85 x 4 4-Channel Trunk Mount Amplifier (120-1977) Preparation Faxback Doc. # 16921 CHOOSING A MOUNTING LOCATION The ideal location for mounting the amplifier is in your vehicle's trunk. Wherever you decide to mount it, choose a mounting location that: Does not interfere with the vehicle's operation. Lets you drill mounting holes without damaging other vehicle components. Allows enough space around the cooling fins for proper airflow and cooling. WARNING: The amplifier gets very hot while it is on. Do not touch the amplifier or place flammable objects near it while it is on. BEFORE YOU BEGIN THE INSTALLATION Before you install your amplifier, carefully read all the instructions in this owner's manual. You should be able to answer all of these questions about your vehicle's electrical and sound systems. Does my vehicle have a 12-volt negative ground system? (If it does not, you cannot use this amplifier.) Which of the amplifier's wires is the power wire? How do I connect a wire to the fuse box? Which amplifier terminals are line-level inputs, which are speaker- level inputs, and which are speaker outputs? IMPORTANT: Be aware that installation in your vehicle may require cutting or modifying your vehicle. Do not cut any of the amplifier's wires. If you cut any wire, you cannot obtain a refund or exchange on this product. Radio Shack will provide warranty service if you cut a wire and find the product is defective. CAUTIONS: To prevent damage to your amplifier or autosound system, you must first connect the ground, primary, and switched power wires (as described in "Connecting Ground and Primary/Switched Power") before you connect the speakers to the amplifier. Make the connections only in the order shown. Damage to the ampli- fier is possible if you connect any wire incorrectly. Turn on the power to test the connections before you perman- ently mount the amplifier (see "Testing the Power Connections"). Be sure your speakers can handle 85 watts per channel, if you connect the autosound system to two pairs of speakers (or 170 watts per channel if you connect the autosound system to only one pair of speakers). Each speaker must have an impedance of at least 4 ohms. Your local Radio Shack store carries a full line of speakers to choose from. CONNECTING GROUND AND PRIMARY/SWITCHED POWER 1. To prevent damage to your amplifier or autosound system while making the connections, disconnect the negative (-) cable from your vehicle's battery. NOTE: After you complete the connections and reconnect the battery wire, you will need to reset all clock/timer/memory devices in your vehicle. 2. Securely connect the supplied dark blue/white wire's spade connector end to the amplifier's REM (remote power) terminal. 3. Connect the dark blue/white wire's other end to your autosound system's switched power lead using a twist-on terminal connector (such as Cat. No. 64-3057, not supplied). NOTE: If your autosound system does not have a remote power output lead, connect this wire to a point in your vehicle's fuse box that provides 12-volt battery power when the ignition is set to ON or ACC. This connection turns on the amplifier when you turn your ignition switch to on (or to ACC) and turns off the amplifier when you turn off the ignition. 4. Connect the black wire's eyelet/spade terminal end to the amplifier's two GND terminals. 5. Securely connect the black wire's eyelet-terminal to a nearby metal ground, such as a bolt attached to a part of the vehicle's chassis. NOTE: Be sure the bolt is not insulated from the chassis by a plastic part or other insulating material. 6. Connect the red wire's eyelet/spade terminal end to the amplifier's two +12V terminals. 7. Remove the nut from the positive (+) cable's terminal bolt, mount the red wire's 50A fused eyelet terminal on the bolt, then replace and tighten the bolt. CAUTION: Due to the amplifier's high current requirement, you MUST connect the red wire's fused end directly to the vehicle's positive (+) battery cable terminal bolt or damage to your vehicle's wiring could result. NOTE: Do not reconnect your vehicle battery's negative (-) cable yet. CONNECTING TO YOUR AUTOSOUND SYSTEM Low Level Input Connections You can connect your autosound system's low-level phono output jacks to the amplifier's low-level phono input jacks. For the best results, use shielded audio cables, such as Cat. No. 42-2368 (not supplied). NOTE: For a cleaner, less noisy signal transfer between your autosound system and the amplifier, the amplifier's low input phono jacks are gold-plated. 1. Temporarily place the amplifier as close as possible to the selected mounting location. 2. If your autosound system has four phono outputs and you are using four speakers, connect the autosound system to the amplifier using audio cables as follows: front-left to CH1, front-right to CH2, rear-left to CH3, and rear-right to CH4. If you autosound system has four phono outputs but you are using only two speakers (front or rear), connect only the autosound system's corresponding output jacks to the amplifier using audio cables as follows: front-left to CH1 and front-right to CH2, or rear-left to CH3 and rear-right to CH4 If your autosound system has only two phono output jacks (left and right) and you are using four speakers, use two Y-adapter audio cables to make the connections as follows: NOTE: For the best results, use shielded phono plug-to-phono plug Y- adapter audio cables, such as Cat. No. 42-2368 (not supplied). Connect one of the Y-adapter's double phono plug ends to the amplifier's CH1 phono jack. Connect the other double phono plug end to the amplifier's CH3 phono jack. Connect the single phono plug end to the autosound system's left output jack. Connect one of the other Y-adapter's double phono plug ends to the amplifier's CH2 phono jack. Connect the other double phono plug end to the amplifier's CH4 phone jack. Connect the single phono plug end to the autosound system's right out- put jack. If your autosound system has only two phono output jacks (left and right) and you are using only two speakers, simply connect them to the amplifier's corresponding CH1 and CH2, or CH3 and CH4, phono jacks. High-Level Input Connections If your autosound system has only speaker outputs, you can connect them to the amplifier's HIGH INPUT CH4 CH3 and HIGH INPUT CH2 CH1 sockets using the floating ground connection or the common ground connection method. If your autosound system has four speaker outputs and you are going to use four speakers: If your autosound system has only two speaker outputs and you are going to use four speakers: CONNECTING THE SPEAKERS With the speakers placed in their approximate locations, run one speaker wire from each speaker to the amplifier. We recommend you use 16- or 18- gauge marked or color-coded wires to help you correctly connect the speakers to your amplifier. For the maximum bass response and the best overall performance, keep your speakers properly phased (connect + to + and - to -). CAUTION: Do not connect the speakers' negative (-) terminal wires to chassis ground. NOTE: Speaker wires have two conductors. Color-coded wires have a stripe running down one of the conductors or different colored insulation for each conductor. Your local Radio Shack store has a wide selection of speaker wire to choose from. Preparing the Speaker Wires 1. Separate each speaker wire's two conductors at both ends for a length of about 4 inches. 2. Strip the insulation from the ends of each conductor to expose 1/4 inch of wire. NOTE: Be sure to twist the ends to secure loose strands. Connecting Four Speakers 1. Connect one end of a speaker wire's marked conductor to the amplifier's CH1 + terminal (front-left positive). 2. Connect the unmarked conductor's end to the amplifier's CH1 - terminal (front-left negative). 3. Repeat Steps 1 and 2 to connect another speaker wire to the amplifier's CH2 (front-right) terminals. 4. Repeat Steps 1-3 to connect speaker wires to the amplifier's CH3 (rear-left) and CH4 (rear-right) terminals. 5. Connect the other ends of the four speaker wires so CH1 connects to the front-left speaker, CH2 to the front-right speaker, CH3 to the rear- left speaker, and CH4 to the rear-right speaker. Connecting Two Speakers (Unbridged Connection) If you are connecting only two speakers, you can connect them to the amplifier's front (CH1 and CH2) or rear (CH3 and CH4) speaker terminals. CAUTION: This is an unbridged connection that produces 85 watts per channel. If you do not have high power speakers, use this connection. 1. Connect one end of a speaker wire's marked conductor to the amplifier's +CH1 (front-left positive) or +CH3 (rear-left positive) terminal. 2. Connect the unmarked conductor's end to the amplifier's CH1- (front- left negative) or CH3- (rear-left negative) terminal. 3. Repeat Steps 1 and 2 to connect speaker wires to the amplifier's CH2+ and -CH2 (front-right) or CH4+ and -CH4 (rear-right) terminals. 4. Connect the other ends of the speaker wires so CH1 (or CH3) connects to the left speaker and CH2 (or CH4) connects to the right speaker. Connecting Two speakers (Bridged Connection) If you are connecting only two speakers (left and right), you can add (bridge) the power output of two channels (front and back) to produce the combined power of both from each of the two speakers. CAUTION: This is a bridged connection that produces 170 watts per speaker. Use this connection only if you have high quality speakers capable of handling a power output of 170 Watts. 1. Connect one end of a speaker wire's marked conductor to the amplifier's +CH (+ Bridged) terminal and the other end to the left speaker's positive (+) terminal. 2. Connect the unmarked conductor's end (in the same speaker wire) to the amplifier's CH2+ (Bridged -) terminal and the other end to the left speaker's negative (-) terminal. 3. Connect one end of a second speaker wire's marked conductor to the amplifier's +CH3 (+ Bridged) Terminal and the other end to the right speaker's negative (-) terminal. 4. Connect the unmarked conductor's end (in the same speaker wire) to the amplifier's CH4+ (Bridged -) terminal and the other end to the right speaker's positive (+) terminal. 5. Push in the right BRG/ST (Bridged/Stereo) switch to the BRG position to bridge the front speakers (CH1 and CH2). 6. Push in the left BRG/ST (Bridged/Stereo) switch to the BRG position to bridge the rear speakers (CH3 and CH4). Connecting Two Unbridged Speakers and One Unbridged Subwoofer 1. Connect two speakers to the CH1 and CH2 terminals (front speakers) or to the CH3 and CH4 terminals (rear speakers). 2. For an unbridged connection, connect the subwoofer to the amplifier's CH3 or Ch4 terminals (if you used the front speaker connections in Step 1) or CH1 or CH2 terminals (if you used the rear speaker connections in Step 1). 3. Push in X-OVER FREQ so you can later adjust the amplifier's sound to compensate for your vehicle's acoustics (see "Using the Frequency Crossover"). 4. Press and release the left and right BRG/ST (Bridged/stereo) switches to make sure they are off. Connecting Two Unbridged Speakers and One Bridged Subwoofer 1. Connect the two speakers to the CH1 and CH2 terminals (front speakers) or to the CH3 and CH4 terminals (rear speakers). 2. For a bridged connection, connect the subwoofer to the amplifier's +CH3 and CH4+ terminals (if you used the front speaker connections in Step 1) or the +CH1 and CH2+ terminals (if you used the rear speaker connections in Step 1). 3. Push in X-OVER FREQ so you can later adjust the amplifier's sound to compensate for your vehicle's acoustics (see "Using the Frequency Crossover"). 4. Press and release the right BRG/ST (Bridged/Stereo) switch to make sure it is off. 5. Push in the left BRG/ST (Bridged/Stereo) switch to the BRG position to bridge the rear speakers (CH3 and CH4). TESTING THE CONNECTIONS Before you permanently mount the amplifier, connect your vehicle battery's negative (-) cable, turn your vehicle's ignition to ON or ACC, then test the connections. The amplifier is properly connected to the autosound system and speakers if you can verify that the amplifier and the autosound system turn on properly and the speakers' sound is clear and unmuffled. If you cannot quickly verify that all components operate properly, immediately turn off your vehicle's ignition. Then disconnect your vehicle battery's negative (-) cable and recheck your connections. Once you verify that all components operate properly, mark the connections to insure easy identification of each wire, then follow the instructions under "Mounting the Amplifier." MOUNTING THE AMPLIFIER Before you begin mounting the amplifier, make sure you have the following supplied hardware necessary for mounting. 6 sheet-metal screws 6 spring washers 6 flat washers Then confirm that the amplifier fits your vehicle's mounting area. CAUTION: Be careful to not drill into anything behind the mounting surface 1. Temporarily disconnect your vehicle battery's negative (-) cable again. 2. To make mounting more convenient, temporarily disconnect the amplifier's connections (ground, primary power, remote power, your vehicle stereo's input, and speakers). 3. Using the mounting holes on the amplifier as a guide, mark the locations for the mounting holes. 4. Drill 9/64-inch holes in the marked locations, being careful not to damage anything behind the mounting surface. 5. Attach the amplifier to the mounting surface using the supplied sheet- metal screws and washers. 6. Reconnect the wiring. 7. Reconnect your vehicle battery's negative (-) cable.