Radio Shack MPA-50 manual

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Table of contents for the manual

  • Page 1

    Owner’s Manual Please read before using this equ ipment. MPA-50 40-Watt PA Amplifier 32-2002.fm Page 1 Friday, February 11, 2000 11:36 AM[...]

  • Page 2

    2 ˆ Contents Features ......... ................ ................ ................ ................. ................ ................ ......... 3 Preparation ....... ................ ................ ............. ................. ................ ................ ......... 4 Presetting th e Controls ................ ................. ..........[...]

  • Page 3

    3 Features ˆ Features Your RadioShack MPA-50 40- Watt PA Amplifier gives you 40 watts of solid power for your public address (PA) sys- tem. The built-in three-ba nd equalizer enables you to tailor the sound to fit your environment. Its wide frequ ency re- sponse easily handles amplification of voice and music. Its other featu res include: Built-In[...]

  • Page 4

    4 Preparation ˆ Preparation PRESETTING THE CONTROLS Warning: A sudde n high out put from the amplifier could dama ge your hearing or the speakers conn ected to the amplif i- er’s output. To avoid accidentally overdr iving a channel or premat urely amplifying an audio input, se t all the amplifier’s front- panel controls to their lowest set tin[...]

  • Page 5

    5 Making Connections ˆ Making Connections Important: Connect all auxiliary equipment and speakers before connecting pow er. PHONO L (Left) a nd R (Right) Input Jacks — Connect a turntable with a magnetic cart ridge. To avoid di stortion, do not connect a high-le vel audio input source to these jacks. Even th ough the amplifier has L and R input [...]

  • Page 6

    6 Speakers ˆ Speakers SPEAKER PHASING Phasing is the direction the sp eaker cone moves with re feren ce to the polari- ty of the con nection wires. Prope r phas- ing is import ant when you use mo re than one speaker in the same room or area. Out-of-phase spea kers can lose up to one-half of the ir potential volume , and can have a significantly de[...]

  • Page 7

    7 Speakers determine if your speakers ar e connect- ed in series, pa rallel, or series /parallel combined. Note: We recommend that you use speakers th at are rated the same (f or example, all 8- ohm speakers ) for all se- ries or parallel connections. • Speakers are co nnected in series when the first speaker’s positive ter- minal is connected [...]

  • Page 8

    8 Speakers One Speaker Connect the speaker ’s negative (– ) ter- minal to the amplifier’s COM (common) terminal. Th en connect the sp eaker’s positive (+) terminal to the amplifier’s terminal that matche s the speaker’s im- pedance. For example, if you have an 8 - ohm speaker, connect the speake r’s positive terminal to the amp lifier[...]

  • Page 9

    9 Speakers Speakers in Parall el 1. T o determine the total impedance of speakers connected in parallel, divide the impe dance of one speaker by the numbe r of speakers . For example, if you want to connect two 8-ohm speaker s in parallel, divide 8 (the impedance of one speaker) by 2 (the number of spea k- ers) for a total speaker imp edance of 4 o[...]

  • Page 10

    10 Speakers 4. T o determine the total impedance of speakers connected in serial and parallel combined, divide the imped- ance of one pair of speakers by the number of pairs. For example, if you want to co nnect four 8-ohm spea kers in serial and parallel combin ed, divide 16 (the impedance of one p air of speakers) by 2 (the number of sp eaker pai[...]

  • Page 11

    11 Speakers Cautions: • Before you connect th e speakers, be sure the total wat tage of the primary taps you intend to use do es not exceed the am plifier’s maximum 40-watt output power rating. • Avoid multiple connections to the amplifier ’s 70V an d COM terminals. Follow these ste ps to make the connections. 1. Connect a wire from th e am[...]

  • Page 12

    12 Controls and Operation ˆ Controls and Operation MICROPHONE 1 and 2 Inputs — Con- nect any standard d ynamic microphone with a 1 / 4 -inch plug. POWER Switch and Indicator — Press the bottom h alf of the switch to turn on the amplifier. The indicator lights. Press the top half of th e switch to turn o ff the amplifier. The indi cator goes of[...]

  • Page 13

    13 Troubleshooting ˆ T roubleshooting If you should ru n into difficulties, che ck the wiring of the system. Are the re any short circuits in th e speaker wirin g? Have you provided adequate ventila - tion? Did you calculate sp eaker imped- ance corr ectly? Be sure microphon es and connecting cables are not defective. Be sure you ar e using large [...]

  • Page 14

    14 Care ˆ Care To enjoy your MPA-50 40-Watt PA Am- plifier for a long time: • Keep the amplif ier dry . If it get s wet, wipe it dry immediately . • Use and store the amplifier only in normal temperature environments. • Han dle the amplifier gently and carefully . Don’t drop it. • Keep the amplifier away from dust and dirt. • Wipe the [...]

  • Page 15

    15 Specifications ˆ Specifications Output Power at 1 kHz, 10% THD ................. .............. ................ .............. .............. .... 40 W atts Power Bandwidth at 1W , 10% THD, Auxiliary Input ............................................ 70 Hz–20 kHz THD at 2W , 1 kHz MIC1 .......... ........... .............. .............. ...[...]

  • Page 16

    32-2002 81 108 1780C 02A00 Printed in China RadioShack A Division of Ta ndy Corporation Fort Worth, Texas 76102 Limited One-Y ear Warranty This product is warranted by RadioShack against manufactu ring defects in material and workman- ship under normal use for one (1 ) year from t he da te of pu rchase from Radi oSha ck compan y- owned stores and a[...]