1. Introduction and Overview
This manual provides essential information for the safe and efficient operation of your Bosch Plena PLE-1ME120-US Mixer Amplifier. Please read this manual thoroughly before installation and use, and retain it for future reference.
The Bosch Plena Economy mixer amplifiers are professional public address units designed for ease of use. They integrate modern state-of-the-art features to simplify operation, making it straightforward to deliver crisp calls or clear music. This amplifier offers the core functionalities required for public address systems in an accessible and affordable package.
2. Safety Information
Always observe the following safety precautions to prevent electric shock, fire, or damage to the unit:
- Power Source: Connect the unit only to the specified power supply voltage. Ensure the power cord is not damaged or pinched.
- Ventilation: Do not block ventilation openings. Ensure adequate airflow around the unit to prevent overheating. Do not install in a confined space.
- Moisture: Do not expose the unit to rain or moisture. Do not place objects filled with liquids, such as vases, on the unit.
- Foreign Objects: Do not insert any foreign objects into the unit's openings.
- Servicing: Refer all servicing to qualified service personnel. Do not attempt to service this product yourself.
- Grounding: Ensure the unit is properly grounded to prevent electric shock.
- Overload: Do not overload the amplifier. Ensure connected speakers and other equipment match the amplifier's specifications.
3. Package Contents
Verify that all items are present in the package:
- 1 x PLE-1ME120-US Plena Mixer Amplifier
- 1 x Power Cord
- 1 x User Manual (this document)
- 1 x CD-ROM (Plena Easy Line software/documentation)
4. Product Features and Controls
Figure 4.1: Front Panel of the Bosch Plena PLE-1ME120-US Mixer Amplifier
The image above displays the front panel of the Bosch Plena PLE-1ME120-US Mixer Amplifier. Key features visible include the power button, individual volume controls for four microphone inputs (Mic 1-4), a background music (BGM) input volume control, HI and LO tone adjustment knobs, and a master volume control. On the right, there are LED indicators for signal presence and limiter activation, along with a headphone output jack. The top surface features ventilation grilles and the Bosch logo.
Front Panel Controls:
- POWER Button: Toggles the amplifier's power on and off.
- Mic 1-4 Volume Knobs: Adjust the input level for each of the four microphone channels.
- BGM Volume Knob: Adjusts the input level for the Background Music source.
- HI Tone Control: Adjusts the high-frequency response of the mixed audio.
- LO Tone Control: Adjusts the low-frequency response of the mixed audio.
- MASTER VOLUME Knob: Controls the overall output volume of the amplifier.
- LIMITER LED: Illuminates when the internal limiter is active, indicating that the output signal is being compressed to prevent distortion.
- SIGNAL LED: Illuminates when an audio signal is present at the output.
- Headphone Jack: 3.5mm stereo output for monitoring the mixed audio signal.
5. Setup
5.1 Placement and Ventilation
Place the amplifier on a stable, flat surface. Ensure there is at least 10 cm (4 inches) of clear space around all sides of the unit for proper ventilation. Do not place the amplifier near heat sources or in direct sunlight.
5.2 Connecting Audio Inputs
- Microphones: Connect your microphones to the appropriate input jacks on the rear panel (not visible in the provided image, but standard for mixer amplifiers). Ensure correct cable types (e.g., XLR or TRS) are used.
- Background Music (BGM): Connect your audio source (e.g., CD player, media player) to the BGM input. Use appropriate RCA or TRS cables.
5.3 Connecting Audio Outputs (Speakers)
Connect your speakers to the amplifier's output terminals on the rear panel. Ensure the speaker impedance matches the amplifier's output impedance (typically 4 Ohm or 8 Ohm, or 70V/100V line for public address systems). Incorrect impedance can damage the amplifier or speakers.
5.4 Power Connection
After all audio connections are made, connect the supplied power cord to the amplifier's power inlet and then to a suitable AC power outlet. Ensure the power outlet is grounded.
6. Operating Instructions
6.1 Powering On/Off
- To power on, press the POWER button. The power indicator (if present, typically on the front panel) will illuminate.
- To power off, press the POWER button again.
6.2 Adjusting Input Levels
- Set all Mic 1-4 and BGM volume knobs to their minimum position (fully counter-clockwise) before starting.
- Gradually increase the volume knob for the desired microphone or BGM source while speaking into the microphone or playing music.
- Adjust each input level until the SIGNAL LED flickers consistently during normal operation, but the LIMITER LED rarely illuminates.
6.3 Tone Control Adjustment
- Use the HI control to adjust the treble frequencies. Turn clockwise for more brightness, counter-clockwise for a softer sound.
- Use the LO control to adjust the bass frequencies. Turn clockwise for more bass, counter-clockwise for less bass.
- Adjust these controls to suit your preference and the acoustics of the room.
6.4 Master Volume Control
Once individual input levels are set, use the large MASTER VOLUME knob to control the overall output volume of the amplifier. Adjust this to the desired listening level for your audience.
6.5 Headphone Monitoring
Plug 3.5mm headphones into the headphone jack to monitor the mixed audio signal without affecting the main output. The headphone volume is typically linked to the Master Volume or has its own dedicated control (not explicitly shown but common).
7. Maintenance
- Cleaning: Disconnect the power 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. Use a soft brush or compressed air to gently clean them.
- Storage: If storing the amplifier for an extended period, ensure it is in a cool, dry place, away from direct sunlight and extreme temperatures.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No power | Power cord disconnected; Power outlet faulty; Unit fuse blown. | Check power cord connection; Test power outlet; Consult qualified service personnel for fuse replacement. |
| No sound output | Master volume too low; Input volume too low; Speaker connections faulty; Speakers damaged. | Increase MASTER VOLUME; Increase individual input volumes; Check speaker wiring; Test speakers with another amplifier if possible. |
| Distorted sound | Input signal too high (clipping); Master volume too high; Speaker impedance mismatch. | Reduce input volume until LIMITER LED rarely illuminates; Reduce MASTER VOLUME; Verify speaker impedance matches amplifier. |
| Hum or noise | Ground loop; Poor cable shielding; Nearby electrical interference. | Ensure proper grounding; Use high-quality shielded cables; Move amplifier away from other electronic devices. |
9. Specifications
| Parameter | Value |
|---|---|
| Model | PLE-1ME120-US |
| RMS Output Power | 120 W |
| Audio Channels | 4 (Microphone inputs) |
| Minimum Frequency Response | 60 Hz |
| Maximum Frequency Response | 20 kHz |
| Operating Power Consumption | 400 W |
| Color | Charcoal |
| Dimensions (H x W x D) | 3.9" x 16.9" x 10.6" (approx. 9.9 cm x 42.9 cm x 26.9 cm) |
| Weight (Approximate) | 19.62 lb (approx. 8.9 kg) |
| Manufacturer | Bosch |
10. Warranty and Support
For warranty information and technical support, please refer to the warranty card included with your product or contact your authorized Bosch (Electro-Voice) dealer or distributor. Do not attempt to repair the unit yourself, as this may void your warranty.
You can also visit the official Electro-Voice website for further support and resources: www.electrovoice.com
