JBL Marine A754 and Marine A5055 Amplifiers
This document provides instructions and specifications for the JBL Marine A754 and Marine A5055 amplifiers, designed for marine audio systems.
What's in the Box
- Marine A754 Amplifier
- Marine A5055 Amplifier
- Owner's Manual
Accessing Connectors and Control Panel
To access the amplifier's connectors and control panel:
- Pry off the trim piece.
- Slide the panel cover down.
- Remove the panel cover.
The control panel features various controls for input level, turn-on mode, gain, crossovers (HPF, LPF, FULL), frequency, bass boost, and phase. It also includes indicator lights for Power (PWR) and Protection (PROT), and connection terminals for +12V, REM (Remote Turn-On), and GND (Ground).
Mounting the Amplifier
It is recommended to make all wire connections before permanently mounting the amplifier.
Important Installation Notes:
- Disconnect the negative [negative-terminal-symbol] battery terminal of the accessory battery before beginning installation.
- Always wear protective eyewear when using tools.
- Choose a safe mounting location. Ensure adequate clearance and that screws or wires will not puncture the vessel hull, fuel lines, or wiring harnesses. Ensure wire routing does not interfere with safe boat operation. Exercise caution when drilling or cutting.
- Select a location that provides sufficient air circulation.
- Do not mount the amplifier with the heat sink facing downward, as this interferes with cooling.
- Mount the amplifier so it will not be damaged by passenger feet or shifting cargo.
Wiring
Power and Ground Wiring
At the amplifier: Connect the +12V terminal to the battery via a fuse holder (30A fuse recommended, 18" (46cm) wire length). Connect the REM terminal to the remote turn-on output of your stereo (used only with low-level signal inputs). Connect the GND terminal to a solid chassis ground point using a ring connector and star washer. Ensure the ground wire is of appropriate gauge.
At the ground location: Use a factory bolt or a dedicated ground point. Remove any paint below the ring connector for a secure connection.
Input Signal Wiring
Marine A754 Low-Level Signals: Connect RCA cables from the stereo's front and rear low-level outputs to the amplifier's FRONT and REAR inputs, respectively. Connect to optional second amplifier low-level inputs if needed. When using low-level signals and remote turn-on, set the appropriate switches (refer to specific model diagrams for exact switch labels).
Marine A5055 Low-Level Signals: Connect RCA cables from the stereo's front, rear, and subwoofer low-level outputs to the amplifier's FRONT, REAR, and SUB inputs, respectively. Connect to optional second amplifier low-level inputs if needed. When using low-level signals and remote turn-on with the A5055, set the "REM" switch to "EXT", the SUB "LPF" switch to "320Hz", and the "PHASE" switch to "0°" (example settings, refer to specific model diagrams).
Marine A754 High-Level Signals: Loosen screws on the amplifier's input terminals, insert speaker wires from the stereo's front and rear speaker outputs, and tighten screws. Remove any paint below the ring connector. When using high-level signals, set the "HPF" switch to "FULL" and the "LPF" switch to "FULL" (example settings). If no sound plays, change the "HPF" switch to "32Hz" (example troubleshooting step).
Marine A5055 High-Level Input Signals: Connect speaker wires from the stereo's front and rear speaker outputs to the amplifier's FRONT and REAR inputs. When using high-level signals with the A5055, set the "HPF" switch to "FULL", the SUB "LPF" switch to "320Hz", and the "PHASE" switch to "0°" (example settings). If no sound plays, change the "HPF" switch to "32Hz" (example troubleshooting step).
Output Wiring
Marine A754 4-Channel Output (4 ohm/2 ohm): Connect the front left speaker to the FRONT L (+/-) terminals, front right speaker to FRONT R (+/-), rear left speaker to REAR L (+/-), and rear right speaker to REAR R (+/-).
Marine A754 3-Channel Output (Front: 4 ohm/2 ohm; Rear: 4 ohm): Use FRONT L/R for stereo front speakers and REAR L/R bridged for a subwoofer.
Marine A754 2-Channel Output (4 ohm): Use FRONT L/R bridged for a subwoofer.
Marine A5055 5-Channel Output (4 ohm/2 ohm): Connect front left speaker to FRONT L (+/-), front right speaker to FRONT R (+/-), rear left speaker to REAR L (+/-), rear right speaker to REAR R (+/-), and subwoofer to SUB (+/-).
Connecting the Remote Bass Controller (Marine A5055 Only)
Connect the remote bass controller to the dedicated port on the amplifier for adjusting subwoofer volume remotely.
Setting Gain, Crossovers, and Bass Boost
Setting the Gain
- Start with the GAIN control set to minimum and the crossover control rotated midway.
- For front and rear channels, choose music you are familiar with. For the subwoofer channel on the Marine A5055, choose music with substantial bass content.
- Turn the volume control on your receiver to about 3/4 of its total output.
- Adjust the GAIN control clockwise, listening carefully to the bass output. If you hear distortion, turn the GAIN control counterclockwise to decrease the gain.
Selecting the Crossover Mode
On the front and rear channels, you can select your preferred crossover mode:
- HPF (High-Pass Filter): Allows only frequencies above a certain point to reach your speakers. Recommended if using a subwoofer, as it prevents low bass from reaching full-range speakers.
- LPF (Low-Pass Filter): Allows only frequencies below a certain point to reach your speakers. Recommended if bridging front or rear channels to power a subwoofer.
- FULL: Allows all frequencies to reach your speakers. Recommended if not using a subwoofer.
Note: The crossover mode for the subwoofer channel of the Marine A5055 is low-pass only.
Selecting the Crossover Frequency
Choose the crossover point to suit listening preferences. Turn the dials to the left to lower the crossover point and to the right to raise it. Exact settings depend on your listening preferences and speaker types.
Selecting the Subwoofer Phase (Marine A5055 Only)
Switch the PHASE control back and forth to determine which setting provides the most clean bass output.
Selecting the Bass Boost (Marine A5055 Only)
Adjust the BASS BOOST control clockwise or counterclockwise to suit your taste.
Specifications
| Marine A754 | Marine A5055 | |
|---|---|---|
| Power output @ 4 ohms (14.4V) | 75 watts RMS x 4 | 50 watts RMS x 4, 320 watts x 1 |
| Power output @ 4 ohms (12V) | 55 watts RMS x 4 | 40 watts RMS x 4, 255 watts x 1 |
| Power output @ 2 ohms (14.4V) | 100 watts RMS x 4 | 75 watts RMS x 4, 500 watts x 1 |
| Power output @ 2 ohms (12V) | 80 watts RMS x 4 | 65 watts RMS x 4, 390 watts x 1 |
| Power output in bridged mode (14.4V) | 200 watts RMS x 2 at 4 ohms | 150 watts RMS x 2 at 4 ohms |
| Power output in bridged mode (12V) | 160 watts RMS x 2 at 4 ohms | 130 watts RMS x 2 at 4 ohms |
| Frequency response | 10-40 KHz | 10-40 KHz / 25-320 Hz |
| Crossover frequencies | 32-320 Hz variable, 12 dB/octave (front and rear) | 32-320 Hz variable high- and low-pass (front and rear); 32-320 Hz low-pass (subwoofer); 12 dB/octave |
| Line-level input sensitivity | 200 mVrms 4 Vrms | 200 mVrms 4 Vrms |
| High-level input sensitivity | 1 22 Vrms | 1 22 Vrms |
| Signal-to-noise ratio | >80 dB | >80 dB |
| THD+N @ rated power | <1% | <1% |
| Fuse rating | 30 A x 2 | 30 A x 3 |
| Dimensions (W x H x D) | 320mm x 51.3mm x 180mm (12-5/8" x 2-1/16" x 7-1/8") | 360mm x 51.3mm x 180mm (14-3/16" x 2-1/16" x 7-1/8") |
| Weight | 3.08 kg | 3.98 kg |
| Recommended wire gauge | 8 | 4 |
| Maximum operation temperature | 45°C | 45°C |
Troubleshooting
No audio and POWER INDICATOR is off.
- No voltage at BATT+ and/or REM terminals, or bad or no ground connection. Check voltages at amplifier terminals with VOM (Volt-Ohm Meter).
No audio and PROTECT INDICATOR flashes every 4 seconds.
- DC voltage on amplifier output. Amplifier may need service; see enclosed warranty card for service information.
No audio and PROTECT and POWER INDICATORS flash.
- Voltage less than 9V on BATT+ connection. Check boat charging system.
No audio and PROTECT INDICATOR is on.
- Amplifier is overheated. Make sure amplifier cooling is not blocked at mounting location. Or, there may be voltage greater than 16V (or less than 8.5V) on BATT+ connection. Check boat charging system.
Amplifier fuse keeps blowing.
- The wiring is connected incorrectly or there is a short circuit. Check wiring connections.
Distorted audio.
- Gain is not set properly. Check setting. Check wires for shorts or grounds. Amplifier or source unit may be defective.
Distorted audio and PROTECT INDICATOR flashes.
- Short circuit in speaker or wire. Remove speaker leads one at a time to locate shorted speaker or wire, and repair.
Music lacks dynamics or "punch".
- Speakers are not connected properly. Check speaker connections for proper polarity.
Engine noise--whining or clicking--in system when the engine is on.
- Amplifier is picking up alternator noise. First, check ground connection on the amplifier – a loose or improper ground is one of the main causes for noise. Turn down gain. Move RCA audio cables away from power wires. Installing an alternator noise filter on power line between battery and alternator might also be necessary.
For further information, refer to HARMAN International Industries, Incorporated, 8500 Balboa Boulevard, Northridge, CA 91329 USA, www.jbl.com.
