RadioShack MPA-125 - Manual

Page 2 - Contents

2 ˆ Contents Features .................................................................................................................................. 3 Preparation ............................................................................................................................. 4 Prese...

Page 3 - Features; Your amplifier includes these features:; CAUTION

3 Features ˆ Features Your RadioShack MPA-125 100-Watt PAAmplifier gives you the versatility and poweryou need in a professional sound system. Itswide frequency response easily handles am-plification of voice and music. Use it in meet-ing halls and auditoriums, at sports events, inschools, and in th...

Page 4 - Preparation; PRESETTING THE CONTROLS; Presetting Audio Input Devices; Set the audio input sources’ controls to these levels:; Presetting the Amplifier; Set the amplifier’s controls to these levels:

4 Preparation ˆ Preparation PRESETTING THE CONTROLS Before you begin making connections or using your amplifier, preset the audio input source’sand the amplifier’s controls to avoid over-driving a channel or producing sudden unexpectedloud sounds. Presetting Audio Input Devices Set the audio input s...

Page 5 - MOUNTING THE AMPLIFIER; Connections; CONNECTING INPUT SOURCES; Before you make any connections, be sure; on the front of the amplifier is out and the; Connecting Microphones; and unbalanced jack. You need a microphone cord with a

5 Connections MOUNTING THE AMPLIFIER You can mount the amplifier in a standard-sized audio equipment rack or on a desk,shelf, or table. Be sure you place it in a loca-tion with adequate ventilation. Do not put iton thick carpeting (which can restrict air flow)or near a heat source such as a heat ven...

Page 6 - Connecting a Turntable

6 Connections Notes: • If your microphone’s cord is longer than 20 feet (6.01 meters), we recommend that you connect it to a balanced jack to reduce signal hum. • If you connect a microphone to both jacks for MIC 1 , MIC 2 , MIC 3 , or MIC 4 , the microphone you connect to the unbalanced jack has pr...

Page 7 - Connecting an Auxiliary Sound Source; jack on the back of the amplifier.; Connecting the MIX BUS Jack; Connecting an Equalizer; and; jacks; Note: You can also connect a tape deck to the

7 Connections Connecting an Auxiliary Sound Source You can connect any high-level sound source, such as a CD player, tape deck, or tuner, to the CD/AUX jack on the back of the amplifier. Connecting the MIX BUS Jack You can connect another MPA-125 to this jack to double the size of your PA system. Th...

Page 8 - • Speakers are connected in series when

8 Connections CONNECTING THE SPEAKERS You can connect one or more 4-, 8- or 16-ohm speakers to the amplifier, with or with-out transformers. To ensure equal volumefrom each speaker, all connected speakersshould have the same impedance rating. Proper phasing is important when you usemore than one spe...

Page 9 - Preparing the Speaker Wire

9 Connections You can achieve a proper total impedanceby combining series and parallel connec-tions. Preparing the Speaker Wire Use the shortest length of wire possible toconnect the speakers. After placing thespeakers, use this table to determine thewire length and choose the appropriategauge size:...

Page 10 - Connecting Two Speakers In Parallel; Connecting Four Speakers In Series/Parallel Combination

10 Connections Connecting Two Speakers In Parallel Follow these steps to connect speakers in parallel. 1. Connect both speaker’s negative (–) terminals to each other, then connect both wires to the COM terminal on the back of the amplifier. 2. Connect both speaker’s positive (+) terminals to each ot...

Page 12 - CONNECTING POWER

12 Connections Follow these steps to connect speakers using a transformer. Connect a wire from 70V RMS on the back of the amplifier to the transformer’s desired pri-mary tap (10, 5, 2.5, 1.25 or 0.62 watts). Note: Usually, each speaker in a systemuses the same wattage tap. If you want aparticular sp...

Page 13 - SAFETY INDICATORS; Listening Safely; USING AN EQUALIZER

13 Connections SAFETY INDICATORS Your amplifier has two indicators that warn you of potential damage to the amplifier. The CLIPPING indicator lights when a sound source’s signal exceeds its mixing control setting.If this happens, reduce the level of the appropriate mixing control or reduce MASTER VO...

Page 14 - USING THE FEEDBACK FILTER; The; After you adjust; clockwise until you reduce or eliminate the feedback.; control decreases feedback frequencies by up to 12 dB. If it does

14 Connections USING THE FEEDBACK FILTER The FEEDBACK FILTER control lets you reduce or eliminate squeal and other noise caused by feedback. After you adjust MASTER VOLUME , MIC 1 , MIC 2 , MIC 3 , MIC 4/PHONO , and CD/AUX , turn on the amplifier and any connected sound source. If you hear any feedb...

Page 15 - Troubleshooting

15 Troubleshooting ˆ Troubleshooting We do not expect you to have any problems with your RadioShack MPA-125 100-Watt PA Am-plifier, but if you do have a problem, this chart might help. If not, take the amplifier to your localRadioShack store for assistance. Symptom Possible Cause Suggestion No power...

Page 16 - Care and Maintenance

16 Care and Maintenance ˆ Care and Maintenance Your RadioShack MPA-125 100-Watt PA Amplifier is an example of superior design andcraftsmanship. The following suggestions will help you care for your amplifier so you can en-joy it for years. Keep the amplifier dry. If it gets wet, wipe it dry immediat...

Page 17 - REPLACING THE FUSE

17 Care and Maintenance REPLACING THE FUSE If the amplifier does not operate, you mightneed to replace the fuse on the back of theamplifier with the supplied (or another) 3-amp, 250-volt fuse. Important: Let the amplifier cool down andsee if it starts again before you assume afuse needs to be replac...

Page 18 - Specifications

18 Specifications ˆ Specifications Output Power at THD 2%, 8 Ohm Load 1 kHz ................................................................................... 100 W Total Harmonic Distortion (at 70 Watts, 8 ohms, 1 kHz, with Band Pass Filter) MIC (Phone Jack) ..........................................

Page 19 - Notes

19 Notes ˆ Notes 32-2003.fm Page 19 Tuesday, March 28, 2000 10:45 AM

Page 20 - Limited One-Year Warranty; We Service What We Sell

32-2003 03A00 Printed in China RadioShackA Division of Tandy CorporationFort 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 RadioShack com...

RadioShack MPA-125 - Manual

Table of Contents:

Summary

Other RadioShack Models