CERWIN VEGA VCU84 (01) PDF Document

The CERWIN VEGA VCU84 amplifier includes the following features:

• Full Range Class D IR Chipset

• DirectFET Power Mosfet Output Stage

• SMD Technology on 4 layer Glass PC Board

• Conformal Coated PCB assembly for added water resistance

• ICAD circuit provides superior overload protection

• Frequency response 10 Hz – 30kHz

• Variable 12db crossovers

• Cerwin Vega Bass boost +12DB @45HZ

• Premium 8 gauge power connections

• Multi channels / Mono channel

Please observe the following general precautions during installation:

• This unit is designed for negative ground 12V DC operation only.

• The total system impedance for the VCU84 must not be less than 4 ohms bridged.

• Avoid installing the unit where it would be subject to high temperatures (from direct sunlight or hot air), rain, moisture, dust, or dirt.

• Do not cover the unit with carpet or wires.

• Do not use the unit with a weak auto battery. Optimum performance depends on an optimum battery supply voltage.

• For safety, keep your car audio system volume moderate while driving to hear normal traffic sounds.

• There is no speaker level input connector. You can cut RCA’s and solder the wires to connect directly through the low-level input (RCA) or purchase an “optional” RCA Adaptor cable (model – CHHILVL) for a cleaner installation.

Although the CERWIN VEGA VCU84 incorporates heat sinks and protection circuits, mounting it in a tight space without air movement can still damage internal circuitry. Observe the following precautions when mounting:

1. Choose a location that provides adequate ventilation around the amplifier. For easy system set-up, mount the amplifier so the side panel controls will be accessible after installation. To increase thermal run times on low impedance loads, an additional fan is recommended.

2. Use a felt pen to mark the mounting hole locations.

3. Mounting the amplifier on carpet will significantly reduce air flow, resulting in reduced thermal run times.

4. Mount the amplifier on a solid surface. Avoid mounting to subwoofer enclosures or areas prone to vibration. Do not install the amplifier on plastic or other combustible materials.

5. Before mounting, ensure you do not cut or drill into the fuel tank, fuel lines, brake lines (under chassis), or electrical wiring.

Follow these wiring precautions for a safe and effective installation:

1. Before starting, make sure the source unit power switch is in the OFF position.

2. Disconnect the negative (-) lead of the battery before making any power connections.

3. When making connections, be sure that each one is clean and secure. Insulate all connections to prevent damage to your equipment.

4. A secure, clean ground connection is critical. Connect the ground directly to the car chassis to minimize resistance and avoid noise problems.

5. Add an external fuse on the amplifier’s positive (+) power lead, connecting it as close as possible to the vehicle’s (+) battery terminal. Use a fuse with a rating that equals the total current consumption at full output of all amplifiers in the system. This protects the vehicle from short circuits that can cause a fire.

The Status LEDs indicate the amplifier’s operational state. They show when the amplifier is powered up normally and when there is a protection fault. The Protect LED will illuminate if there is a problem with your amplifier.

The Sensitivity control matches the preamp stage of the CERWIN VEGA VCU84 to your source unit; it is NOT a volume control. The range is approximately 200mV to 10V. To set the gain:

1. Turn the amplifier gains all the way down (counterclockwise).

2. Turn the source unit volume up to almost full (usually about 2/3rds of the way up) or until the output starts to distort on an oscilloscope. This is nearly full volume on some source units.

3. Increase the amplifier gain setting until adequate volume is achieved, or until distortion is audible. Then, turn the gain down a bit until the distortion is inaudible.

Note: Ideal signal-to-noise and dynamic range are achieved with the gain at a minimum. Most users find adequate gain and volume at less than halfway in the adjustment range. Avoid setting the gain very high, as this will significantly increase noise and distortion.

The CERWIN VEGA VCU84 can be switched on and off using one of three methods, selected by the “Turn-On Mode” switch. Note that DC and VOX settings ONLY work with speaker level input.

• REM: This is the standard and most preferred method. It uses a 12V trigger wire connected from the head unit’s remote output to the amplifier’s REM terminal. This provides instant on and off with the head unit.

• DC (DC Offset): When connected using high-level (speaker) inputs, this mode senses differences in ground in your wiring through the speaker leads and turns the amplifier on.

• VOX (Signal Sensing): This mode senses any audio signal input into the amplifier’s RCA connections, which then turns the amplifier on.

The VOX and DC methods provide turn-on capabilities when a 12V trigger wire is not available but may have some delay in turning the amplifier on and off.

The CERWIN VEGA VCU84 has a versatile crossover section for tuning your speakers:

• Crossover Selection Switch (X-OVER): This switch selects the crossover type.

– Use High Pass (HP) for midrange or high-frequency speakers, allowing only frequencies above the cutoff point to pass.

– Use Low Pass (LP) for subwoofers, allowing only frequencies below the cutoff point to pass.

– In the FLAT position, the crossover is bypassed, and all speakers will receive the full frequency range.

• Crossover Adjustment Knob (FREQ): After selecting HP or LP mode, use this knob to adjust the crossover frequency. The range of adjustment is from 40Hz to 400Hz. For system tuning, start with the frequency set at approximately 80Hz and fine-tune up or down based on your music choice and input level.

Use the 2/4 Channel Input Config switch on the CERWIN VEGA VCU84 in the following scenarios:

• 2CH Position: Use this setting when you are using only a stereo (2-channel) input but want all 4 output channels to have a signal. This distributes the 2-channel input signal to all 4 output channels.

• 4CH Position: Use this setting when you are providing separate front and rear inputs to the amplifier for 4-channel operation.

The switch is also used when bridging the amplifier to create a powerful 2-channel high-pass or stereo subwoofer amplifier (4 Ohms only, stereo OR bridged).

1. Plan Wire Routing: Keep RCA cables close together but isolated from the amplifier’s power cables and other high-power auto accessories to prevent noise. Use plastic or rubber grommets when feeding wires through the firewall or metal barriers.

2. Power Wire (+12V): Strip 5/8 inch of insulation from the end of the power wire. Insert the bare wire into the B+ terminal and tighten the set screw. The B+ cable MUST be fused 18 inches or less from the vehicle’s positive battery post.

3. Ground Wire (GND): Use a wire of the same gauge as the power connection. Strip 5/8 inch of insulation, insert it into the GND terminal, and tighten. Prepare the chassis ground by scraping paint from a metal surface and cleaning the area. Strip the other end, crimp a ring connector, and fasten it to the chassis with a non-anodized screw and star washer.

4. Remote Turn-On Wire (REM): Strip 5/8 inch of insulation, insert it into the REM terminal, and tighten. Connect the other end to a switched 12-volt positive source, typically the source unit’s remote amp turn-on lead.

5. Mount Amplifier: Securely mount the amplifier to a solid surface on the vehicle or amp rack. Avoid mounting on cardboard or plastic panels.

6. Connect Speakers: Speaker impedance should never be less than 2 Ohms stereo or 4 Ohms bridged. Use 18-gauge wire for most applications, or 16-gauge for leads over ten feet. Pay careful attention to polarity on the speakers and amplifier. Do NOT chassis ground any speaker leads.

The recommended fuse rating for the CERWIN VEGA VCU84 is 40A.

Yes, the CERWIN VEGA VCU84 can accept speaker level inputs. The easiest way to connect your radio’s speaker outputs is to buy stereo RCA cables, strip the wires on one end, and connect them to the OEM amplifier or head unit’s speaker outputs. Then, plug the RCA end directly into the amplifier’s RCA input harness. When using this method, you will need to set the Turn-On mode to either DC or VOX.

To bridge the 4-channel CERWIN VEGA VCU84 into a 2-channel amplifier, you can use “Y-Adaptors”.

1. Use a Y-Adaptor on the FRONT input (L/R) – this will now be your LEFT channel input.

2. Use another Y-Adaptor on the REAR input (L/R) – this will now be your RIGHT channel input.

3. Connect your speakers to the BRIDGED connections on the amplifier’s output harness. The FRONT bridged connection is now your LEFT output, and the REAR bridged connection is now your RIGHT output.

NOTE: You MUST connect ONLY a 4 ohm load when the amplifier is bridged!