RadioShack MPA-40 - Manuals

Page 2 - Contents

2 ˆ Contents Features ................................................................................................................... 3 Preparation .............................................................................................................. 4 Presetting the Controls ..............

Page 3 - Features

3 ˆ Features Your RadioShack 20-Watt PA Amplifiergives you 20 watts of solid power foryour PA system. Its wide frequency re-sponse easily handles amplification ofvoice and music. It operates on either120 volts AC or 12 volts DC power soyou can use it anywhere you want to de-liver special announcemen...

Page 4 - Preparation; CHOOSING A LOCATION; Making Connections

4 ˆ Preparation PRESETTING THE CONTROLS Warning: A sudden high output from theamplifier could damage your hearing orthe speakers connected to the amplifi-er’s output. To avoid accidentally overdriving achannel or prematurely amplifying anaudio input, set all the amplifier’s front-panel controls to t...

Page 5 - Speakers; SPEAKER PHASING

5 PHONO/AUX/CD Switch — select theinput source. Even if you connectedauxiliary equipment to both the PHONO and AUX/CD input jacks, you can use only one source at a time. Speaker Push Terminals — press theappropriate tab to open a terminal. In-sert the end of a speaker wire into theopening, then rele...

Page 7 - CONNECTING SPEAKERS; One Speaker

7 • If you connect more than two speak- ers using only series or only parallelconnections, the total impedancemight exceed the amplifier’s maxi-mum impedance (16 ohms) or fallbelow its minimum impedance (4ohms). For example, if you connect four 8-ohm speakers: –In series, the total impedance is 32 o...

Page 11 - Controls and Operation

11 3. Connect a wire from the speaker’s positive (+) terminal to the trans-former’s secondary tap thatmatches the speaker’s total imped-ance (4, 8, or 16 ohms). 4. Connect a wire from the speaker’s negative (–) terminal to the COM tapon the transformer’s secondaryside. ˆ Controls and Operation MICRO...

Page 12 - Troubleshooting

12 ˆ Troubleshooting If you should run into difficulties, checkthe wiring of the system. Are there anyshort circuits in the speaker wiring?Have you provided adequate ventila-tion? Did you calculate speaker imped-ance correctly? Be sure microphones and connectingcables are not defective. Be sure you ...

Page 13 - Care and Maintenance; REPLACING FUSES; DC Cable; Amplifier

13 ˆ Care and Maintenance To enjoy your amplifier 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 from dust...

Page 14 - Specifications

14 ˆ Specifications Output Power at 1 kHz, 10% THD ............................................................................... 20 Watts THD at 1W, 1 kHz Low-Pass Filter MIC1 .............................................................................................................................

Page 15 - Notes

15 ˆ Notes 32-2001.fm Page 15 Friday, February 4, 2000 7:53 AM