Instruction Manual

1. Introduction

The TOA Electronics D-921E is a high-quality 24-bit input module specifically designed for seamless integration with TOA D-901 and DP-K1 digital mixers. This module enhances your audio setup by providing two independent channels for balanced microphone or line-level signals.

Key features of the D-921E include:

• 2-channel, removable terminal block for easy connection.
• High-fidelity 24-bit A/D converter for superior sound quality.
• Integrated 15V phantom power supply for condenser microphones.
• Adjustable input gain to optimize signal levels.
• Individual ground-lift switches for each input to eliminate hum and noise.
• Low Total Harmonic Distortion (THD) of 0.05% or less.

Figure 1: Front view of the TOA D-921E Input Module, showing the two 3-pin phoenix-type connectors, ground lift switches, and the main circuit board. The module is black with green connectors and a green circuit board.

2. Setup and Installation

The D-921E module is designed for easy installation into compatible TOA digital mixers such as the D-901 and DP-K1. Ensure the mixer is powered off before installation.

2.1 Module Installation

1. Power off and unplug your TOA D-901 or DP-K1 digital mixer.
2. Locate an available module slot on your mixer. Refer to your mixer's manual for specific slot locations.
3. Carefully align the D-921E module with the slot and gently push it in until it is securely seated. Ensure the mounting screw is aligned.
4. Secure the module using the provided mounting screw on the front panel.

2.2 Connecting Audio Devices

The D-921E features two 3-pin phoenix-type connectors for audio input. These connectors support both balanced microphone and line-level signals.

• Microphone Input: Connect balanced microphones using appropriate cabling to the phoenix connectors. The module provides 15V phantom power for condenser microphones, which can be enabled or disabled via the mixer's settings (refer to your mixer's manual).
• Line Input: Connect line-level audio sources (e.g., CD players, preamplifiers, other audio equipment) using appropriate balanced cabling to the phoenix connectors.

2.3 Ground Lift Switches

Each input channel on the D-921E is equipped with a ground-lift switch. This switch helps to eliminate hum or buzzing noises caused by ground loops in your audio system.

• NORMAL: In this position, the input ground is connected to the chassis ground. This is the standard setting.
• GND LIFT: In this position, the input ground is disconnected from the chassis ground. Use this setting if you experience hum or noise.

Experiment with the ground lift switch for each channel to find the setting that provides the cleanest audio signal in your specific environment.

3. Operating Instructions

Once the D-921E module is installed and audio devices are connected, you can configure and operate it through your TOA D-901 or DP-K1 digital mixer's interface.

3.1 Input Gain Adjustment

The D-921E allows for adjustable input gain to match the level of your connected audio source. This adjustment is typically performed within the digital mixer's software or front panel controls.

• Refer to your D-901 or DP-K1 mixer's operation manual for detailed instructions on accessing and adjusting input gain settings for the D-921E module's channels.
• Adjust the gain to achieve an optimal signal level without clipping (distortion). Aim for a strong signal that does not peak into the red on the mixer's meters.

3.2 Phantom Power Control

For condenser microphones requiring phantom power, the D-921E provides a 15V supply. This feature is controlled via the connected digital mixer.

• Ensure phantom power is only enabled when using condenser microphones that require it. Applying phantom power to dynamic microphones or line-level devices can cause damage.
• Consult your mixer's manual for instructions on how to enable or disable phantom power for specific input channels.

4. Maintenance

The TOA D-921E input module is designed for reliable operation with minimal maintenance. Follow these guidelines to ensure its longevity:

• Cleaning: Use a soft, dry cloth to clean the exterior of the module. Do not use liquid cleaners, solvents, or abrasive materials, as these can damage the finish or internal components.
• Environment: Operate the module within its specified temperature and humidity ranges. Avoid exposing it to excessive dust, moisture, or direct sunlight.
• Connections: Periodically check all cable connections to ensure they are secure and free from damage.
• Storage: If storing the module for an extended period, keep it in a cool, dry place, ideally in its original packaging or a protective case.

No user-serviceable parts are inside the module. Refer all servicing to qualified TOA service personnel.

5. Troubleshooting

This section provides solutions to common issues you might encounter with the D-921E input module.

If the problem persists after trying these solutions, please contact TOA Electronics customer support or a qualified service technician.

6. Specifications

*0 dB = 1 V

7. Warranty and Support

TOA Electronics products are manufactured to the highest quality standards and are backed by a limited warranty. For specific warranty terms and conditions applicable to your D-921E module, please refer to the warranty card included with your product or visit the official TOA Electronics website.

For technical support, service, or inquiries regarding your TOA D-921E input module, please contact TOA Electronics customer support directly. Contact information can typically be found on the TOA Electronics official website or in your product's packaging.

TOA Electronics Official Website: www.toa-corp.com