text: the present invention is directed to a computer installed stereo pa amplifier card . with respect to fig1 , what is shown is the parts list for the device . the parts list ( 10 ) contains information about the parts , including the following : name / designation number , their value , package type and manufacturer part number . this information is used for the ordering of the components and parts . the designation number also gives the location where the components and parts go on the printed circuit boards . of course , those skilled in the art will appreciate that various other components could be used to produce the present invention . this parts list is , therefore , provided as an example and illustrative of the preferences of the inventors . by using other components , such as , thru hole components , the present invention could also be produced . alternatively to the printed circuit boards , other types of boards may be used , such as , perforated boards or prototyping boards . connections to the board , such as input , output , and / or power could be hard - wired to the board . by knowing the components and their values , certain substitutions might therefore be made as long as the parameters that make this device unique are maintained . with respect to fig2 , what is shown are the various components . components such as the i . c . chip ( 40 ), chip resistor ( 41 ), chip capacitor ( 42 ), electrolytic capacitor ( 43 ), chip led ( 44 ), and parts , the ferrite bead ( 90 ), the four pin header ( 165 ), the stereo mini jack ( 50 ), male db9 ( 184 ), female db9 ( 185 ) and the four position screw terminal strip ( 80 ) are all parts for the assembly of the p . a . amplifier and speaker connector boards . with respect to fig3 , what is shown are the blank printed circuit boards . the blank p . a . amplifier board ( 100 ) and the speaker connector board ( 110 ) have been drilled , etched , plated and silk screened . they each have components and part designators and are ready to be assembled . with respect to fig4 , what is shown is an assembled version of the present invention . with the components , i . c . chip ( 40 ), chip resistor ( 41 ), chip capacitor ( 42 ), electrolytic capacitor ( 43 ), chip led ( 44 ), and the four pin header ( 165 ) disposed on an amplifier board ( 100 ). also shown are the male db9 ( 184 ), female db9 ( 185 ) and the four position screw terminal strip ( 80 ), which are preferably soldered in place onto the speaker connection board ( 130 ). stand off screws ( 75 ) are preferable to attach the device ( 120 ) to the computer bracket ( 70 ), as is at least one stereo mini jack ( 174 ). the stand off screws ( 75 ) may , however , be replaced by any fastener or clip that locks the device ( 120 ) to the bracket ( 70 ). the computer bracket ( 70 ) allows for the securing the device at the computers card slot opening . the header ( 165 ) is used for the power supply connection . the stereo mini jack ( 174 ) is used for the audio line input . the female db9 ( 185 ) outputs the amplified audio and is where the speaker connector board ( 130 ) is attached . the arrows indicate the speaker connector board &# 39 ; s attachment to the present invention ( 120 ). the male db9 ( 184 ) on the speaker connector board ( 130 ) plugs into the female db9 connector ( 185 ) of the present invention ( 120 ). the speaker wires are connected to the four position terminal screw strip ( 80 ) observing the polarity : + left , gnd , gnd , + right . the speaker connector board ( 130 ) allows for the connection of speakers to the present invention ( 120 ). of course those skilled in the art will appreciate that various other connectors could be used to produce the present invention . those connectors therefore , are provided as an example and illustrative of the preference of the present inventors . with respect to fig5 , what is shown is the assembled invention ( 120 ) installed inside a computer ( 140 ). the screw ( 155 ), of the computer &# 39 ; s case , secures the assembled invention ( 120 ) in an open card slot of the computer by means of the computer bracket ( 70 ). the computer &# 39 ; s power supply cable ( 160 ) is connected to the four pin header ( 165 ) on the present invention ( 120 ). with respect to fig6 , what is shown is the speaker connector board assembled . with the db9 ( 184 ) and the four position screw terminal strip ( 80 ) soldered in place . the speaker connector board ( 130 ) is ready to be attached to the present invention . the speaker wires are also connected to the speaker connector board ( 130 ) at the four position screw terminal strip ( 80 ). with respect to fig7 , what is shown is the back of the computer with the present invention completely installed . the computer ( 140 ) is shown with its side panel ( 150 ) intact and ac power cord ( 145 ). it has the speaker connector board ( 130 ) attached at the computer bracket ( 70 ) of the present invention ( 120 ), the hidden view of which is shown by dashed lines on the inside of the computer ( 140 ). the speaker wires ( 175 ) are connected at the four position screw terminal strip ( 80 ). the ferrite bead ( 90 ) is placed around all four speaker wires ( 175 ) next to the speaker connector board ( 130 ). the stereo mini cable ( 170 ) is then used to connect the computer &# 39 ; s line output ( 173 ) to the line input of the present invention at the stereo mini jack ( 174 ). the power supply connector ( 160 ) provides power . with respect to fig8 , what is shown is a typical computer &# 39 ; s volume control . the master or main volume control of the computer system and its input volume levels are controlled via the computer &# 39 ; s volume control applet ( 200 ). by adjusting the sliders and turning on or off the mute buttons the amplified audio levels are achieved . the master or main volume control has system audio output level control . with respect to fig9 , what is shown is one particular version of a circuit diagram descriptive of the present invention . the circuit diagram ( 220 ) shows the components , their values and electrical connections . it also shows the signal processing that occurs from the input to the output for left and right channels ( stereo ) and shows the power supply voltages used . also shown are the three different sets of components for the two thru hole circuits and the one surface mount circuit . it should be appreciated by those of skill in the art that this particular circuit diagram is but one example of the circuitry that can be employed to implement the present invention . it is certainly possible to otherwise structure the circuit with variations in the components so as to produce the equivalent or substantially equivalent design . such equivalent and substantially equivalent designs are intended to be and in fact are within the scope of this disclosure and with the scope of the present invention . with respect to making the present invention , the most preferable way is by assembling the parts on list ( 10 ) with a soldering iron and solder . the assembly is done by soldering or connecting the parts , ic chip ( 40 ), chip resistor ( 41 ), chip capacitor ( 42 ), electrolytic capacitor ( 43 ), chip led ( 44 ), jack ( 50 ), header ( 165 ), screw terminal strip ( 80 ), db9 connectors ( 184 , 185 ), and the ferrite bead ( 90 ) to the designated location on both the amplifier circuit board ( 100 ), and the speaker connector board ( 110 ). the computer bracket ( 70 ) is then secured in place with standoff screws ( 75 ). the completed amplifier board ( 120 ) is then installed into the computer ( 140 ) and the speaker connector board ( 130 ) is attached at the computer bracket ( 70 ) via the db9 connection ( 184 , 185 ) to the present invention ( 120 ). ( see fig4 ) alternatively the present invention could also be assembled by using a perforated board or prototyping board , wire , thru hole components and parts . by following a circuit diagram and soldering the wires in place , a working p . a . amplifier circuit would be constructed . other methods for input , output and / or power , may be used such as , bare wire or different types of connectors . a board wired in this manner would eliminate the computer bracket ( 70 ) and the speaker connector board ( 130 ) and could be free standing and able to reside in any location where its connections did not short out . installation is accomplished by powering down the computer ( 140 ), unplugging the ac power cord ( 145 ) and removing the cover ( 150 ). insert the device ( 120 ) into an open card slot and secure with a screw ( 155 ). plug the computer &# 39 ; s power supply cable ( 160 ) in to the device &# 39 ; s 4 pin header ( 165 ) observing the polarity of the 12 volt supply . replace the cover ( 150 ), plug in the ac power cord ( 145 ) and connect the stereo mini cable ( 170 ) from the computer &# 39 ; s line out ( 173 ) to the audio input connector ( 174 ) of the device ( 120 ). connect the speaker wires ( 175 ) to the 4 position screw terminal strip ( 80 ) of the speaker connector board ( 130 ) observing the polarity (+ left , grd , grd , + right ). place the ferrite bead ( 90 ) around the two pairs of speaker wires ( 175 ) next to the speaker connector board ( 130 ) and plug the db9 male ( 184 ) of the speaker connector board ( 130 ) into the db9 female connector ( 185 ) of the device ( 120 ). power up the computer and use the computers volume control ( 200 ) to adjust the volume level . it is preferable for the present invention to be manufactured using the latest assembly technology in circuit board construction i . e . hole drilling , installation of surface mount parts , and physical assembly by a certified electronic assembly house to assure quality control . to install the present invention , power down the computer , unplug the ac cord and remove the cover . insert the device into an open card slot and secure the bracket in place with a screw . plug the 12 volt power supply cable from the computer &# 39 ; s power buss into the amp board &# 39 ; s 4 - pin header observing the polarity of the power supply . replace the cover , plug in the ac cord and plug the stereo mini cable from the computer &# 39 ; s audio line output to the audio input connector of the device . connect the speaker wires to the 4 position screw terminal strip observing the polarity (+ left , grd , grd , + right ). place the ferrite bead around the two pairs of speaker cables next to the speaker connector board and plug it into the db9 connector of the device . power up the computer and use the computer &# 39 ; s volume controls ( 200 ) to adjust the volume level . with the audio amplifier installed and the computer powered up the user is able to open a program for playing audio cds , dvd &# 39 ; s , and / or a various types of presentations while selecting the appropriate input is the computer is supporting which applies to the user &# 39 ; s needs . with an audio source playing , the output level to the speakers is adjusted by opening the computer &# 39 ; s volume control ( 200 ) and adjusting the main volume level as well as the input levels . while the present invention has been described above in terms of specific embodiments , it is to be understood that the invention is not limited to these disclosed embodiments . many modifications and other embodiments of the invention will come to mind of those skilled in the art to which this invention pertains , and which are intended to be and are covered by both this disclosure and the appended claims . it is indeed intended that the scope of the invention should be determined by proper interpretation and construction of the appended claims and their legal equivalents , as understood by those of skill in the art relying upon the disclosure in this specification and the attached drawings .