User`s guide

ManualsBrandsRadio Shack ManualsAmplifier32-2055

Please read this user’s guide before installing,

setting up and using your new product

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250W Power Amplifer Quick Start Guide

User’s Guide

Thank you for purchasing your 250-Watt Power Ampliﬁ er

from RadioShack. This PA gives you the versatility and power

you need in a professional sound system. Its wide frequency

response easily handles ampliﬁ cation of voice and music.

Use it anywhere you need to deliver special announcements

with excellent sound. It is perfect for meeting halls,

auditoriums, sporting events, schools, or in the ofﬁ ce for

paging systems. With a bridged speaker connection, the

ampliﬁ er can produce up to 350 watts of clean, powerful

sound with minimum distortion.

32-2055

250-watt stereo

power ampliﬁ er

Summary of content (15 pages)

PAGE 1
32-2055 250-watt stereo power ampliﬁer Thank you for purchasing your 250-Watt Power Ampliﬁer from RadioShack. This PA gives you the versatility and power you need in a professional sound system. Its wide frequency response easily handles ampliﬁcation of voice and music. Use it anywhere you need to deliver special announcements with excellent sound. It is perfect for meeting halls, auditoriums, sporting events, schools, or in the ofﬁce for paging systems.
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The Basics The Basics contents features 4 front view ................................................................. 4 rear view .................................................................. 6 important safety instructions (UL 6500) setting up your new ampliﬁer using speaker A/B replacing the fuse product speciﬁcations FAQs 24 24 26 27 8 12 ﬁnd a home for your new ampliﬁer ........................ 12 preset the controls ..................................................
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The Basics The Basics features CLIPPING Indicator Lights up to remind you to reduce volume when the ampliﬁer output is too high. front view Illuminated Power Switch Lights up when you turn on the switch. Output Power Level LED Indicators Indicate the total stereo output power level MIC 1, MIC 2, and MIC 3 Adjust volume for the connected microphones. A/B Speaker Switch Select the speakers you want to use with the ampliﬁer in Channel A, Channel B, or both (for use with 8 ohm speakers only).
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The Basics The Basics rear view Cooling Fan Automatically activated whenever the ampliﬁer is turned on. This forced air cooling system rapidly exhausts interior heat to reduce operating temperature. XLR Balanced Microphone Inputs Connect up to four highimpedance microphones to your ampliﬁer. Audio Input Jacks Connect input sources (CD or DVD player, TV, etc.) here, via an unbalanced audio cable. Match the colors on your cable connections with the colors on the jacks.
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The Basics The Basics important safety instructions (UL 6500) 1. Read all safety and operating instructions before the appliance is operated. 2. Keep all safety and operating instructions for future reference. 3. Follow all warnings on the appliance and in the operating instructions. 4. Unplug this appliance from the wall outlet before cleaning. Use only a damp cloth for cleaning. Do not use liquid or aerosol cleaners. 5.
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The Basics The Basics 17. Move appliance and cart combinations with care. Quick stops, excessive force, and uneven surfaces may cause the appliance and cart combination to overturn. 18. Unplug this appliance from the wall outlet and refer servicing to qualiﬁed service personnel under the following conditions: • When the power-supply cord or plug is damaged. • If liquid has been spilled or objects have fallen into the appliance. • If the appliance has been exposed to rain or water.
PAGE 7
The Basics The Basics setting up your new ampliﬁer presetting the ampliﬁer To prevent possible hearing loss, set the controls on the ampliﬁer to the following: Control Setting ﬁnd a home for your new ampliﬁer POWER Out Before you use your ampliﬁer, be sure to place it on a surface with adequate ventilation. Do not put it on thick carpeting, which can restrict air ﬂow, or near a heat source such as a heat vent or radiator, which can cause it to overheat.
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The Basics The Basics connecting an auxiliary sound source Balanced Microphone Jacks NOTES Unbalanced Microphone Jacks • If your microphone cord is longer than 20 feet (6 meters), we recommend that you connect it to a balanced jack to reduce signal hum. 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.
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The Basics The Basics connecting speakers You can connect one or more 4-, 8-, or 16-Ohm speakers to the ampliﬁer. To ensure equal volume from each speaker, all connected speakers should have the same impedance rating. Proper phasing 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 volume, and can have a signiﬁcantly decreased bass effect .
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The Basics The Basics unbridged connection Use this connection if you are connecting more than one speaker on the same channel or if you do not have highpower speakers. connecting two speakers in parallel Speakers are connected in parallel when the speakers’ negative terminals are connected together and all their positive terminals are connected together.
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The Basics The Basics bridged connection connecting power Use this connection if you have high power speakers that can handle a power output of 350 Watts. To connect the ampliﬁer to power, plug the attached power cord into a standard AC outlet. Your ampliﬁer's fuse (located on the ampliﬁer's back panel) protects the ampliﬁer from voltage surges. If the ampliﬁer does not work when you press POWER, check the fuse. If it is blown, see "Replacing the Fuse.
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The Basics Beyond the Basics operating your ampliﬁer 1. Start the input sound source. 2. Make sure LEFT and RIGHT volume control on the front of the ampliﬁer are set to MIN. Left Volume Control monitoring sound sources To monitor the sound sources, plug a pair of mono or stereo headphones (not supplied) with a ¼-inch (6.35mm) plug into the PHONES jack on the front of the ampliﬁer. Headphones sometimes make it easier to check and adjust the sound source's balance. Right Volume Control 3.
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Beyond the Basics Beyond the Basics using the level meters and clipping indicator The illuminating ﬂow of the output LED indicators reﬂect the ampliﬁer’s output level. The stronger the signal the more LEDs illuminate. The maximum signal through the MPA-250 should cause the CLIPPING LED to blink at peak music levels. LED Indicators CLIPPING LED using speaker A/B NOTE • Let the ampliﬁer cool down and see if it starts again before you presume a fuse needs to be replaced.
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Beyond the Basics Beyond the Basics product speciﬁcations FAQs Input Impedance................................................................. 20k Ohms Continuous Output Power Stereo at 1 kHz ....................................... 125 Watts x 2 (8 Ohms) Stereo at 1 kHz ....................................... 175 Watts x 2 (4 Ohms) Bridged at 20 Hz to 20 kHz .......................... 250 Watts (8 Ohms) Bridged at 1 kHz ...........................................
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• Keep the ampliﬁer dry. If it gets wet, wipe it dry immediately. • Use and store the ampliﬁer only in room temperature environments. • Handle the ampliﬁer carefully; do not drop it. • Keep the ampliﬁer away from dust and dirt, and wipe it with a soft cloth occasionally to keep it looking new. • If your ampliﬁer is not performing as it should, take it to your RadioShack store for assistance. To locate your nearest RadioShack, use the store locator feature on RadioShack's website (www.radioshack.