[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-640327-105":59,"doc-detail-640327-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","20-watt-acmobile-pa-amplifier-owners-manual","20-Watt AC/Mobile PA Amplifier - Owners Manual","","Owners manual for the Radio Shack MPA-31 MPA-3120 20-watt AC/mobile PA amplifier. It explains the equipment purpose, available inputs and outputs, and key setup steps before operation. Guidance covers placing the amplifier with adequate ventilation, presetting control levels for safe startup, connecting microphones, turntables (PHONO) and auxiliary audio sources (AUX/CD), and speaker placement and wiring requirements. Includes warnings about electrical shock, hearing risk, and correct speaker impedance and phasing.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":30,"@type":76,"position":81},"https://docshare.wps.com/document/technology/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/20-watt-acmobile-pa-amplifier-owners-manual/640327/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/20-watt-acmobile-pa-amplifier-owners-manual/640327.png","ImageObject",300,407,{"name":92,"@type":93},"AditGamingID","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-26","2026-10-22",true,{"@type":102,"interactionType":103,"userInteractionCount":14},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What power options does the MPA-31 amplifier support?","Question",{"text":112,"@type":113},"It operates on either 120 volts AC or 12 volts DC, allowing use in varied venues.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How should input controls be set before connecting sources?",{"text":117,"@type":113},"Set the controls to the preset levels shown in the manual (e.g., POWER Off; MIC 1/MIC 2/PHONO-AUX-CD to MIN; TONE to MD; MASTER VOLUME to 0) before connecting outputs to the amplifier inputs.",{"name":119,"@type":110,"acceptedAnswer":120},"What wiring and impedance guidance is given for connecting speakers?",{"text":121,"@type":113},"Connect speakers with the same impedance rating for equal volume, use appropriate wire gauge based on wire length, and follow proper speaker phasing so coverage sounds correct when using multiple speakers.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},640327,1793030841,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":29,"category_name":30,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":14,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":46,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":143,"read_time":31},962094249103,"https://ap-avatar.wpscdn.com/davatar_276721f389ce27ea32af1340a28f341c","Please read before using this equipment.  \nMPA-31  \n# 20-Watt AC/Mobile PA Amplifier\n\nYour new Radio Shack MPA-3120-Watt AC/Mobile PA Amplifier gives you20 Watts of solid power for your PAsystem.Its wide frequency responseeasily handles ampification of voice andmusic.It operates on either 120 voltsAC or 12 volts DC power so you canuse it in meeting hals and auditoriums,at sports evets,in schools,in the officefor paging systems—anywhere youneed to deliver special anmnouncementswith great sound.  \nIt includes the followng features:  \nMicrophone lrput Jacks—let you con-nect up to two microphanes.  \nAuxiliary input Jacks—lets you con-nect a variety of audio input sources formusic and special effects.  \n70-Voit Line Output -lets you con-nect line transfomers for a muttiple-speaker PA system.  \nMaster Voume Control—lets you ad-just the overall sound level.  \nTONE Contrdl—lets you customizethe tone of the sound to suit your per-sonal preferences depending on theacoustics,speakers,and sound source.  \nRead this manual carefully.It describesvarious speaker connections to help youselect the best arrangement for yoursystem and also explains how to usethe ampifier..  \nThe seral number is on the amplifier'sback panel.For your pemanert rec-ords,we recommend you record it be-low.  \nSerial Number.            \nWAFNBNG:TO REDLCE THE RSK OF ·FFE OR日ECTRC SHOCK,DO.NOT EXPOSE THS AMPU-FER TO RAN CR MOSTURE  \nThis symbol is intended to alert you thatdangerous urinsuated votage wilin theprocuct's encosre might be of sufficientmagritude to corstitte a sk of electicshock.Do not open the product's case.  \nThis symbol is intended to infom you of im-portant operating and maintenance(servic-ng)nstuctions in the papers accompanry-ng this product.  \n## Setting the Amplifier\n\nSetting the Input Sources  \nTo avoid sudden audio from the inputsources,set their controls to the levelsshown below before you connect theiroutput jacks to the amplifier's inputjacks.  \n## PREPARATION               \n\nPLACING THE AMPLIFIER  \nBefore you use your ampfifier,be sure you choose a location with adequate ventila-tion.Do not place the amplifier on thick carpeting(which can restrict the air flow)ornear a heat source,such as a heat vent or radiator (which can cause the amplifier tooverheat).  \n## PRESETTING THE CONTROLS\n\n\n| Control   | Setting   |\n| --- | --- |\n| POWER   | Off   |\n| MIC 1,MIC 2,PHONO/AUX.CD   | MIN   |\n| TONE   | MD   |\n| MASTER VOLUME   | 0   |\n\nWarning A sudden high output fromthe amplifier could damage your hearingor the speakers connected to the ampli-fier's output.  \nTo avaid accidentatly overdriving a chan-nel or prematurely amplifying an audioinput,set the ampifier's contros to thelevels shown below before you connectthe AC power cord or tum on power.  \n| Audlo Device   | Control   | Setting   |\n| --- | --- | --- |\n| Turntable   | Power   | Off   |\n| Tape Deck   | Power   | Off   |\n| CD Player   | Power   | Off   |\n| Amplifier/Receiver   | Power  \u003Cbr>Tone   | Off  \u003Cbr>Flat   |\n\n## CONNECTING AUDIOCOMPONENTSTO THE AMPLIFIER\n\nYou can connect optional components(such as microphones,tuners,tumta-bles,or CD players)to your amplifier toexpand your system.Your local RadioShack store caries a wide selection ofaudio components,adapters,micro-phones,and speakers.  \nCaution:Make sure you make all theconnections to the amplifier and speak-ers before connecting and tuming onpower.  \n## Connecting Microphones\n\nYou can connect a microphone to oneor both of the amplifier's MC 1 andMIC 2 input jacks.The microphone(s)can be high-or low-impedance andmust have a 1/4-inch plug.  \n## Connecting a Turntable\n\nYou can connect an audio input source,such as a magnetic cartridge tuntableto the amplifier's PHONO jack.  \nCaution:Do not connect a high levelaudio input source,such as a ceramiccartridge tumtable,to the PHONOinput jack.Doing so could cause sounddistortion.  \nGROUND WIRE  \n## Notes:\n\n● To avoid a low frequency hum,con-nect your tuntable's ground wire(usually black or green)to","cbCaio81PzZb1BhD","https://ap.wps.com/l/cbCaio81PzZb1BhD","pdf",554087,"English","# Setting the Amplifier\n## Setting the Input Sources\n## Preparation\n### Placing the Amplifier\n## Presetting the Controls\n# Connecting Audio Components to the Amplifier\n## Connecting Microphones\n## Connecting a Turntable\n## Notes\n## Connecting an Auxiliary Audio Source\n# Placing the Speakers\n# Connecting the Speakers","[{\"question\":\"What power options does the MPA-31 amplifier support?\",\"answer\":\"It operates on either 120 volts AC or 12 volts DC, allowing use in varied venues.\"},{\"question\":\"How should input controls be set before connecting sources?\",\"answer\":\"Set the controls to the preset levels shown in the manual (e.g., POWER Off; MIC 1/MIC 2/PHONO-AUX-CD to MIN; TONE to MD; MASTER VOLUME to 0) before connecting outputs to the amplifier inputs.\"},{\"question\":\"What wiring and impedance guidance is given for connecting speakers?\",\"answer\":\"Connect speakers with the same impedance rating for equal volume, use appropriate wire gauge based on wire length, and follow proper speaker phasing so coverage sounds correct when using multiple speakers.\"}]","20-Watt AC/Mobile PA Amplifier - Owners Manual | PDF",1792708585]