Infinity 311A, 611A, 1211A, 7521A, 7541A Manual

reference series

311a,611a, 1211a,7521a, 7541a,5761a

instructions

Thank you for purchasing a Reference Series amplifier. In order that we may better serve you should you require warranty service for your new amplifier, please retain your original purchase receipt and read the enclosed warranty information card.

INTRODUCTION

WARNING!

Playing loud music in an automobile can hinder your ability to hear traffic and permanently damage your hearing. We recommend listening at low or moderate levels while driving your car. Infinity accepts no liability for hearing loss, bodily injury or property damage resulting from the use or misuse of this product.

IMPORTANT

To get the best performance from your Reference Series amplifiers, we strongly recommend

that installation be entrusted to a qualified professional. Although these instructions explain how to install Reference amplifiers in a general sense, they do not show specific installation methods that may be required for your particular vehicle. If you do not have the necessary tools or experience, do not attempt the installation yourself. Instead, please ask your authorized Infinity car audio dealer about professional installation.

INSTALLATION WARNINGS AND TIPS

•Always wear protective eyewear when using tools.

•Turn off the audio system and other electrical devices before you start. Disconnect the (–) negative lead from your vehicle’s battery.

•Check clearances on both sides of a planned mounting surface before drilling any holes or installing any screws. Remember that the screws can extend behind the surface.

•At the installation sites, locate and make a note of all fuel lines, hydraulic brake lines, vacuum lines and electrical wiring. Use extreme caution when cutting or drilling in and around these areas.

•Before drilling or cutting holes, use a utility knife to remove unwanted fabric or vinyl to keep material from snagging in the drill bit.

•When routing cables, keep input-signal cables away from power cables and speaker wires.

•When making connections, make certain they are secure and properly insulated.

•If the amplifier’s fuse must be replaced, use only the same type and rating as that of the original. Do not substitute another kind.

CHOOSING A LOCATION AND

MOUNTING THE AMPLIFIER

Choose a mounting location in the trunk or cargo area where the amplifier will not be damaged by shifting cargo. Amplifier cooling is essential for proper amplifier operation. If the amplifier is to be installed in an enclosed space, make sure there is sufficient air circulation for the amplifier to cool itself.

When mounting the amplifier under a seat, ensure that it is clear of all moving seat parts and does not affect the seat adjustments. Mount the amplifier so it is not damaged by the feet

of backseat passengers. Make sure that the amplifier is mounted securely using nuts and bolts or the supplied mounting screws.

Mount the amplifier so that it remains dry – never mount an amplifier outside the vehicle or in the engine compartment.

Figure 1.Terminal-connection end plate.

POWER CONNECTIONS

The Reference amplifiers are capable of delivering high power levels, and require a reliable connection to the vehicle’s electrical system in order to perform optimally. See Figure 1 for connection location. Please adhere to the following instructions carefully.

GROUND CONNECTION

Connect the amplifier’s Ground (GND) terminal to a solid point on the vehicle’s metal chassis, as close to the amplifier as possible. Refer to the chart below to determine minimum wire-gauge size. Sand away any paint from this location; use a star-type-lock washer to secure the connection.

POWER CONNECTION

Connect a wire (see chart at right for appropriate gauge) directly to the vehicle’s positive battery terminal, and install an appropriate fuse holder within 18" of the battery terminal. Do not

install the fuse at this time. Route the wire to the amplifier’s location, and connect it to the amplifier’s positive (+12V) terminal. Be sure to use appropriate grommets whenever routing wires through the firewall or other sheet metal. Failure to adequately protect the positive wire from potential damage may result in a vehicle fire. When you are done routing and connecting this wire to the battery and to the amplifier, you may install the fuse at the battery.The

fuse value should be selected based on total amplifier-current draw; see chart at right.

REMOTE CONNECTION

Connect the amplifier’s Remote (REMOTE) terminal to the source unit’s RemoteTurn-On lead using a minimum of 18-gauge wire. If your source unit does not have a remote turn-on connection, connect the amplifier’s (REMOTE) terminal to the vehicle’s accessory circuit.

WIRE-GAUGE CHART
Amplifier	Maximum	Minimum
Model	Current Draw	Wire Gauge
7521a	34A	#8 AWG
7541a	85A	#8 AWG
5761a	87A	#8 AWG
311a	40A	#8 AWG
611a	69A	#6 AWG
1211a	115A	#4 AWG

These recommendations assume 7' – 10' wire runs. If your installation differs markedly, you will need to adjust the wire gauge accordingly.

SPEAKER CONNECTIONS

Refer to the application guides on the pages that follow. Speaker connections should be made using a minimum of 16-gauge wire.

HIGH-LEVEL INPUT CONNECTIONS

The 7521a, 7541a and 5761a amplifiers are equipped with speaker-level inputs that allow you to add an amplifier to head units that do not have RCA line outputs.The speaker outputs for the source unit should be connected to the amplifier using the supplied connector (square four-wire plug). Remember to check for proper polarity.The 311a, 611a and 1211a amplifiers are not equipped with high-level inputs.

NOTE: When using the low-level or high-level inputs, the AUX outputs can be used to pass a full-range line-level signal to another amplifier.

Figure 2. Speaker-level connector.

HIGH-LEVEL

INPUT

+ +

R L

– –

GRAY + – WHITE/BLACK

GRAY/BLACK – + WHITE

L R

Speaker Wires (spliced)

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APPLICATIONS – 311a, 611a AND 1211a

The Reference subwoofer amplifiers are single-channel amplifiers.There are two sets of terminals to make it easy to connect multiple woofers. Either set of (+/–) terminals may be used when connecting woofers.

To the right are two application diagrams to help plan your subwoofer system installation. Figures 3 and 4 show how to configure the Reference subwoofer amplifiers (models 311a, 611a and 1211a).

NOTE: For simplicity, Figures 3 and 4 do not show power, remote and input connections.

NOTE: Minimum speaker load is 2 ohms.

APPLICATIONS – 7521a

Figure 3. Reference subwoofer amplifier with two woofer connections.						Figure 4. Reference subwoofer amplifier with one woofer connection.

The 7521a amplifier can be set up for stereo or bridged-mono operation, as shown in Figures 5 and 6.

NOTE: For simplicity, Figures 5 and 6 do not show power, remote and input connections.

NOTE: Minimum speaker impedance for stereo operation is 2 ohms. Minimum speaker impedance for bridged operation is 4 ohms.

Figure 5. 7521a amplifier set up for stereo operation.

Figure 6. 7521a amplifier set up for bridged-mono operation.

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