage for the portable designs, because the broader options comprise updated versions of any such components, be it the latest esthetical upgrade or more technically advantageous features becoming available for the conventional electric guitars, liberating the instrumentalists from a sort of “manufacturer lock-in” situation wherein the instrumentalists are required to wait for upgrades before purchasing the highly complex parts and components exclusively from the manufacturer of their instruments. 
     To provide a solution for three of the four identified issues on the neck joint system, the instrument comprises an oversized cavity for the bolt-on neck joint, or “neck pocket” having back and two side longitudinal walls and a bottom lateral surface. The surfaces optimally counterfacing the corresponding surfaces of the neck module only include the back wall and the bottom surface, as it has oversized width between the two side walls enough for the walls to avoid contacting the corresponding surfaces of the neck module. 
     The cavity comprises two structures to hold the neck module in position, including a sagittal or front-to-back axial coupling structure in the proximity of the laterally medial top end of the cavity, and a transverse clamping structure around the bottom end of the cavity. 
     The axial coupling structure provides a fixed transverse position with a self-adjustable longitudinal position and allows the neck module to radially shift to a calibrated position. To allow the entry of the axial fastener structure on the neck module into the axial coupling structure on the body module, an open-ended slot is provided at the medial top end of the cavity extending downwardly to the central part of the cavity. 
     The transverse clamping structure provides an adjustably limited width at the bottom end of the side walls to clamp the neck module at two side surfaces of the cuboid bottom tip thereof, wherein two clamping points provide two laterally fixed positions at the bottom of the neck module. The position of the limited width is adjustable within the oversized width of the cavity. 
     By adjusting or calibrating the transverse position of the limited width against the transverse fixed position of the front-to-back axial coupling structure at the top end of the cavity, the radial angle of the neck module position against the body module can be calibrated around the front-to-back axis provided by the axial coupling structure which is still longitudinally self-adjustable. 
     Two transverse clamping positions defined by the transverse clamping structure and the axial position defined by the axial coupling structure represent the largest triangular formation available within the back wall of the cavity, wherein the segment between the clamping positions represents the base of the triangle and the axial position represents the top vertex, providing a rigid joint structure without any play between the neck module and body module to ensure the absence of tuning instability due to the removable joint system. 
     The neck module is vertically inserted from the top down along the back wall of the cavity without any friction against the side walls which do not limit but guide the neck module into the cavity, and with negligible friction against the counterfacing back wall up to the transverse clamping structure where the neck module is finally pressed into the limited clearance of the transverse clamping structure with additional force across a marginal segment of the overall longitudinal travel into the cavity to be set at a calibrated position. The neck module is vertically removed out of the cavity by firstly pulling the neck module upwardly out of the clamping structure for a marginal segment with additional manual efforts, and thereafter frictionlessly for the rest of the travel. Thus the efforts required to attach a neck to the conventional tight-fitting neck pocket as well as the inherent risk of damage thereto are not completely eliminated but strategically minimized without allowing for any tuning instability due to the removable joint system. 
     On the side walls, the area of wood-to-wood contact in the cavity has been completely lost to marginalize the assembling and disassembling efforts. On the back wall, the area of wood-to-wood contact is further marginally lost to allow the axial fastener structure to enter into the axial coupling structure which in turn ensures the strength of the contact across the major area of the back wall. 
     With respect to the remaining wood-to-wood contact area on the bottom surface, the contact is not structurally well-attended on conventional bolt-on joints, as the vast majority of the bolt-on joints comprise three to four wood screws disposed front-to-back and thus the vertical position of the neck is not effectively adjustable to ensure the wood-to-wood contact with sufficient pressure on the bottom surface to improve or in any way influence the tonal quality. 
     Meanwhile, the instrument of present art ensures the optimal wood-to-wood contact as the axial coupling structure allows for self-adjustment of its longitudinal position as the string tension constantly pulls the body module and neck module and therefore the two counterfacing surfaces together, and as the open-ended slot is disposed with a marginally additional length to accommodate the fastener so self-adjusting. 
     Overall, the optimal wood-to-wood contact area of the instrument of present art is completely lost on the side walls, marginally lost on the back walls, and, without any empirical evidence but based on the structural advantage of the present art, suffers no loss, or possibly gained certain extra on the bottom surface to compensate such losses on the other surfaces, compared to the wood-to-wood contact area of the conventional bolt-on guitars and other stringed instruments. The comparison results greatly vary depending on how precisely the conventional bolt-on guitars are built or adjusted in terms of the neck pocket and the counterfacing bottom segment of the neck. 
     The modular guitar or another instrument of present art further comprises a tremolo module solution that is attached to the body module by the string tension pulling the tremolo system upwardly into the rectangular cutout of the bottom of the body module to a bridge, and along the downward extension of the break angle of the strings at the bridge. 
     The tremolo module comprises a tremolo system that in turn comprises a saddle in the shape of a rectangular window, a plurality of machine tuners for guitars, a lever, a plurality of compression springs, and a whammy bar, of which the machine tuners and the whammy bar are replaceable with generally available replacement parts for conventional non-modular electric guitars, and of which the saddle and the lever are designed to accommodate the generic machine tuners and a whammy bar. 
     The compression springs are employed for more facilitated assembling and disassembling of the instrument to configure the counterbalancing springs to be removably attachable as a part of the tremolo module in a facilitated manner, wherein the compression springs are unloaded as a complete set when the string tension is removed, and do not require any such anchoring apparatus as found in the conventional tremolo systems that calls for intensive labor and additional tools. 
     The compression springs are installed in a transverse array under the top plate member of the lever, backwardly pushing against a transverse spring base plane disposed below the bridge in the proximity of and in parallel with the back side surface of the body module. 
     The machine tuners are disposed in two arrays facing each other on the front and back lengthwise segments of the frame of the window, in such a way that the string holes located on the posts of the machine tuners are laterally aligned in the middle of the window so that the string holes have mostly the same distance both from the bridge and a pivotal axis defined by two knife-edges to achieve the vibrato effects comparable more or less to conventional tremolo systems. 
     The posts of machine tuners are extending from the chassis of the machine tuners disposed on the outer walls of the lengthwise segments and into the window in a reciprocal manner from side to side. Both arrays of machine tuners have buttons extending downwardly from the outer walls of the lengthwise segments. 
     The saddle configuration allows for the strings extending closely in parallel from the top to the bottom of the instrument as is the case of some of the conventional tremolo systems, provides a single area of access for tension adjustment at the bottom opening of the cutout, and lastly but not the least, enables a headless and tremolo-enabled configuration for the instrument employing a set of conventional machine tuners. 
     The lever is designed to configure the relative positions of the compression springs, the pivotal axis of the tremolo system, and the string holes into an L-shaped pivotally leveraging configuration to dispose the comparable pivotal functionality of the conventional tremolo systems, at the same time allowing for facilitated removal of the tremolo system from the cutout. 
     The strings are mostly perpendicularly extending into the saddle along the extension of the break angle at the bridge, so that the saddle is held diagonally in the middle of the cutout between the front and back surfaces of the body module. The lever has two knife-edge tabs at the back bottom, laterally extending outwardly in parallel with the strings, and therefore perpendicularly to the upper surface of the saddle. The knife-edges are disposed into a couple of knife-edge mount notches that are disposed in parallel with the installed strings, on the saddle mount planes of the cutout, and oriented towards the knife-edges, and anchor the tremolo module against the string tension pulling the tremolo module towards the bridge, as the compression springs are pressed down to counterweigh at the opposite tip of the lever. 
     In the aforementioned L-shaped configuration, the saddle represents the bottom lateral segment of the letter “L” with the strings pulling the segment upwardly in the middle of the segment, and the compression springs are installed on the left side of the top tip of the longitudinal segment pressed into left thereof, and the knife-edges are supported by the supporting structure at the inside corner thereof. 
     When the string tension is removed, the set of compression springs is completely unloaded and therefore the tremolo module including the compression springs can be effortlessly removed, allowing for cleaner removal of the tremolo module compared to a typical conventional tremolo system wherein a plurality of tension springs may remain loaded, residually or otherwise, after string tension removal, and wherein the system calls for working on both front and back sides of the body using a plurality of tools as the conventional tremolo system is not designed for removable attachment. 
     The tremolo system of the present art is operated, pivotally functions and delivers the effects in the same manner as conventional synchronized tremolo systems, and further self-serves to remove the string tension for the removal of itself by its originally intended functionality to pivotally reduce, resume, or otherwise control the string tension by manually applied leveraging force, which also leverages and expedites the disassembling and re-assembling steps as the instrument of present art has both neck and tremolo modules relying on the string tension to maintain the integrity of the assembled configuration of the instrument. 
     The self-serving functionality to remove itself of the tremolo module is further facilitated on the other end of the strings disposed with a neck-end lever structure that is another actively leveraging functionality. As intended, the tremolo module solution comprises the set of strings and a part of neck-end lever structure apparatus to be removed as part of the tremolo module from the assembled instrument. 
     The neck-end lever structure includes a string retaining apparatus (SRA) holding the set of strings at the uppermost ends of the strings, and a string anchoring apparatus (SAA) at the uppermost end of the neck module and accepts the string retaining apparatus to anchor the strings at a set position. 
     In the exemplary embodiment, both SAA fixed on the neck module and SRA as a part of the tremolo module removably attached on the rear surface of SAA are a plate longitudinally disposed at the back of the uppermost segment of the neck module of an assembled instrument for the purpose of attaching one end of the strings with ball ends at the top end of the neck module in an actively leveraged manner. 
     SAA defines the top end of the neck module with its uppermost lateral edge, or a pivotal edge, and comprises a series of longitudinal string slots for the corresponding number of strings at its pivotal edge. The bottom edge of SAA extends across and is affixed on the crown of the neck module. A string slot is an open-ended slots extending upward to its open end at the pivotal edge. Each slot allows for the strings to enter and move along the slot, but does not allow the ball end to pass through the slot, thereby anchoring the strings at its ball end on the back surface thereof. As the strings are pulled diagonally down towards the string nut on the front side of the instrument, the ball end is anchored at the bottom of the slot on the back of SAA. 
     While SAA is capable of individually holding the strings without SRA, SRA actively facilitates the removable attachment by disposing a leveraging functionality to SAA. SRA comprises a lateral array of string apertures disposed along its uppermost lateral edge, or a lever edge, to hold all the strings on one plate at the ball ends thereof, as well as a lever tab, or downwardly prolonged plate area with a downwardly curved bottom edge. Said ball ends are lodged on the back side of SRA at the string apertures. The positions of string apertures are closely aligned with the positions of the string slots of SAA. The strings pass through the string apertures from the back side of the SAA before passing through the string slots of SAA to the front of the neck module and seating on the string grooves on the nut of the assembled guitar or another string instrument, so that SRA is clamped between the ball ends and SAA, and pressed down on the surface of SAA by the string tension pulling SRA towards the front. 
     On the exemplary embodiment of the instrument as assembled, the lever edge is positioned slightly above the pivotal edge that is slightly above the array of ball ends arrested on the array of string apertures. From top down, the lever edge, the pivotal edge, and the array of ball ends are laterally disposed and in parallel with one another and reasonably close to each other. 
     Said lever tab of the SRA allows for a manual operation to radially pry up the SRA from SAA at the bottom end of SRA from its pressed-down position of the assembled instrument. As the bottom end of SRA is lifted from the pressed-down position, the lever edge rotates around the pivotal edge defining the lateral axis of such rotation, and over to the front side of the SAA while the array of ball ends at the back of SRA are also lifted up and rotates together with SRA as the relational positions of the pivotal edge, the array of ball ends, and the lever tab represents a class-two lever configuration where the pivotal edge representing the pivotal axis of the fulcrum, the array of ball ends representing the load or resistance, and lever tab representing the effort points of the lever configuration. As the ball ends lift up from their completely installed positions, the string tension slightly increases. 
     The lever tab is downwardly prolonged enough to leverage the manually applied force to overcome any such increased tension, so that the array of ball ends continue to rotate around the pivotal edge over to the front of the SAA, thereafter the string tension decreases, and all the strings are detached from the neck module with the SRA. 
     When re-attaching the strings with the SRA to the SAA, the lever tab is radially pressed down to the SAA around the axis in the same actively leveraged manner as aforementioned to overcome the increased string tension when the ball ends are rotating over from the front to the back to snap SRA on to SAA. 
     The overall steps to assemble or re-assemble the instrument comprise a preceding step to remove part of the string tension by pressing and holding the whammy bar into the front body module surface or otherwise to bring the saddle closer to the bridge in order to further facilitate the subsequent step to manually operating the lever tab accordingly to overcome the pre-reduced string tension thereby. 
     The overall steps to assemble or re-assemble the instrument may also comprise a step to initially remove additional tension by rotating the machine tuners accordingly before proceeding to the steps as aforementioned, wherein such two leveraging functionalities at the opposing ends of the strings also synergistically make the overall steps effortless while further saving the risk of damage associated with excessive force being applied to the guitar or other instrument when assembling or disassembling. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front perspective view of an exemplary embodiment of the present art in full configuration. 
         FIG.  2    is a front perspective view of a body module of the exemplary embodiment of the present art. 
         FIG.  3    is a front perspective view of a tremolo module of the exemplary embodiment of the present art. 
         FIG.  4    is a front perspective view of a neck module of the exemplary embodiment of the present art. 
         FIG.  5    is a schematic illustration of a transverse clamping structure of the exemplary embodiment of the present art as assembled. 
         FIG.  6    is a front perspective view around a cavity with the exploded body module and neck module, comprising the transverse clamping structure and an axial coupling structure. 
         FIG.  7    is a back perspective view around a central recessed plane with the exploded body module and neck module, comprising the axial coupling structure and an axial fastening structure. 
         FIG.  8    is a schematic illustration around the axial coupling structure and the axial fastening structure of the body module and neck module as assembled. 
         FIG.  9    is a back perspective view around the axial coupling structure and the axial fastening structure of the body module and neck module as assembled. 
         FIG.  10    is an exploded front perspective view around a tremolo system with a set of strings removed and a cutout of the exemplary embodiment of the present art. 
         FIG.  11    is a bottom view of a saddle and machine tuners of a tremolo system of the exemplary embodiment of the present art with a set of strings removed. 
         FIG.  12    is a back view of the tremolo system of the exemplary embodiment of the present art with a set of strings removed. 
         FIG.  13    is a side plan view around the tremolo system of the exemplary embodiment of the present art as assembled in full configuration. 
         FIG.  14    is a front perspective view around a hardtail of the exemplary embodiment of the present art as assembled in hardtail configuration. 
         FIG.  15    is a front perspective view around a neck-end lever structure of the exemplary embodiment of the present art. 
         FIG.  16    is a rear perspective view around the neck-end lever structure of the exemplary embodiment of the present art. 
         FIG.  17    is a side plan view around the neck-end lever structure of the exemplary embodiment of the present art. 
         FIG.  18    is a front perspective view of a string retaining apparatus with a set of strings of the exemplary embodiment of the present art. 
         FIG.  19    is a bottom perspective view of the saddle as disassembled and isolated of the exemplary embodiment of the present art. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     To achieve the objectives of the present invention, the disclosure thereof is provided with an exemplary embodiment in the following detailed description with reference to the figures, given the premise that it is to be understood by those skilled in the art that the disclosure includes any possible alternative, modification, or equivalent within the spirit and scope of the invention as defined by the appended claims and claims equivalents as supported herewith. 
     In the exemplary embodiment of the present art, the instrument is an electric guitar  1  comprising a body module  17  ( FIG.  2   ), a neck module  20  ( FIG.  4   ), and a tremolo module  50  ( FIG.  3   ) detachably assembled into a complete and operational instrument following one or a plurality of expedited assembling or reassembling steps, to be re-attachably disassembled into the body module  17 , the neck module  20  and the tremolo module  50  following one or a plurality of equally expedited disassembling steps. 
     The body module  17  comprises a cavity  31  at the uppermost medial part of the front side of the body module  17  for removably securing the neck module  20  at a defined position, and a longitudinal rectangular cutout  46  through the front and back sides of the body module  17  at the center of the lowest end thereof for pivotally and removably securing the tremolo system  60  ( FIG.  10   ). The body module  17  further comprises a bridge  25 , a bridge recess  28 , an electronic circuit (not shown), a pickguard  104 , and three strap pins  129 . 
     The cavity  31  comprises one or a plurality of neck pins  106 , a transverse clamping structure ( FIG.  5   ), and an axial coupling structure ( FIGS.  6 ,  7 ,  8 , and  9   ). The transverse length of the cavity  31  is minimally oversized to completely eradicate the friction between the side walls of the cavity  31  and the side walls of the neck module  20  upon inserting the neck module  20 . 
     The cylindrical neck pin  106  is longitudinally disposed into a hole (not shown) on the bottom surface of the cavity  31 , and half of each neck pin  106  protrudes from the hole (not shown) and fits into a coupling hole (not shown) on the bottom tip of the neck module  20  in order to provide support during the steps to removably attach the tremolo module  50  to the assembled neck module  20  and body module  17  placed in a recumbent position, and to reinforce the bond between the neck module  20  and the body module  17  of the assembled instrument. The coupling hole of the neck module  20  is reasonably oversized to allow for the calibration range of the position of the neck module  20 . 
     A transverse clamping structure ( FIG.  5   ) of the exemplary embodiment comprises two roundhead clamp screws  142  disposed into a couple of counterbores  39  at two deepest corners of the cavity  31  to secure the bottom end segment of the neck module  20  without any play into a laterally fixed position as calibrated by rotating the two clamp screws  142 . 
     The counterbores  39  respectively comprise screw holes (not shown) coaxially aligned with the counterbores  39 , and are arranged in such a way that the clamp screws  142  are diagonally situated in the cavity  31  so that the smooth spherical surface of a roundhead  113  of the roundhead clamp screws  142  clamps the sides of the neck module  20  with sufficient friction at a precise transverse position as calibrated with the clamp screws  142 . The counterbores  39  are disposed in such a way the counterbores  39  sufficiently allow for the roundheads  113  of the clamp screws  142  to be adjusted flush with the corresponding side walls. 
     Another embodiment may comprise a structure to reinforce the regional parts of both sides of the neck module  20  in contact with the clamp screws  142  for the added prevention against wear on the wood surface due to the friction against the roundhead  113  of the clamp screws  142 , including without limitation a square metal plate attached flush with the side surface of the neck module  20  to cover the area in contact with the head of the clamp screw  142 . 
     The clamp screws  142  of the exemplary embodiment are strategically positioned to facilitate the streamlined assembling of the disassembled neck module  20  and the body module  17 . The oversized lateral clearance of the cavity  31  allows for the neck module  20  with the thumb screw  33  to be longitudinally slid down inside of the cavity  31  from the top without friction otherwise caused by the side walls of the oversized cavity  31 , except for the lowest or last marginal segment of the cavity  31  where the neck module  20  finally experiences the friction against the roundheads  113  of the clamp screws  142  as the roundheads  113  of the clamp screws  142  respectively protrudes from the side surfaces of the cavity  31  to sufficiently limit the clearance between the side walls to allow for the fully inserted neck module  20  to be removably set at a calibrated position without play. 
     In the course of the disassembling of the assembled neck module  20  and body module  17 , the neck module  20  experiences additional friction by the clamp screws  142  for the lowest or first marginal segment when longitudinally pulling out neck module  20  upwardly, followed by the remaining segment without friction otherwise caused by the side walls of the oversized cavity  31 . 
     The amount of friction applied to the side walls of the neck module  20  by the roundheads  113  of the clamp screws  142 , and therefore the clearance between the clamp screws  142  are calibrated by adjusting or readjusting the diagonally transverse positions of the clamp screws  142 . Likewise, the lateral position of the clearance between the clamp screws  142  within the cavity  31  is calibrated in the same manner. The positions of the clamp screws  142  are adjusted by rotating the clamp screws  142  clockwise or counter-clockwise as the case may be to dispose further into or out of the respective screw holes (not shown). 
     For example, the position of one side wall surface of the neck module  20  can be adjusted by removing the neck module  20  from the cavity  31  and rotating the relevant clamp screw  142  in contact with the side wall of the neck module  20  clockwise to dispose the roundhead  113  further into the counterbore  39 , and therefore reducing the portion of the roundhead  113  protruding from the side wall surface to adjust or readjust the neck module  20  side wall closer to the side wall of the cavity  31 , or by rotating the clamp screw  142  counter-clockwise to dispose the roundhead  113  further out of the counterbore  39 , and therefore increasing the portion of the roundhead  113  protruding from the side wall surface to adjust or readjust the neck module  20  side wall further away from the side wall of the cavity  31 . Thereafter the other clamp screw  142  is accordingly rotated clockwise or counter-clockwise as the case may be to dispose the roundhead  113  further into or out of the counterbore  39 , and therefore decreasing or increasing the portion of the roundhead  113  protruding from the side wall surface of the cavity  31  to apply sufficient friction to the both of the side walls of the neck module  20  to set at a calibrated position in the cavity  31 , allowing for no play inside the cavity  31 . 
     The axial coupling structure ( FIGS.  6 ,  7 ,  8 , and  9   ) of the exemplary embodiment comprises a central recessed plane  32 , a bolt slot  18 , and a U-shaped reinforcement plate  111 . The axial coupling structure ( FIGS.  6 ,  7 ,  8 , and  9   ) accepts the axial fastener structure ( FIGS.  6 ,  7 ,  8 , and  9   ) of the neck module  20  to removably secure the neck module  20  at the calibrated position together with the calibrated transverse clamping structure ( FIG.  5   ), wherein the axial coupling structure ( FIGS.  6 ,  7 ,  8 , and  9   ) sets a longitudinally adjustable lateral position with a sagittal or front-to-back axis of the thumb screw  33  of the axial fastener structure ( FIGS.  6 ,  7 ,  8 , and  9   ). The axial coupling structure ( FIGS.  6 ,  7 ,  8 , and  9   ) further ensures optimal wood-to-wood contact across the back wall of the cavity  31 . 
     Central recessed plane  32  in the uppermost medial part of the back side of the body module  17  provides a countersink  40  for the thumb screw  33  when the neck module  20  is assembled on the body module  17 . The countersink  40  is radially oversized to permit manual operation of the thumb screw  33 , and has a plane surface at the bottom of the recess that extends to the uppermost middle edge of the body module  17  to permit entry of the oversized head  103  and conical shank  37  of the thumb screw  33  at its free-hanging position (as later defined) into the plane surface, when the neck module  20  is inserted in the longitudinal direction from the uppermost side of the body module  17 . 
     The bolt slot  18  is an open-ended longitudinal slot disposed at the center of the upper most edge of the cavity  31 , and extending downwardly to the central part of the central recessed plane  32 . The bolt slot  18  accepts the threaded shaft  141  of the thumb screw  33  at its free-hanging position (as later defined) to be longitudinally inserted into the designated position frictionlessly, and guides the neck module  20  to the proximity of the defined position. The guiding functionality, together with the maximally reduced friction upon inserting the neck module  20  down into the oversized cavity  31 , aids in preventing any possible damage to the neck module  20  or the cavity  31  due to the neck module  20  being overly misaligned from the defined position or the excessive force to be otherwise exercised to insert the neck module  20  into the cavity  31 . 
     The back edge of the bolt slot  18  is lined with a U-shaped reinforcement plate  111  secured in the central recessed plane  32  with a plurality of wood screws  162 . The reinforcement plate  111  overlays the central part of the central recessed plane  32  extending to the outermost edge of the body module  17 . The reinforcement plate  111  provides a countersink  40  alongside the bolt slot  18  whereon the conical shank  37  of the thumb screw  33  is inserted and secured in a position defined as self-adjusted by the string tension for optimal wood-to-wood contact on the bottom surface of the cavity  31 . The bolt slot  18  and the reinforcement plate  111  have a marginally extra segment to accommodate any such self-adjusted position of the thumb screw  33 . The reinforcement plate  111  distributes the force from the conical shank  37  of the thumb screw  33  more evenly to the part overlaid by the reinforcement plate  111 , and furthermore evenly to the opposite side of the cavity  31  to maximize the rigid wood-to-wood contact across the counterfacing surfaces of the neck module  20  and the body module  17  on the opposite side of the cavity  31 . 
     The position of the neck module  20  on the body module  17  is precisely calibrated by laterally repositioning the clearance between the clamp screws  142  and therefore readjusting the radial position of the removably attached neck module  20  around the fixed sagittal or front-to-back axis defined by the thumb screw  33 . The results of such calibration can be verified with the positions of the two outermost strings  130  against the fretboard  56  on the assembled instrument. 
     Two points of the neck module  20  supported by the transverse clamping structure ( FIG.  5   ) at the deepest edge of the cavity  31  provides the base edge of the maximally large triangular formation, with the supported points representing its vertices, inside the cavity  31  together with the point supported by the thumb screw  33  at the uppermost part of the neck pocket, representing the uppermost vertex of the triangular formation. The triangular formation maximally reduces the leveraged force at the bottom end of the neck module  20  resulting from the excessive force applied accidentally or otherwise on the upper segment of the neck module  20  of the assembled instrument with the thumb screw  33  being the axial support point, and the clamp screws  142  representing two possibly farthermost points within the cavity  31  from the axial support. 
     In the exemplary embodiment, the instrument comprises a pickguard  104  that is a sheet of plastic resin overlaying a defined part of the front surface of the body module  17  to protect the surface, and to provide a mounting and enclosing means for the majority part of electronic circuit components (partly not shown). The pickguard  104  is attached to the body module  17  with a plurality of wood screws  163  strategically placed alongside the perimeter of the pickguard  104 . 
     The electronic circuit of the exemplary embodiment comprises three pickup microphones  105 , a volume control  154 , a tone control  143 , and a microphone selector switch  84 , a plurality of lead wire strips (not shown) establishing electrically conductive connections of such components attached to the respective cutouts on the pickguard  104 , and fitted inside an enclosed recess (not shown) on the front side of the body module  17  between the cavity  31  and the bridge recess  28  and covered by the pickguard  104 , and output jack  101  fitted at a separate recess and communication channel (not shown) on the lower right side surface of the body module  17 . The ground wire (not shown) extends to the bushing (not shown) of the bridge  25  via a communication channel (not shown) from the enclosed recess (not shown). 
     The strap pins  129  are longitudinally attached to the body module  17  with wood screws at the uppermost left side tip of the body module  17  and two lowest faces of the body module  17  at both sides of the opening of the cutout  46 . The strap pins  129  accept the attachment openings or strings at the two ends of conventional guitar straps (not shown). The two lowest strap pins  129  of the exemplary embodiment further provide seating feet of the assembled instrument in case the instrument in an upright position is perpendicularly placed on a flat surface. 
     The bridge  25  comprises a plurality of bridge grooves  27 , the mount bushings (not shown) and the height adjustment screws  67 , and is attached on the deepest plane of the transverse bridge recess  28  on the front side of the body module  17  and above and adjacent to the cutout  46 . 
     The bridge  25  together with the string nut  99  represents the critical points of the assembled instrument where the significant part of the vibration of the set of strings  130  is transferred to the body module  17  and the neck module  20 , significantly contributing to the tonal characteristics of the assembled instrument, the present art enables the conventional string nut  99  and bridge  25  on a headless configuration of the modular instrument with facilitated attaching and detaching functionality of the set of strings  130  to and from the instrument, thereby enabling the conventional tonal characteristics of the conventional nut and conventional bridge. 
     However, the bridge  25  is preferably a roller bridge variant of the available guitar bridges for conventional electric guitar instruments with intonation adjustment capability as in the exemplary embodiment. 
     The cutout  46  is an open-ended rectangular cutout  46  located at the opposite end of the cavity  31  on the body module  17 , extending from the bridge  25  downwardly to the bottom end opening  21  of the body module  17 , and comprises a spring base plane  15 , two saddle mount planes  115 , and two knife-edge mounts  72 . The longitudinal length of the cutout  46  is configured in such a way that there is sufficient clearance between the lowest end of the attached tremolo system  60  and the flat surface when the assembled instrument is perpendicularly placed on a flat surface in the upright position. The transverse length of the cutout  46  is configured in such a way that the tremolo module  50  and hardtail  63  (as defined hereafter) can be attached to and removed from the body module  17  through the bottom end opening  21  of the body module  17 , and attached tremolo system  60  can be operated as intended without interference. 
     The spring base plane  15  is attached to the body module  17  with a bracket  24 . The bracket  24  includes two lateral rectangular planes, of which one laterally overlays the back plane of the bridge recess  28  between the mount bushings (not shown) of the bridge  25  and attached thereto with a plurality of wood screws (not shown), and another extends from the lowest edge of the bridge recess  28  and overlays a part of the uppermost wall  153  of the cutout  46  extending towards the back of the body module  17 . The spring base plane  15  is a lateral rectangular plate extending downwardly from the back edge of the bracket  24  and in parallel with the back surface plane of the body module  17 , and provides a static surface to hold the variable load applied to the tremolo system  60  via the compression springs  36  pushing the spring base plane  15  backward. The position of the spring base plane  15  can be adjusted by replacing it with another spring base plane  15  that provides the desired position of the spring base plane  15 , depending on the tension of the set of strings  130  being attached, or on the desired pivotally functional range of the tremolo system  60 . 
     Another embodiment may comprise one of the alternative position adjustment mechanisms, including without limitation one or a plurality of height adjustment shims in the dimensions of the spring base plane  15 , overlaying the front side surface of the spring base plane  15  and allowing for the adjustment of the position of the spring base plane  15  by the thickness or sum thereof without replacing the spring base plane  15 . 
     The saddle mount planes  115  of the exemplary embodiment are oblique rectangular planes facing downwardly and symmetrically disposed side to side on the side walls of the cutout  46  to provide two mounting surfaces for the saddle  114  in case of hardtail configuration ( FIG.  14   ) (as defined hereafter). The mounting surfaces of the saddle mount planes  115  are situated in such a diagonal way that allows for the saddle  114  to be removably and stably seated therein at the proximity of its outermost edges of the top surface of the crosswise segments  43  thoroughly in contact with the respective surfaces of the saddle mount planes  115 , and that the strings  130  running from the bridge  25  into the window  157  of the assembled instrument are mostly perpendicular to the top surface of the saddle  114 , and further that the strings  130  are running into the window  157  in the proximity of the medial points between the front side and back side of the body module  17  in order to achieve the desired break angle of the strings  130  at the bridge  25  and therefore to adjustably configure the saddle  114  into a secured position in the proximity of the aforementioned medial point. 
     The saddle mount planes  115  allow for the saddle  114  to be mounted in place as the respective mounting surfaces of the saddle mount planes  115  anchor the saddle  114  against the string tension pulling the saddle  114  towards the bridge  25 , and the saddle  114  is seated at the aforementioned medial point as the position achieves the possible shortest distance between the bridge grooves  27  of the bridge  25  and the string holes  135  of the machine tuners  82  across the mounting surfaces. The saddle mount planes  115  also allow for a moderate adjustment around the medial position by means of the friction between the counterfacing mounting surfaces. 
     Each of the saddle mount planes  115  comprises a knife-edge mount notch  71  situated symmetrically side-to-side thereon in the proximity of back side of the body module  17  to pivotally and removably accept the knife-edge tabs  73  of the tremolo module  50 . 
     The knife-edge mount notches  71  of the exemplary embodiment comprise an integrated cylindrical mounting shaft and a cylindrical base coaxially aligned. The cylindrical base comprises a V-shaped knife-edge mount notch  71  in the center of the bottom surface of the cylindrical base wherein the knife-edge tab  73  is seated to configure a fulcrum with minimal friction for the tremolo system  60 . The cylindrical mounting shaft and a cylindrical base are disposed perpendicularly to the saddle mount planes  115  in mounting cavities with a hole in the center thereof to accept the cylindrical shaft thereof. 
     The knife-edge mount notch  71  allows for the knife-edge tab  73  to be removably mounted in place as the knife-edge mount notch  71  anchors the knife-edge tab  73  against string tension pulling the knife-edge tab  73  towards the bridge  25 , so that the knife-edge  70  is automatically detached from the knife-edge mount notch  71  when the string tension is removed, and therefore the tremolo module  50  comprising is removed without any additional step, altogether with the compression springs  36 . 
     The neck module  20  of the exemplary embodiment comprises a fretboard  56  across the front side thereof, a plurality of frets  57  across the fretboard  56 , a truss rod (not shown) in a closed channel (not shown) underneath the fretboard  56 , a heel plane  66  at the lowest segment of the back of the neck module  20 , and a crown  44  at the uppermost segment of the neck module  20 . The neck module  20  further comprises a comb-shaped string anchoring apparatus  131  on the crown  44 , a string nut  99 , an axial fastener structure ( FIGS.  6 ,  7 ,  8 , and  9   ) on the heel plane  66 , and a plurality of recesses of string guides  134  between the string anchoring apparatus  131  and the string nut  99 . 
     The string anchoring apparatus  131  of the exemplary embodiment is a sheet of metal in the shape of a hair comb, and constitutes the uppermost end of the neck module  20 . The string anchoring apparatus  131  is secured with three wood screws  158  at the back of the crown  44 . The curved bottom end aligns with the perimeter of the crown  44  of the neck module  20 . The string anchoring apparatus comprises a pivotal edge  160  for a neck-end lever structure ( FIGS.  15 ,  16 ,  17   ) at the uppermost end, and the pivotal edge  160  of the string anchoring apparatus  131  comprises a plurality of string slots  138  aligned along the lateral edge. 
     The string slots  138  are an array of longitudinal open-ended slots positioned at comparable intervals to the intervals of the set of strings  130  at the string nut  99 , and are aligned with the corresponding string grooves  133  on the string nut  99 . The string slots  138  are cut in a way that allows the installation of the individual string  130  with a ball end  12  by anchoring the ball end  12  to the string slot  138  without the string retaining apparatus  137 . The longitudinal lengths of the string slots  138  are configured in a way that allows the lever tab  79  of the string retaining apparatus  137  to be attached and detached by overcoming the remaining tension of the strings  130  as has been pre-reduced by the machine tuners  82  in case of the hardtail configuration ( FIG.  14   ) (as defined hereafter), or by the tremolo system  60  after optionally being pre-reduced by machine tuners  82  in case of the full configuration ( FIG.  1   ) in the assembling and disassembling steps (as set out hereafter), and that the string retaining apparatus  137  is kept secured in position when the tremolo system  60  is operated to maximally reduce the string tension in the musical performance of the assembled instrument. 
     The string guides  134  are positioned between the string nut  99  and string slots  138  and aligned with the corresponding string slots  138  to set the break angle of the strings  130  at the string nut  99  as well as the angle between the string anchoring apparatus  131  and the strings  130  by holding the string  130  at a desired position. 
     In the exemplary embodiment, the string guides  134  are integrally configured as the longitudinal recesses on a part of the front wood surface of the crown  44 . 
     The string nut  99  is a nut generally available for, or mounted on the neck of non-portable conventional electric guitar instruments as aforesaid. The string nut  99  comprises the corresponding number of string grooves  133  to the strings  130  to be attached to the instrument to hold the strings  130  at defined positions at the uppermost end of the fretboard  56 . 
     The axial fastener structure ( FIGS.  6 ,  7 ,  8 , and  9   ) of the exemplary embodiment comprises a D-nut  49  and a thumb screw  33  to be engaged with the axial coupling structure ( FIGS.  6 ,  7 ,  8 , and  9   ) to removably secure the neck module  20  to the body module  17 . 
     The D-nut  49  is a nut with wood screw threads on the outside cylindrical surface. The D-nut  49  is disposed into a mounting hole at the defined medial position between the side edges of the heel plane  66  in such a manner that the back end of the D-nut  49  is flush with the heel plane  66  of the neck module  20 , or no part of the D-nut  49  is protruding from the heel plane  66 . The D-nut  49  is situated in such a position that the head of the thumb screw  33  is secured at the defined position in the central recessed plane  32 . The D-nut  49  preferably provides such a total surface area of helical threads contacting the wood of the neck module  20  that is comparable to such a total surface area of the threads of wood screws comprising the conventional bolt-on joint configurations. 
     The thumb screw  33  is a bolt with an oversized head  103  with knurled perimeter circumference allowing for sufficient fastening of the body module  17  and neck module  20  by manually rotating the oversized head  103  clockwise, and a conical shank  37 . The thumb screw  33  is adjustably disposed into the D-nut  49 . 
     The thumb screw  33  may be disposed into the D-nut  49  in two positions, comprising a fixed position wherein the thumb screw  33  is fully engaged to hold the adjustably static bond between the neck module  20  and the body module  17 , and a free-hanging position wherein the thumb screw  33  is attached to the D-nut  49  but allowing for the neck module  20  to be freely inserted or pulled out of the neck module  20 . Alternative embodiments may include a hexagonal hole for a generic hex key to be used in case of over-tightening of the thumb screw  33  causing difficulty in detaching the screw to disassemble the instrument. The conical shank  37  of the exemplary embodiment fits into the countersink  40  of the reinforcement plate  111  alongside the bolt slot  18 , securing the neck module  20  in a self-adjusted position. The dimensions of oversized head  103  are defined in such a way that the oversized head  103  can be rotated manually to achieve sufficient fastening of the neck module  20  and body module  17 , and that the oversized head  103  can be secured within the central recessed plane  32  and entirely or mostly flush with the back side surface of the body module  17  in the central recessed plane  32 . The length of the threaded section of the shaft of the thumb screw  33  is defined in such a way that the neck module  20  can be longitudinally inserted without interference into the neck pocket on the body module  17  in the free-hanging position, and that the conical shank  37  of the thumb screw  33  in the fixed position can be seated on the countersink  40  of the reinforcement plate  111  to secure the neck module  20  onto the body module  17 . 
     Another embodiment may include a thumb screw  33  the head of which comprises a clamping mechanism that may include a foldable lever into one or both of the bolt slot  18  or central recessed plane  32  to configure one or a plurality of flush surfaces with the back and other corresponding planes on the body module  17 , as the case may be, whereon any such feature is defined or configured. 
     The tremolo module  50  of the exemplary embodiment comprises a tremolo system  60 , a string retaining apparatus  137 , and a plurality of strings  130 . The tremolo module  50  provides the vibrato functionality comparable to a conventional synchronized tremolo system on the conventional electric guitars, and also facilitates the disassembling and reassembling steps of the instrument by providing a prompt removal and reinstallation of the entire or most of the string tension of the instrument. The string retaining apparatus  137  constitutes a neck-end lever structure ( FIGS.  15 ,  16 ,  17   ) together with the string anchoring apparatus  131  on the neck module  20 . 
     The tremolo system  60  comprises a lever  78 , a saddle  114 , a set of machine tuners  82 , and a whammy bar  13  to deliver the comparable pivotally leveraging functionality to conventional synchronized tremolo systems. More specifically, the tremolo system  60  normally stays in a position wherein the string tension of the strings  130  tuned at respectively defined tonal pitches and the counterbalance applied by the compression springs  36  are in balance. The tremolo system  60  is actuated by moving the whammy bar  13  into the body or away from the body by manually applied force to the whammy bar  13  to pivotally decrease or increase the length of the segment of the strings  130  between the string nut  99  and the saddle  114 , and thereby decrease or increase the string tension to modulate the tonal pitches for musical expressions including without limitation vibrato effect. The tremolo system  60  automatically resumes the balanced position after removing the manually applying force. The functionality is also utilized to facilitate the removing and reinstalling of the string tension when assembling or disassembling the instrument. 
     The lever  78  of the exemplary embodiment comprises a top plate member  144 , L-profile reinforcement beam member  110 , and two side wall members  122  symmetrically disposed side to side and connected at the lateral edges of the top plate member  144 , saddle mount tabs  116  symmetrically disposed side to side, a plurality of compression springs  36 , two knife-edge tabs  73  symmetrically disposed side to side, whammy bar  13 , and a bar mount  14  to removably attach a whammy bar  13  to manually operate the tremolo system  60  on the front side of the top plate member  144 . 
     The saddle mount tabs  116  at the lowest part of the lever  78  provide the planes to removably hold and secure the saddle  114  at the part of the upper surface of the crosswise segments  43  thereof with two mounting bolts  89  diagonally disposed through the saddle mounting holes on the saddle mount tabs  116 . 
     The compression springs  36  are secured on the back plane of the top plate member  144  with a fastening strip  53  which is secured to the top plate member  144  with the same number of bolts and nuts  19  as the springs. The bolts and nuts  19  are respectively disposed at the axial centers of the springs from the front side to the back side of the top plate member  144 . The compression springs  36  provide the counterbalancing force against the string tension and manually applied force of the actuated tremolo system  60 . While the front end of the compression springs  36  are fastened on the top plate member  144  with a fastening strip  53 , the back ends of the compression springs  36  are simply pressed down to the spring base plane  15  without any securing mean, and therefore further facilitates the removable attachment of the compression springs  36  to the instrument as part of the removable tremolo module  50 , compared to such one or a plurality of tension springs of the conventional synchronized tremolo system that are installed longitudinally across the body and most often require a plurality of tools and access from both front and back sides. 
     The top plate member  144  is the uppermost part of the lever  78  and holds the compression springs  36 . The lowest part of the top plate member  144  comprises an integrated L-profile reinforcement beam member  110  across two side wall members  122 . 
     The knife-edge tabs  73  are square-shaped tabs with the uppermost tapered edges, inclining forwardly and extending outwardly in the opposite transverse directions from the back bottom end of the sidewalls in the proximity of the saddle mount tabs  116 , and allow for the removable attachment to the knife-edge mount notches  71  attached to the saddle mount planes  115  of the body module  17 , configuring the fulcrum of the tremolo system  60  together with the knife-edge mount notches  71 . The uppermost tapered edges respectively have outer tapered edge segments and inner oblique edge segments towards the connected side wall members  122  to keep the clearance between the respective side wall members  122  of the lever  78  and the side walls of the cutout  46  of the assembled instrument to ensure the operation of the tremolo system  60  without interference with the side walls of the cutout  46 . The longitudinal length of the knife-edge tabs  73  is configured in such a way that the planes of the saddle mount tabs  116  are mostly in parallel with the saddle mount planes  115  when the instrument is assembled in the full configuration ( FIG.  1   ) and when the tremolo is not actuated, thereby allowing for sufficient clearance for the operation of the tremolo system  60  without any interference with the saddle mount planes  115 . The transverse length of the knife-edge tab  73  is configured in such a way that both of the knife-edge tabs  73  can be inserted into the corresponding knife-edge mount notches  71  without any interference, and that the non-oblique segments of the tapered edges occupies the majority of the transverse length of the knife-edge mount notches  71 . As aforementioned, the knife-edge tab  73  is anchored in the knife-edge mount notch  71  by means of the string tension pulling the tremolo system  60  towards the neck module  20  and the counterbalancing compression springs  36 , and therefore is automatically removed from the knife-edge mount notch  71  after removing part of the string tension with one or both of the set of machine tuners  82  and the tremolo system  60 . 
     The removable whammy bar  13  is a whammy bar generally available for the conventional synchronized tremolo systems, and attached to any such instrument with the threads on the mounting segment thereof. The whammy bar  13  provides the handle to manually operate the tremolo system  60  for the musical expressions or the disassembling and reassembling of the instrument as per the steps set out hereafter. 
     Preferably, the thickness of the round bar of the whammy bar  13  is sufficient to withstand the operational force during the disassembling and reassembling of the instrument. The exemplary embodiment comprises a generic 5 mm diameter whammy bar for the traditional synchronized tremolo systems. 
     The bar mount  14  is a cylindrical tube with threaded inner surfaces to accept the threaded mounting segment of the whammy bar  13  to be adjustably attached, and is perpendicularly attached onto the front side of the top plate member  144 , and secured at a defined position on the plate in the proximity of the one or the other lateral edges of the top plate member  144 , depending on the dominant hands of the instrumentalists, with a mounting bolt  161  disposed from the back side of the top plate member  144  into the threads of the bar mount  14 . The length of the mounting bolt  161  is configured in such a way that leaves a sufficient internally threaded segment of the tube for the mounting threads of the whammy bar  13 . 
     The saddle  114  in this exemplary embodiment is a rectangular piece of tone wood as is used for the body module  17  with a rectangular opening window  157  cut out in the center of the uppermost plane through the bottom plane thereof, framed by front and back lengthwise segments  77  in parallel and two crosswise segments  43  in parallel. The saddle  114  comprises a plurality of machine tuner mounting apertures  164  on the outermost surface of its two lengthwise segments  77  through to the window  157 , a couple of mounting nuts  93 , a couple of mounting channels  165 , and removable saddle mounting pins  118 . 
     The saddle  114  is removably attached to the lever  78  with a couple of mounting bolts  89  disposed through the saddle mount tabs  116  of the lever  78  and through a couple of mounting channels  165  extending at two corners of the saddle  114  into the corresponding mounting nuts  93  in the counterbores  166  on the opposite side of the saddle  114 . 
     The saddle  114  provides a capability to accept a wider variety of conventional electric guitar machine tuners for the purpose of tension adjustment at the bottom end opening  21  of the body module  17  on the saddle  114  both in the hardtail configuration ( FIG.  14   ) and the full configuration ( FIG.  1   ). 
     The instrument may be assembled without the lever  78  removably attached to the saddle  114 , with an alternatively arranged hardtail module  63  including the saddle  114 , a plurality of machine tuners  82 , a plurality of strings  130 , string retaining apparatus  137  and a couple of saddle mounting pins  118 . As aforementioned, the hardtail module  63  is attached on the saddle mount planes  115  of the body module  17  at the front surface of the crosswise segments  43  of the saddle  114  for the hardtail configuration ( FIG.  14   ) of the instrument. 
     In the hardtail configuration ( FIG.  14   ) of the exemplary embodiment, a couple of saddle mounting pins  118  protrude outwardly and symmetrically side to side from the respective pin mounting holes  167  on two lateral side surfaces of the saddle  114  in the opposite transverse directions alongside the front plane of the body module  17  of the assembled instrument in the hardtail configuration ( FIG.  14   ). The saddle mounting pins  118  are removably disposed into the respective mounting holes  167  to provide support to temporarily hold the saddle  114  in position when disassembling and reassembling the instrument, by suspending the saddle  114  from the front surface of the recumbently placed guitar into the cutout  46  thereof. 
     The machine tuner  82  is an independent machine tuner  82  generally available for the conventional electric guitar instruments including without limitation so-called in-line and three-per-side arrangements of machine tuner set on the headstock of any such instrument. The posts  108  of the set of machine tuners  82  must share an equal longitudinal length that allows the strings  130  to be held at the medial point between the front and back lengthwise frame of the window  157 , must be mountable on the saddle  114  free of any interference, and must be mountable into the mounting apertures (not shown) with or without shims as may be required. 
     Preferably, the machine tuners  82  are procured as a set for the in-line arrangement of conventional electric guitar instruments, and respectively have a couple of transverse string holes  135  for the strings  130 , and do not comprise a coaxial screw string clamping mechanism. Notwithstanding the foregoing, any such guitar machine tuner that meets the aforementioned required details can be used or can replace for rescue in case of emerging failure or repair. 
     The machine tuners  82  and their respective mounting apertures  164  are aligned and arranged on two lengthwise segments  77  of the saddle  114  in such a way that the machine tuners  82  are mounted alternating between the two lengthwise segments  77  of the saddle  114  from one crosswise segment  43  to the other crosswise segment  43  of the frame of the window  157 , and that the posts  108  of the machine tuners  82  protruding reciprocally from the lengthwise segments  77  of the saddle  114  into the window  157  are equally distanced from each other, and further that all of the buttons  30  of the set of machine tuners  82  are oriented downwards. For example, in the exemplary embodiment with a set of six machine tuners  82  from one crosswise segment  43  to another crosswise segment  43 , the posts  108  of the first, third, and fifth machine tuners  82  extend from one array on the front segment, and the posts  108  of the second, fourth, and sixth machine tuners  82  extend from another array on the back segment into the window  157 , with all of the buttons  30  of the set of machine tuners  82  oriented downwards. 
     Furthermore, the machine tuners  82  and their mounting apertures  164  are arranged in relation to their attached strings  130  in such a way that each of the attached strings  130  is held straight across the segment of the string  130  between the string nut  99  and the saddle  114  except for the break angle into a direction shared across the strings  130  at the bridge  25 , and that the attached strings  130  extend mostly perpendicularly into the window  157  at the medial points between the two lengthwise segments  77  of the saddle  114  when the tremolo system  60  is not actuated, or when the saddle  114  is removably attached without the lever  78 . 
     In the exemplary embodiment, the string retaining apparatus  137  is a piece of rectangular-shaped sheet metal, and comprises a bottom round curved edge in its assembled position, and a plurality of string apertures  2  for the corresponding number of strings  130 . The round curved edge is configured to be a lever tab  79 . The string retaining apparatus  137  is held in position on the string anchoring apparatus  131  by the tension of the strings  130  pulling the string retaining apparatus  137  into the locking position. The width of the string retaining apparatus  137  corresponds to the width of the string anchoring apparatus  131  on the neck module  20 . The longitudinal measurement of the string retaining apparatus  137  is less than the longitudinal measurement of the string anchoring apparatus  131 . 
     The string apertures  2  are arranged as an array of holes in the proximity of and in parallel with the transverse lateral edge of the string retaining apparatus  137 . The intervals between the string apertures  2  correspond to the intervals between the string slots  138  on the string anchoring apparatus  131  so that each string aperture  2  and corresponding string slot  138  closely align when the string retaining apparatus  137  with the strings  130  attached to the string anchoring apparatus  131 . The diameters of the string apertures  2  are configured in such a way that the aperture permits the corresponding string  130  in use to be inserted up to the ball end  12 , and that each string aperture  2  does not permit the ball end  12  to pass through, whereby the string retaining apparatus  137  is trapped between the ball ends  12  of the strings  130  and the machine tuners  82  of the disassembled tremolo module  50 , and the ball ends  12  are anchored at the back of the string retaining apparatus  137  of the assembled instrument. 
     The lever tab  79  facilitates the removable attachment of the string retaining apparatus  137  to the string anchoring apparatus  131  by radially leveraging the force manually applied to the lever tab  79  to overcome the remaining string tension after being decreased by turning the machine tuners  82  clockwise or counter-clockwise as the case may be, or pressing down the whammy bar  13 , or both in the steps set out hereafter. 
     The uppermost lateral edge of the string retaining apparatus  137  constitutes a lever edge  159  that slightly extends over the pivotal edge  160  of the string anchoring apparatus  131  in order to arrange a class-two lever configuration of the neck-end lever structure ( FIGS.  15 ,  16 ,  17   ) wherein the pivotal edge  160  of the string anchoring apparatus  131  functions as the pivotal fulcrum whereon the string retaining apparatus functions as a lever and radially pivots to leverage the manually applied force to the lever tab  79  to overcome any such remaining string tension as later described hereafter to rotate the array of anchored ball ends  12  at the back of the string retaining apparatus  137  over to the front side of the string anchoring apparatus  131 , and therefore to remove the strings  130  out of the string slots  138 . Likewise, when re-attaching the strings  130  with the string retaining apparatus  137  to the string anchoring apparatus  131 , the lever tab  79  is radially pressed down to the string anchoring apparatus  131  around the pivotal edge  160  in the same actively leveraged manner as aforementioned to overcome the increased string tension when the ball ends  12  are rotating from the front over to the back of the string anchoring apparatus  131  to snap the string retaining apparatus  137  on to the string anchoring apparatus  131 . 
     The string retaining apparatus  137  of the disassembled tremolo module  50  is trapped between the ball ends  12  of the strings  130  and the machine tuners  82  to help prevent the set of strings  130  from entangling or otherwise being damaged. 
     The set of strings  130  may be one of the various assorted sets of strings for the conventional electric guitars. Each string  130  comprises one ball end  12  on one end, and the other end thereof is attached in the same manner as the conventional electric guitars to the post  108  of the machine tuner  82  affixed to the saddle  114 , and through the corresponding string aperture  2  on the back side of the string retaining apparatus  137  whereon all the ball ends  12  of the strings  130  are anchored when the instrument is assembled. 
     The instrument of the present art allows for two attachment options for the strings  130  in respect of the string retaining apparatus  137  as aforementioned, including the attachment with the string retaining apparatus  137  and attachment without the string retaining apparatus  137 . The capability to attach the set of string  130  directly onto the string anchoring apparatus  131  without the string retaining apparatus  137  is enabled for the purpose of emerging situations wherein the string retaining apparatus  137  is lost, damaged or otherwise unavailable in order to provide additional resiliency for any such emerging situations without excluding any other intended purpose to remove and exclude the string retaining apparatus  137 . The instrument as assembled or disassembled without the string retaining apparatus  137 , however, does not provide any such functionality as enabled by the string retaining apparatus  137  as discussed hereinbefore. 
     The instrument of the present art further allows for two configuration options including the full configuration ( FIG.  1   ) with the tremolo module  50  and the hardtail configuration ( FIG.  14   ) with the hardtail module  63  that is arranged by removing and excluding the lever  78  of the tremolo system  60 . The hardtail configuration ( FIG.  14   ) option, unlike the options in respect of the string retaining apparatus  137 , may be proactively selected as a readily convertible option alternatively preferred by the instrumentalists. To convert the tremolo module  50  into the hardtail module  63  or to convert the hardtail module  63  to tremolo module  50 , the lever  78  of the tremolo module  50  may be detached or re-attached by removing or reinstalling the mounting bolts  89  of the saddle  114  respectively. However, as is the case of the string retaining apparatus  137 , the functionality enabled by the tremolo module  50  is removed together with the lever  78  in case of the hardtail configuration ( FIG.  14   ). 
     For both full configuration ( FIG.  1   ) and hardtail configuration ( FIG.  14   ), the neck module  20  is removably secured in position to the body module  17  with a thumb screw  33  extending from the back side of the body module  17  and through the bolt slot  18  and the reinforcement plate  111  at the end of the cavity  31  into the D-nut  49  of the neck module  20 , and with the roundheads  113  of the clamp screws  142  of the transverse clamping structure ( FIG.  5   ) disposed into the mounting holes at two deepest corners of the cavity  31 . 
     For the full configuration ( FIG.  1   ), the tremolo module  50  comprising a lever  78 , a saddle  114 , a string retaining apparatus  137  and a plurality of strings  130 , is removably attached to the body module  17  inside the cutout  46  with its knife-edge tabs  73  removably seated in the knife-edge mount notches  71  to configure a fulcrum that allows for addition and reduction of the string tension by pivotally operating the whammy bar  13 , and with the compression springs  36  pressing down on the spring base plane  15  to add the leveraged counterbalance against the string tension via the lever  78  and the configured fulcrum as aforementioned. The tremolo system  60  is kept in the pivotally operational position with the string tension upwardly pulling the tremolo system  60  towards the neck module  20  and the counterbalance applied by the compression springs  36 . The ball ends  12  of the strings  130  are anchored on the string apertures  2  at the back side of the string retaining apparatus  137  being attached on the string anchoring apparatus  131  at the crown  44  of the neck module  20  and is kept in place by the string tension pulling the strings  130  towards the body module  17  and therefore the strings  130  are pulled into the lowest ends of the string slots  138 , thereby pulling the string retaining apparatus  137  into the string anchoring apparatus  131  at a stable position. As is also the case of the conventional electric guitar instruments, the string tension allows for the strings  130  to be securely seated in the corresponding string grooves  133  of the string nut  99  and on the corresponding bridge grooves  27  of the bridge  25 . 
     For the hardtail configuration ( FIG.  14   ), the hardtail module  63 , comprising a saddle  114 , a string retaining apparatus  137  and a plurality of strings  130  excluding the lever  78  as well as compression springs  36  and the whammy bar  13 , is removably attached to the body module  17  inside the cutout  46  with its two crosswise segments  43  of the saddle  114  removably seated on the corresponding saddle mount planes  115  with the counterfacing surfaces optimally in contact with one another. The saddle  114  is kept in the aforementioned transverse position with the saddle  114  anchored by the saddle mount planes  115  as the string tension is pulling the saddle  114  upwardly towards the bridge  25 . The strings  130  and the string retaining apparatus  137  are configured to function on the string anchoring apparatus  131  in the same manner as in the full configuration ( FIG.  1   ). 
     For the full configuration ( FIG.  1   ), the steps to detach the tremolo module  50  from the assembled instrument comprise:
         An optional step to preliminarily remove such part of the string tension as may be required by rotating the buttons  30  of the machine tuners  82  clockwise or counter-clockwise as the case may be;   A step to press and hold the whammy bar  13  of the tremolo system  60  into the central part of the body module  17  to further remove an additional part of the string tension enough to operate the lever tab  79  of the string retaining apparatus  137 ;   A step to operate the lever tab  79  manually by radially turning the lever tab  79  around the pivotal edge  160  of the string anchoring apparatus  131  to overcome the remaining string tension and pry up to detach the string retaining apparatus  137  from the string anchoring apparatus  131 ; and   A step to pull the tremolo module  50  out of the cutout  46  of the body module  17  to remove the tremolo system  60 .       

     For the hardtail configuration ( FIG.  14   ), the steps to detach the hardtail module  63  from the assembled instrument comprise:
         A step to rotate the buttons  30  of the machine tuners  82  clockwise or counter-clockwise as the case may be to remove the string tension enough to operate the lever tab  79  of the string retaining apparatus  137 ;   A step to operate the lever tab  79  manually by radially turning the lever tab  79  around the uppermost edge of the string anchoring apparatus  131  to manually overcome the remaining string tension and pry up to detach the string retaining apparatus  137  from the string anchoring apparatus  131 ; and   A step to remove the hardtail module  63  from the cutout  46  of the body module  17 .       

     For both full configuration ( FIG.  1   ) and hardtail configuration ( FIG.  14   ), the steps to remove the neck module  20  from the instrument with the tremolo module  50  or hardtail module  63  previously removed comprise:
         A step to set the thumb screw  33  to the free-hanging position by rotating the thumb screw  33  counter-clockwise;   A step to pull up the neck module  20  in the longitudinal direction with the thumb screw  33  in the free-hanging position to unseat the neck module  20  from the clearance between the clamp screws  142  of the transverse clamping structure ( FIG.  5   ); and   A step to further pull up the neck module  20  in the longitudinal direction out of the cavity  31 .       

     For both full configuration ( FIG.  1   ) and hardtail configuration ( FIG.  14   ), the steps to attach or reattach the neck module  20  from the instrument with the tremolo module  50  or hardtail module  63  previously removed comprise:
         A step to longitudinally slide down the neck module  20  with the thumb screw  33  in the free-hanging position into the cavity  31  down to the transverse clamping structure ( FIG.  5   ) while at the same time inserting the attached thumb screw  33  into the bolt slot  18 ;   A step to press the neck module  20  fully down into the clearance between the clamp screws  142  of the transverse clamping structure ( FIG.  5   ); and   A step to set the thumb screw  33  into the fixed position by rotating the thumb screw  33  clockwise.       

     For the full configuration ( FIG.  1   ), the steps to attach or reattach the tremolo module  50  to the assembled body module  17  and neck module  20  comprise:
         A step to insert and hold the knife-edge tabs  73  into the corresponding knife-edge mount notches  71  from the cutout  46  of the body module  17  with the compression spring  36  placed on the spring base plane  15  while keeping the detached string retaining apparatus  137  in the proximity of the string anchoring apparatus  131  across the front side of the assembled body module  17  and neck module  20 ;   A step to press and hold down the whammy bar  13  of the tremolo module  50  into the central part of the body module  17  to reduce the length between the string anchoring apparatus  131  and the tremolo system  60 ;   A step to align the string retaining apparatus  137  with the string anchoring apparatus  131  and place the strings  130  into the corresponding string slots  138  of the string anchoring apparatus  131  by pressing down the lever tab  79  of the string retaining apparatus  137  from the front side to the back side of the string anchoring apparatus  131  while manually overcoming the string tension remained from the preceding detaching steps of the tremolo module  50  while holding down the whammy bar  13 ; and   A step to rotate the button  30  of each machine tuner  82  clockwise or counter-clockwise as the case may be for the same number of turn or turns as the preceding tremolo module  50  detaching steps, but in the opposite directions to add the tension required for each string  130  to be approximately in tune before disengaging the whammy bar  13 ; and   A step to fine-tune the strings  130  by rotating the machine tuners  82  clockwise or counter-clockwise as the case may be.       

     For the hardtail configuration ( FIG.  14   ), the steps to attach or reattach the hardtail module  63  to the assembled body module  17  and neck module  20  comprise:
         A step to place the saddle  114  onto two saddle mount planes  115  of the recumbently placed body module  17  to allow the saddle  114  to be suspended by two saddle mounting pins  118  supported by the front surface of the body module  17 ;   A step to align the string retaining apparatus  137  with the string anchoring apparatus  131  and place the strings  130  into the corresponding string slots  138  of the string anchoring apparatus  131  by operating the lever tab  79  of the string retaining apparatus  137  to manually overcome the remaining string tension from the preceding detaching steps of the hardtail module  63 ;   A step to rotate the button  30  of each machine tuner  82  clockwise or counter-clockwise as the case may be for the same number of turn or turns as the preceding hardtail module  63  detaching steps, but in the opposite directions to add the tension required for each string  130  to be in tune; and   A step to fine-tune the strings  130  by rotating the machine tuners  82  clockwise or counter-clockwise as the case may be.       

     For the full configuration ( FIG.  1   ) with the string retaining apparatus  137  excluded, the steps to detach the tremolo module  50  from the assembled instrument comprise:
         An optional step to preliminarily remove such part of the string tension as may be required by rotating the buttons  30  of the machine tuners  82  clockwise or counter-clockwise as the case may be;   A step to press and hold the whammy bar  13  of the tremolo system  60  into the central part of the body module  17  to further remove an additional part of the string tension enough to remove the ball ends  12  of the strings  130  from the string slots  138  of the string anchoring apparatus  131 ;   A step to pull the tremolo module  50  out of the cutout  46  of the body module  17  to remove the tremolo system  60 .       

     For the hardtail configuration ( FIG.  14   ) with the string retaining apparatus  137  excluded, the steps to detach the hardtail module  63  from the assembled instrument comprise:
         A step to rotate the buttons  30  of the machine tuners  82  clockwise or counter-clockwise as the case may be to remove the string tension enough to remove the ball ends  12  of the strings  130  from the string slots  138  of the string anchoring apparatus  131 ;   A step to remove the hardtail module  63  from the cutout  46  of the body module  17 .       

     For both full configuration ( FIG.  1   ) and hardtail configuration ( FIG.  14   ) with the string retaining apparatus  137  excluded, the steps to detach the neck module  20  from the instrument with the tremolo module  50  or hardtail module  63  previously removed comprise the same set of steps as for full configuration ( FIG.  1   ) and hardtail configuration ( FIG.  14   ) including the string retaining apparatus  137 . 
     For both full configuration ( FIG.  1   ) and hardtail configuration ( FIG.  14   ) with the string retaining apparatus  137  excluded, the steps to attach or reattach the neck module  20  to the body module  17  comprise the same set of steps as for full configuration ( FIG.  1   ) and hardtail configuration ( FIG.  14   ) including the string retaining apparatus  137 . 
     For the full configuration ( FIG.  1   ) with the string retaining apparatus  137  excluded, the steps to attach or reattach the tremolo module  50  to the assembled body module  17  and neck module  20  comprise:
         A step to insert and hold the knife-edge tabs  73  into the corresponding knife-edge mount notches  71  from the cutout  46  of the body module  17  with the compression spring  36  placed on the spring base plane  15  while keeping the detached ball ends  12  of the strings  130  in the proximity of the string anchoring apparatus  131  across the front side of the assembled body module  17  and neck module  20 ;   A step to press and hold down the whammy bar  13  of the tremolo module  50  into the central part of the body module  17  to reduce the length of the string  130  segment between the string anchoring apparatus  131  and the tremolo system  60 ;   A step to place the ball ends  12  of the strings  130  to corresponding string slots  138  of the string anchoring apparatus  131 ; and   A step to rotate the button of each machine tuner  82  clockwise or counter-clockwise as the case may be for the same number of turn or turns as the preceding detaching steps of the tremolo module  50 , but in the opposite direction to add the tension required for each string  130  to be approximately in tune before disengaging the whammy bar  13 ; and   A step to fine-tune the strings  130  by rotating the machine tuners  82  clockwise or counter-clockwise as the case may be.       

     For the hardtail configuration ( FIG.  14   ) with the string retaining apparatus  137  excluded, the steps to attach or reattach the hardtail module  63  to the assembled body module  17  and neck module  20  comprise:
         A step to place the saddle  114  onto two saddle mount planes  115  of the recumbently placed body module  17  to allow the saddle  114  to be suspended by two saddle mounting pins  118  and supported by the front surface of the body module  17 ;   A step to place the ball ends  12  of the strings  130  to corresponding string slots  138  of the string anchoring apparatus  131 ; and   A step to rotate the button  30  of each machine tuner  82  clockwise or counter-clockwise as the case may be for the same number of turn or turns as the preceding detaching steps of the hardtail module  63 , but in the opposite directions to add the tension required for each string  130  to be in tune; and   A step to fine-tune the strings  130  by rotating the machine tuners  82  clockwise or counter-clockwise as the case may be.       

     The principles and applications of the present invention have been set out herein with reference to a particular embodiment, provided that it is to be construed that the embodiment is merely for illustrative purposes, without limiting any other version as modified or rearranged of the exemplary embodiment as may be embodied within the spirit and scope of the present invention as defined by the appended claims.