Crown CMA-1 Installation Instructions

Introduction

This document provides installation instructions for the Crown CMA-1 mobile amplifier. Please read the enclosed warranty statement before proceeding with installation. The installation of the CMA-1 is complex and should only be attempted by individuals with the proper tools and knowledge. This amplifier is designed for state-of-the-art mobile fidelity and requires corresponding installation methods to achieve its full benefits.

Important Cautions

CAUTION: The CMA-1 can draw extremely large current from the vehicle's battery. A standard automobile charging system may be insufficient, potentially leading to battery discharge even when the engine is running. It is recommended that the owner/operator consider installing a higher-amperage alternator and a secondary battery. The amplifier's power consumption is a maximum of 73 amps DC, with a nominal draw of 10-40 amps DC at 12-14 VDC.

Use a minimum of #8 gauge stranded cable (with #6 gauge recommended) for both positive (+) and negative (-) leads connecting the battery to the CMA-1. Do not splice these cables. Connecting these cables anywhere other than directly to the battery terminals is not acceptable, as it could cause the vehicle's wire harness to melt due to the CMA-1's current draw. Using cable thinner than #8 gauge may cause overheating, a fire hazard, reduce available 12VDC power, and degrade performance. Using cable smaller than #8 gauge could void the warranty. For lengths over 12 feet or for installations requiring the highest possible performance, #6 gauge stranded cable is highly recommended. Ensure the cable used is specifically intended for automotive applications.

It is crucial to install a 60-amp fuse in the +12VDC power wire at the battery. This fuse is essential for preventing fires caused by wiring shorts to the vehicle chassis due to improper installation or unforeseen accidents. Fusing the speaker lines is also highly recommended to protect the speakers; refer to Figure 1 (Fuse-Size Nomograph) to determine appropriate speaker-fuse values.

If speaker cables need to be spliced to adjust length, ensure the splices are mechanically and electrically sound. Simply twisting wires together and wrapping with electrical tape is insufficient. Insulated crimped terminals, wire nuts wrapped with electrical tape, or solder connections with wire nuts wrapped with electrical tape are strongly recommended. Avoid pinching or piercing speaker cables during installation. Route speaker cables separately from amplifier input cables to prevent oscillations. Always observe the correct polarity of plus (+) and minus (-) wires when making connections.

Due to its extreme output power, the CMA-1 can damage certain loudspeaker models if abused. Ensure that the speakers used can handle the amplifier's output power. After installation, gradually increase the volume and avoid overdriving the speakers.

Accessories Supplied

• 60-amp fuse
• Fuse Holder
• Input cable harness
• Remote on/off cable

Mounting Instructions

Mount the CMA-1 securely to the vehicle chassis or a wooden panel. Ensure adequate airspace (at least 1 inch) and sufficient airflow around the heat fins for proper cooling. The CMA-1 can be mounted horizontally or vertically in the trunk or behind rear car seats. DO NOT place the CMA-1 in the engine compartment or in an area exposed to a harsh environment. Avoid mounting near the vehicle heater.

The dimensions of the CMA-1 are 16 inches (Length) x 14-1/2 inches (Width) x 3-5/8 inches (Height). Mounting-hole locations are illustrated in Figure 2 (CMA-1 Mounting-Hole Locations), which can also be used as a template.

Wiring and Connections

Power Wiring

Refer to Figure 3 (Power-Wiring Connections) for a visual guide. Before beginning installation, disconnect the Positive (+) battery power cable and do not reconnect it until the installation is complete.

1. Using a minimum size #8 stranded cable (#6 recommended) with a terminal, connect the CMA-1 terminal marked "-" to the negative (-) terminal of the battery. Do not splice this cable. Connecting this cable anywhere other than the battery is not acceptable, as it could cause the vehicle's wire harness to melt.
2. Using a minimum size #8 stranded cable (#6 recommended) with a terminal, connect the CMA-1 terminal marked "+" to the positive (+) battery cable terminal that was removed. Do not splice this cable, except for the fuse holder. Connecting this cable anywhere other than the battery is not acceptable. If using the same cable for both positive and negative connections, clearly mark the positive cable to prevent miswiring, as improper connection can damage the amplifier, battery, or electrical system.
3. Install the supplied 60-amp fuse in the Positive (+) cable near the battery. Failure to install this fuse could result in a vehicle fire due to accidental shorting of the power cables.

Remote On/Off Wiring

Refer to Figure 4 (Remote On/Off Wire Connection) for guidance.

1. Turn down your sound system volume to the minimum setting.
2. The green "remote" wire on the CMA-1 acts as the amplifier's on/off switch. Connect this green remote wire to a switched +12 VDC supply. This can be achieved through the ignition key, the tape deck/tuner, or a switched terminal at the fuse box. Some tuners are equipped with a dedicated switched +12V terminal for this purpose.
3. Important Note: Do not confuse the green remote wire with the green speaker wire (as shown in Figure 4). DO NOT connect the green wire to the main +12VDC power supply lead or any other continuously "hot" sources, as this will keep the amplifier constantly on and drain the battery.
4. Do not turn on the power until the speaker cables have been installed.

Multi-Channel Options

The CMA-1 features switch-selectable multi-channel formats, offering the following configurations:

• 3 Channel: 3x100 W
• 4 Channel: 2x100 W plus 2x50 W
• 5 Channel: 1x100 W plus 4x50 W

This flexibility allows for configurations such as 2-channel plus subwoofer, as well as other custom installation variations.

NOTE: The CMA-1 inputs are high-impedance line-level inputs. Speaker outputs from the car radio should NOT be wired into this amplifier. When connecting tuner/tape deck outputs to the CMA-1 inputs, use an appropriate connector or solder the connections and insulate them with electrical tape. All connections must be mechanically and electrically secure to prevent issues.

5-Channel Wiring

Refer to Figure 5 (5-Channel Connections) and Figure 6 (Switch Position for 5 CH Operation).

1. The amplifier inputs are provided via white cables, each marked with a numbered band at its end. Connect CH 1 signal (left-front) to white input cable 1, CH2 signal (right-front) to white input cable 2, CH3 signal (left-rear) to white input cable 3, CH4 signal (right-rear) to white input cable 4, and CH5 signal (Subwoofer) to white input cable 5.
2. Set the amplifier switch to the 5 CH position as shown in Figure 6. This configuration provides the following output powers: CH1: 50 W at 4 ohms, CH2: 50 W at 4 ohms, CH3: 50 W at 4 ohms, CH4: 50 W at 4 ohms, CH5: 100 W at 8 ohms. (These are minimum recommended loads.)
3. Refer to Figure 5 for speaker connections. Route the CMA-1 colored output cables separately from its white input cables to prevent oscillations. Using crimp terminals, connect the CMA-1 colored cables to the speaker terminals, carefully observing the cable colors and polarities:
   • Black/White (CH 1+) and Black (CH 1-) connect to the Left-Front Speaker.
   • White/Red (CH 2+) and White (CH 2-) connect to the Right-Front Speaker.
   • Red/White (CH 3+) and Red (CH 3-) connect to the Left-Rear Speaker.
   • Green/Yellow (CH 4+) and Green (CH 4-) connect to the Right-Rear Speaker.
   • Blue/Red (CH 5+) and Yellow/Red (CH 5-) connect to the Subwoofer.

4-Channel Wiring

Refer to Figure 7 (4-Channel Connections) and Figure 8 (Switch Position for 4 CH Operation).

1. Connect CH 1 signal (left-front) to white input cable 1, CH2 signal (right-front) to white input cable 2, CH3 signal (left-rear) to white input cable 3, and CH4 signal (right-rear) to white input cable 5.
2. NOTE: White input cable 4 is not used. To prevent accidental shorting of this cable to the chassis and to reduce noise, use a wire nut to connect both the "hot lead" and shield of white cable 4.
3. Set the amplifier switch to the 4 CH position as shown in Figure 8. This configuration provides the following output powers: CH1: 50 W at 4 ohms, CH2: 50 W at 4 ohms, CH3: 100 W at 8 ohms, CH4: 100 W at 8 ohms. (These are minimum recommended loads.)
4. Refer to Figure 7 for speaker connections. Route the CMA-1 colored output cables separately from its white input cables to prevent oscillations. Using crimp terminals, connect the CMA-1 colored cables to the speaker terminals, observing the cable colors and polarities:
   • Black/White (CH 1+) and Black (CH 1-) connect to the Left-Front Speaker.
   • White/Red (CH 2+) and White (CH 2-) connect to the Right-Front Speaker.
   • Red/White (CH 3+) and Green/Yellow (CH 3+) connect to the Left-Rear Speaker or Left Subwoofer.
   • Blue/Red (CH 4+) and Yellow/Red (CH 4-) connect to the Right-Rear Speaker or Right Subwoofer.
5. NOTE: The Red and Green cables (associated with CH4 in this diagram) are not used. To avoid accidental shorting, clip exposed ends back to the insulation and cover with electrical tape.

3-Channel Wiring

Refer to Figure 9 (3-Channel Connections) and Figure 10 (Switch Position for 3 CH Operation).

1. Connect CH 1 signal (left) to white input cable 1, CH2 signal (right) to white input cable 2, and CH3 signal (Subwoofer) to white input cable 5.
2. NOTE: White input cables 2 and 4 are not used. To prevent accidental shorting of these cables to the chassis and to reduce noise, use a wire nut to connect both the "hot lead" and shield in each unused cable.
3. Set the amplifier switch to the 3 CH position as shown in Figure 10. This configuration provides the following output powers: CH1: 100 W at 8 ohms, CH2: 100 W at 8 ohms, CH3: 100 W at 8 ohms. (These are minimum recommended loads.)
4. Refer to Figure 9 for speaker connections. Route the CMA-1 colored output cables separately from its white input cables to prevent oscillations. Using crimp terminals, connect the CMA-1 colored cables to the speaker terminals, observing the cable colors and polarities:
   • Black/White (CH 1+) connects to the Left Speaker.
   • White/Red (CH 2+) and Red/White (CH 2+) and Green/Yellow (CH 2+) connect to the Right Speaker.
   • Blue/Red (CH 3+) and Yellow/Red (CH 3-) connect to the Subwoofer.
5. NOTE: The Back, White, Red, and Green cables (not used in this configuration) should have their exposed ends clipped back to the insulation and covered with electrical tape to prevent accidental shorting.

Operation

1. After all connections are made, double-check them to ensure they are mechanically and electrically sound. Verify the correct polarity of all cables.
2. Check that there are no shorts to the vehicle chassis.
3. Ensure that the CMA-1 input and output cables are routed separately from each other.
4. Connect the positive battery-cable terminal to the battery. This terminal should already have the CMA-1 positive cable attached to it.
5. With your sound system volume turned all the way down, apply power to the CMA-1 by turning on your ignition key or tape deck/tuner.
6. After the 5-second turn-on delay, slowly turn up the volume and enjoy your music. Avoid overdriving the speakers.

Troubleshooting

No Sound from All Speakers or Some Speakers

1. Recheck cable connections and routing according to this instruction sheet.
2. Check the fuse in-line with the +12VDC power cable. If the fuse is blown, find and repair the cable short to the vehicle frame, then replace the fuse with one of the same value.

Distorted (Gritty) Sound

1. Turn down the volume of your sound system.
2. Turn down the bass of your sound system.
3. Turn down the low-frequency control(s) on your graphic equalizer.
4. Recheck cable connections at the speaker terminals for shorts. Ensure that the CMA-1 colored output cables are routed separately from its white input cables.

Static (Radio Interference, Ignition, Noise)

1. Recheck all connections.
2. Use radio-suppressor spark-plug cables.
3. Use resistor-type spark plugs.
4. Ensure that all external equipment, such as radios, tape decks, equalizers, and electronic crossovers, have one main ground point.
5. Try to pinpoint the source of the static, such as the radio, equalizer, crossover, or power amplifier. Make sure these units are not defective.
6. Check for proper antenna grounding.
7. If the ignition system uses a distributor with points, check the capacitor on the distributor and also the capacitor on the coil.
8. Try re-routing the input and output cables.
9. Check for a bad alternator.
10. Make sure all power-cable connections are tight and secure.
11. Re-route the power cables.

Service Policies

Due to the sophisticated circuitry of the CMA-1, only qualified, fully trained technicians should be allowed to service it.

Specifications

Output Power (20Hz-20kHz)

Performance Metrics

Electrical

• Input Sensitivity: .775V
• Input Impedance: >10K ohm
• Supply Voltage: 12-14 VDC
• Power Consumption: 73 amps DC max., 10-40 amps DC nominal

Physical

• Size: 16"L x 14-1/2"W x 3-5/8"H
• Weight: 20 lbs.