www.radioshack.comSM OWNER’S MANUAL — Please read before using this equipment. 32-2054 Thank you for purchasing the RadioShack 40W AC/DC PA Amplifier. It gives you the versatility and power you need in a professional sound system. Your amplifier’s wide frequency response easily handles amplification of voice and music. Use it in meeting halls and auditoriums, at sports events, in schools, and in the office for paging systems - anywhere you need to deliver special announcements with excellent sound.
Front View of Amplifier Phono/Aux Rotary Volume Control - lets you adjust the volume of the turntable or auxiliary sound source (See Page 15). Output Power Level LED Indicator - lets you monitor and control the output power level (See Page 15). On/Off Rocker Switch with LED Indicator - lights to indicate power is turned on (See Page 15). Microphone Rotary Volume Controls - lets you adjust the microphone level (see Page 15).
Rear View of Amplifier COM/4Ω/8Ω/16Ω/70V Speaker Connectors - let you easily connect speaker wires directly to the amplifier after the total speaker impedance is determined (See Page 9). AC IN - supports other music instrument/amplifier power with maximum load of 100W (See Page 14). DC 5A/12V Input Jack - lets you power the amplifier from a 12V vehicle battery source (See Page 15). Ground Screw - connect the ground wire (black or green) to this screw to avoid low-frequency hum.
%106'065 Preparation Preparation ............................ 4 Placing the Amplifier .......... 4 Placing the Speakers ......... 4 Presetting the Controls ...... 4 Connections .......................... 5 Connecting Input Sources... 5 Connecting the Speakers..... 7 One Speaker ................... 9 Two Speakers in Series .. 9 Two Speakers in Parallel .......................... 10 Series/Parallel Comb. ... 11 Speakers w/Transform. . 12 Connecting Power ............... 15 Connecting the DC Jack ....
2TGUGVVKPI VJG #WFKQ +PRWV 5QWTEGU Set the audio input sources’ controls to these levels. Audio Device Control Turntable Power Setting Off Tape Deck Power Off CD Player Power Off Amplifier Receiver Power Tone Off Flat 2TGUGVVKPI VJG #ORNKHKGT Control Setting Power Out MIC 1, MIC 2, PHONO/AUX MIN 100 Hz, 1 kHz, 8 kHz 0dB (mid position) MASTER VOLUME MIN Connections Warning: To prevent possible hearing loss, set the amplifier’s controls to the settings shown below.
%QPPGEVKPI /KETQRJQPGU You can connect one dynamic microphone (not supplied) to MIC 1 and another to MIC 2 using a 1/4” (6.35 mm) plug. MIC 1 MIC 2 Connections %QPPGEVKPI C 6WTPVCDNG You can connect a low level audio input source, such as a magnetic cartridge turntable, to the amplifier’s L and R PHONO jacks. With this connection, set the PHONO and AUX/CD selector switch to PHONO.
%QPPGEVKPI VJG /+: $75 ,CEM You can connect another MP-40 amplifier to this jack (shown on page 3) to double the size of your PA system. This lets you use up to four microphones and two turntables (or two auxiliaries) sound sources. Use a shielded cable with phono plugs at each end to connect the amplifier. Connect the cable between the two amplifiers’ MIX BUS jacks. For the best results, use the most appropriate cable length.
± 016' ± For the best results when connecting speakers (in series or parallel), only use speakers having the same impedance. Important: If you are connecting more than two speakers in series only or parallel only, be sure the total impedance does not exceed the amplifier’s maximum impedance (16 ohms) or fall below the minimum impedance (4 ohms). You can achieve a proper total impedance by combining series and parallel connections ±.
%100'%6+0) 10' 52'#-'4 Connections Connect the speaker’s negative (-) terminal to the amplifier’s COM terminal. Then, connect the speaker’s positive (+) terminal to the speaker terminal (4 Ω, 8 Ω, or 16 Ω) that matches the speaker’s impedance. Speaker Terminals %100'%6+0) 691 52'#-'45 +0 5'4+'5 Speakers are connected in series when the first speaker’s positive terminal is connected to the next speaker’s negative terminal.
Connections Follow these steps to connect speakers in series. 1. Connect the first speaker’s positive terminal to the other speaker’s negative terminal. 2. Connect the first speaker’s negative terminal to the amplifier’s COM terminal. 3. Connect the other speaker’s positive terminal to the amplifier’s terminal (4 Ω, 8 Ω, or 16 Ω) that matches the total speaker impedance. %100'%6+0) 691 52'#-'45 +0 2#4#..'.
Connections Follow these steps to connect two speakers in parallel. 1. Connect both speaker’s negative (-) terminals to each other. Then, connect both wires to the amplifier’s COM terminal. 2. Connect both speakers’ positive (+) terminals to each other. Then, connect both wires to the amplifier’s speaker terminal (4 Ω, 8 Ω, or 16 Ω) that matches the total speaker impedance. %100'%6+0) (174 52'#-'45 +0 5'4+'5 2#4#..'. %1/$+0#6+10 Follow these steps to combine series and parallel combinations±. 1.
3. Connect each pair of speakers in parallel. If you connected 8-ohm speakers, the total impedance of both pairs is 8 ohms (16/2 = 8). 4. Connect the speakers’ negative (-) terminals to the amplifier’s COM terminal. 5. Connect the speakers’ positive (+) terminals to the amplifier’s (4 Ω, 8 Ω, or 16 Ω) terminal that matches the total speaker impedance, as calculated in Step 3.
Transformers allow you to: • connect speakers with different impedances without causing output differences between the speakers. • add or remove a speaker from the system without having to recalculate the entire system’s impedance. • reduce signal loss when you use speaker wire over 50 feet (15.24 meters) long. Follow these steps to connect the speakers with the transformers. Example shown on next page. 1. Connect a wire from the amplifier’s 70V terminal to the transformer’s desired primary tap (10, 5, 2.
Amplifier Connections Note: The wires labeled with an A are connected to each other. %100'%6+0) 219'4 To connect the amplifier to power, plug the female end of the supplied AC power cord into the amplifier’s AC IN jack and the other end to any standard AC outlet.
To power the amplifier from your vehicle’s 12V battery, plug the supplied DC power cable’s barrel plug to the DC 12V IN jack, and then connect the other end to your vehicle’s 12V accessory socket, such as a cigarette-lighter socket. 4'2.#%+0) 6*' &% 219'4 %14& 5 (75' If the amplifier does not operate from a 12V battery source, check the fuse in the cigarette lighter plug. If the fuse is blown, remove the cap of the plug and replace the fuse with the proper type and rating (6A/250V).
• Put the headphones on, and then gradually increase the volume to your desired listening level. Troubleshooting • Do not listen at extremely high volume levels. Extended high-volume listening can lead to permanent hearing loss. • Once you set the volume, do not increase it. Over time, your ears adapt to the volume level, so a volume level that does not cause discomfort might still damage your hearing. 6417$.'5*116+0) We do not expect you to have any problems with your amplifier.
• 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 damp cloth occasionally to keep it looking new. Care %#4' 5'48+%' #0& 4'2#+4 If your amplifier is not performing as it should, take it to your local RadioShack store for assistance.
52'%+(+%#6+105 Output Power at THD 10%, 4-Ohm Load 1 kHz ....... 40W Specifications Total Harmonic Distortion (at 5 Watts, 4 ohms, 1 kHz, with Band Pass Filter) MIC................................................................... 0.50% AUX.................................................................. 0.10% PHONO ............................................................ 0.30% Input Sensitivity (at 10%, THD, 1kHz) MIC..................................................................2.5 mV AUX.......
#%%'5514+'5 The following accessories are available at your local RadioShack store. To locate your nearest RadioShack, use the store locator feature on RadioShack’s website (www.radioshack.com), or call 1-800-The Shack (843-7422) and follow the menu options.
Limited One-Year Warranty This product is warranted by RadioShack against manufacturing defects in material and workmanship under normal use for one (1) year from the date of purchase from RadioShack companyowned stores and authorized RadioShack franchisees and dealers.
