1. Introduction
This manual provides essential information for the safe and efficient operation of your TOA A-848D Mixer/Digital Amplifier. Please read this manual thoroughly before use and retain it for future reference. The A-848D is a versatile mixer amplifier designed for various audio applications, offering up to eight inputs and 480W of power, with features like IP control and onboard DSP.
2. Important Safety Instructions
- Power Source: Connect the unit only to a 120 V AC, 60 Hz power supply. Ensure the power cord is securely plugged in.
- Ventilation: Do not block ventilation openings. Ensure adequate airflow around the unit to prevent overheating.
- Moisture: Do not expose the unit to rain or moisture. Avoid placing objects filled with liquids, such as vases, on the apparatus.
- Foreign Objects: Do not insert any objects into the unit's openings.
- Servicing: Refer all servicing to qualified service personnel. Do not attempt to service this product yourself.
- Grounding: Ensure proper grounding to prevent electric shock.
3. Package Contents
Verify that all items are present in the package:
- TOA A-848D Mixer/Digital Amplifier
- Power Cord
- Removable Terminal Blocks (various sizes for inputs/outputs)
- User Manual (this document)
4. Product Overview
4.1 Front Panel
Figure 4.1: Front Panel of the TOA A-848D. This image displays the front of the amplifier, featuring six input level controls, two module level controls, Bass and Treble tone controls, a Master volume knob, and a power button. An LED display shows output levels, and status indicators for Error, Over Current, Thermal Protect, LAN Connect, Emergency, Priority, and CPU Run are visible.
- INPUT 1-6 Level Controls: Adjust the input level for each of the six audio inputs.
- MODULE 1-2 Level Controls: Adjust the input level for optional 900 Series modules.
- BASS/TREBLE Tone Controls: Adjust the low and high frequency response of the output.
- MASTER Volume Control: Adjust the overall output volume.
- Power Button: Turns the unit on or off.
- LED Level Meter: Displays the output signal level.
- Status Indicators: LEDs for Error, Over Current, Thermal Protect, LAN Connect, Emergency, Priority, and CPU Run.
4.2 Rear Panel
Figure 4.2: Rear Panel of the TOA A-848D. This image shows the rear connections, including the AC power inlet, speaker outputs, remote control terminals, various input terminals (MIC/LINE, phantom power switches), LAN port, pre-amp out, and slots for two 900 Series modules. Dip switches for module settings are also visible.
- AC Power Inlet: Connect the supplied power cord here.
- Speaker Outputs: Terminals for connecting loudspeakers.
- POWER REMOTE OUT: For remote power control.
- EMERGENCY OUT: For emergency system integration.
- INPUT 1-4 (MIC/LINE): Electronically-balanced removable terminal blocks. Phantom power (24V DC) is switchable for INPUT 1-4.
- INPUT 5-6 (MIC/LINE/RCA): Electronically-balanced removable terminal blocks for MIC, or unbalanced RCA pin jacks for LINE.
- LAN Port: For network connection and IP control.
- REC OUT: RCA output for recording.
- PRE AMP OUT: RCA output for connecting to an external power amplifier.
- MODULE 1-2 Slots: Bays for installing optional 900 Series modules.
- DIP Switches: Various switches for configuring module functions, phantom power, and input types.
5. Setup and Installation
- Placement: Place the amplifier on a stable, level surface with adequate ventilation. Avoid direct sunlight, heat sources, and excessive dust or moisture.
- Speaker Connection: Connect your loudspeakers to the appropriate speaker output terminals on the rear panel. Ensure correct polarity (+ to + and - to -). Refer to the speaker impedance and power handling specifications.
- Input Device Connection:
- For microphones or line-level devices, connect to INPUT 1-6 using the removable terminal blocks.
- If using condenser microphones, activate the phantom power switch for the corresponding input on the rear panel.
- For line-level devices with RCA outputs, use INPUT 5 or 6 RCA jacks.
- Module Installation (Optional): If using 900 Series modules, carefully insert them into MODULE 1 or 2 slots on the rear panel. Configure the associated DIP switches as required by the module's instructions.
- Network Connection (Optional): For IP control and monitoring, connect an Ethernet cable from your network router/switch to the LAN port.
- Power Connection: Ensure all audio connections are made before connecting the power cord. Plug the supplied power cord into the AC Power Inlet on the rear panel, then into a suitable 120 V AC, 60 Hz wall outlet.
6. Operating Instructions
- Power On: Press the Power button on the front panel. The unit's indicators will illuminate.
- Initial Volume Settings: Before playing audio, set all INPUT level controls and the MASTER volume control to their minimum positions.
- Adjusting Input Levels:
- Start playing audio from your source device.
- Slowly increase the corresponding INPUT level control until the LED level meter shows a healthy signal without clipping (avoiding the red segment).
- Adjusting Master Volume: Once individual input levels are set, slowly increase the MASTER volume control to achieve the desired overall output level.
- Tone Control: Use the BASS and TREBLE controls to fine-tune the audio's low and high frequencies to suit your preference or room acoustics.
- IP Control (if connected): Access the amplifier's web interface via its IP address (refer to network setup instructions for details) to configure advanced settings, monitoring, and remote control.
- Power Off: To turn off the unit, press the Power button.
7. Maintenance
- Cleaning: Disconnect the power cord before cleaning. Use a soft, dry cloth to wipe the exterior of the unit. Do not use liquid cleaners or aerosols.
- Ventilation: Periodically check that the ventilation openings are clear of dust and debris.
- Storage: If storing the unit for an extended period, disconnect it from power and store it in a cool, dry place.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No power | Power cord not connected; Power outlet faulty; Unit fuse blown. | Check power cord connection; Try a different outlet; Contact service personnel for fuse replacement. |
| No sound output | Master volume too low; Input level too low; Speaker connections incorrect; Mute function active; Source device not playing. | Increase Master volume; Increase input level; Check speaker wiring and polarity; Check for mute settings (if applicable); Verify source device operation. |
| Distorted sound | Input level too high (clipping); Speaker impedance mismatch; Faulty cable. | Reduce input level; Ensure speaker impedance matches amplifier; Replace audio cables. |
| Hum or noise | Ground loop; Poor cable shielding; Nearby electrical interference. | Ensure proper grounding; Use shielded cables; Move unit away from interference sources. |
| Thermal Protect LED active | Unit overheating due to blocked ventilation or excessive load. | Turn off unit, allow to cool; Ensure ventilation is clear; Reduce output load if possible. |
If the problem persists after attempting these solutions, please contact qualified service personnel.
9. Specifications
| Feature | Detail |
|---|---|
| Model | A-848D |
| Power Source | 120 V AC, 60 Hz |
| Rated Output | 480 W |
| Power Consumption | 621 W (rated output), 103 W (UL62368), 200 mA or less (power OFF) |
| Frequency Response | 50 Hz to 20 kHz ±3 dB (1/8 rated output) |
| Distortion | 1 % or less at 1 kHz, rated power |
| Tone Control | Bass: ±10 dB at 100 Hz, Treble: ±10 dB at 10 kHz |
| Signal to Noise Ratio | 88 dB or more (Master min), 76 dB or more (Master max), 55 dB or more (INPUT 1 to 6) (A-weighted) |
| Inputs 1, 2 | -60 dB (MIC)/-20 dB (LINE) selectable, 600 Ω, electronically-balanced, removable terminal block (3.81 mm, 3 pins). Phantom power (24 V DC, ON/OFF switchable). |
| Inputs 3, 4 | -60 dB, 600 Ω, electronically-balanced, removable terminal block (3.81 mm, 3 pins). Phantom power (24 V DC, ON/OFF switchable). |
| Inputs 5, 6 | MIC: -60 dB, 600 Ω, electronically-balanced, removable terminal block (3.81 mm, 3 pins). LINE: -20 dB, 10 kΩ, unbalanced, RCA pin jack x 2. |
| Operating Humidity | 85 % RH or less (no condensation) |
| Finish | Panel: ABS resin, black |
| Item Weight | 11.9 pounds |
| Number of Channels | 8 |
| Connectivity Technology | Auxiliary |
10. Warranty and Support
For warranty information and technical support, please refer to the documentation provided with your purchase or visit the official TOA website. Do not attempt to repair the unit yourself, as this may void your warranty.
