Radio Shack MPA-50 Owner's Manual - Features

Manual is about: 40-Watt PA Amplifier

Summary of MPA-50

  • Page 1

    Owner’s manual please read before using this equipment. Mpa-50 40-watt pa amplifier 32-20 02.Fm page 1 fr id ay, februar y 11, 2000 11: 36 am.

  • Page 2: Contents

    2 ˆ contents features ................................................................................................................... 3 preparation .............................................................................................................. 4 presetting the controls ..............

  • Page 3: Features

    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-band equalizer enables you to tailor the sound to fit your environment. Its wide frequency re- sponse easily handles amplification of voice an...

  • Page 4: Preparation

    4 preparation ˆ preparation presetting the controls warning: a sudden high output from the amplifier could damage your hearing or the speakers connected to the amplifi- er’s output. To avoid accidentally overdriving a channel or prematurely amplifying an audio input, set all the amplifier’s front- p...

  • Page 5: Making Connections

    5 making connections ˆ making connections important: connect all auxiliary equipment and speakers before connecting power. Phono l (left) and r (right) input jacks — connect a turntable with a magnetic cartridge. To avoid distortion, do not connect a high-level audio input source to these jacks. Eve...

  • Page 6: Speakers

    6 speakers ˆ speakers speaker phasing phasing is the direction the speaker cone moves with reference to the polari- ty of the connection wires. Proper phas- ing is important when you use more than one speaker in the same room or area. Out-of-phase speakers can lose up to one-half of their potential ...

  • Page 7

    7 speakers determine if your speakers are connect- ed in series, parallel, or series/parallel combined. Note: we recommend that you use speakers that are rated the same (for example, all 8-ohm speakers) for all se- ries or parallel connections. • speakers are connected in series when the first speak...

  • Page 8

    8 speakers one speaker connect the speaker’s negative (–) ter- minal to the amplifier’s com (common) terminal. Then connect the speaker’s positive (+) terminal to the amplifier’s terminal that matches the speaker’s im- pedance. For example, if you have an 8- ohm speaker, connect the speaker’s positi...

  • Page 9

    9 speakers speakers in parallel 1. To determine the total impedance of speakers connected in parallel, divide the impedance of one speaker by the number of speakers. For example, if you want to connect two 8-ohm speakers in parallel, divide 8 (the impedance of one speaker) by 2 (the number of speak-...

  • Page 10

    10 speakers 4. To 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 connect four 8-ohm speakers in serial and parallel combined, divide 16 (the impedance of one pair ...

  • Page 11

    11 speakers cautions: • before you connect the speakers, be sure the total wattage of the primary taps you intend to use does not exceed the amplifier’s maximum 40-watt output power rating. • avoid multiple connections to the amplifier’s 70v and com terminals. Follow these steps to make the connecti...

  • Page 12: Controls and Operation

    12 controls and operation ˆ controls and operation microphone 1 and 2 inputs — con- nect any standard dynamic microphone with a 1 / 4 -inch plug. Power switch and indicator — press the bottom half of the switch to turn on the amplifier. The indicator lights. Press the top half of the switch to turn ...

  • Page 13: Troubleshooting

    13 troubleshooting ˆ troubleshooting if you should run into difficulties, check the wiring of the system. Are there any short circuits in the speaker wiring? Have you provided adequate ventila- tion? Did you calculate speaker imped- ance correctly? Be sure microphones and connecting cables are not d...

  • Page 14: Care

    14 care ˆ care to enjoy your mpa-50 40-watt pa am- plifier for a long time: • keep the amplifier dry. If it gets wet, wipe it dry immediately. • use and store the amplifier only in normal temperature environments. • handle the amplifier gently and carefully. Don’t drop it. • keep the amplifier away ...

  • Page 15: Specifications

    15 specifications ˆ specifications output power at 1 khz, 10% thd ............................................................................... 40 watts power bandwidth at 1w, 10% thd, auxiliary input ............................................ 70 hz–20 khz thd at 2w, 1 khz mic1 ....................

  • Page 16

    32-2002 811081780c 02a00 printed in china radioshack a division of tandy corporation fort worth, texas 76102 limited one-year warranty this product is warranted by radioshack against manufacturing defects in material and workman- ship under normal use for one (1) year from the date of purchase from ...