1. Introduction
This manual provides detailed instructions for the proper setup, operation, and maintenance of your jindaaudio 4-Channel Audio Mixer Sound Board, Model 4Ch-A4 99DSP. This professional audio mixer features 4 input channels, a USB audio interface, Bluetooth connectivity, 48V phantom power, and 99 DSP effects. Please read this manual thoroughly before using the device to ensure optimal performance and safety.

The compact design of the jindaaudio 4-Channel Audio Mixer allows for easy portability.
2. Safety Instructions
- Power Supply: Use only the provided power adapter. Ensure the voltage matches the requirements specified on the device.
- Water and Moisture: Do not expose the mixer to water, rain, or excessive moisture. Avoid placing liquid-filled objects on the unit.
- Ventilation: Ensure adequate ventilation around the unit. Do not block ventilation openings.
- Heat Sources: Keep the mixer away from heat sources such as radiators, heat registers, stoves, or other heat-producing appliances.
- Cleaning: Disconnect the power before cleaning. Use a dry, soft cloth. Do not use liquid cleaners or aerosol cleaners.
- Servicing: Do not attempt to service this product yourself. Refer all servicing to qualified service personnel.
- 48V Phantom Power: When using 48V phantom power, ensure that condenser microphones are connected before activating the phantom power to prevent damage to other equipment.
3. Package Contents
Please check that all items are present in the package:
- jindaaudio 4-Channel Audio Mixer (Model: 4Ch-A4 99DSP)
- Power Adapter
- USB Cable
- User Manual (this document)
4. Product Overview
The jindaaudio 4-Channel Audio Mixer features a user-friendly layout with various inputs, outputs, and controls for versatile audio mixing.

Detailed view of the mixer's top panel, highlighting input/output ports and control knobs.
4.1 Front Panel Controls and Interfaces
- MIC/LINE Inputs (Channels 1-2): XLR/TRS combo jacks for microphones or line-level instruments.
- HI-Z Switch: For high-impedance instruments like guitars on Channels 1-2.
- +48V Phantom Power Switch: Activates 48V phantom power for condenser microphones on Channels 1-2.
- LINE Inputs (Channels 3/4): TRS/RCA inputs for stereo line-level devices.
- GAIN Knobs: Adjust input sensitivity for each channel.
- HIGH/LOW EQ Knobs: Treble and Bass equalization for each channel.
- FX Knobs: Adjust the amount of effect sent from each channel.
- LEVEL Knobs: Adjust the output level of each channel.
- PEAK LED: Indicates when the input signal is too high.
- USB/Bluetooth Interface: USB port for computer connection and media playback, Bluetooth for wireless audio streaming.
- DSP Effects Processor: Digital display and controls (PROGRAM, PREV, NEXT, P/P, MODE) for selecting and adjusting 99 built-in effects.
- STEREO OUT: XLR outputs for connecting to main speakers or amplifiers.
- PHONES: 1/4" stereo jack for headphone monitoring.
- OUT LEVEL: Master output level control.
- PHONES LEVEL: Headphone output level control.
4.2 Rear Panel Interfaces
- DC IN (12V): Power input jack for the supplied AC adapter.
- Power Switch: Turns the unit on or off.

Dimensions of the mixer, showing its compact footprint.
5. Setup
5.1 Power Connection
- Ensure the mixer's power switch is in the OFF position.
- Connect the supplied AC power adapter to the DC IN (12V) jack on the rear panel of the mixer.
- Plug the power adapter into a suitable electrical outlet.
- Turn on the mixer using the power switch. The power indicator LED will illuminate.

Connect the supplied AC power adapter to the DC IN (12V) jack.
5.2 Initial Connections
Before turning on any connected devices, ensure all volume levels on the mixer are set to minimum.
- Microphones: Connect dynamic or condenser microphones to the MIC/LINE inputs (Channels 1-2) using XLR cables. If using a condenser microphone, ensure 48V phantom power is enabled after connection.
- Instruments: Connect instruments like guitars or keyboards to the MIC/LINE inputs (Channels 1-2) using 1/4" TRS cables. For high-impedance instruments, activate the HI-Z switch.
- Line-Level Devices: Connect CD players, media players, or other line-level devices to the LINE inputs (Channels 3/4) using 1/4" TRS or RCA cables.
- Main Output: Connect the STEREO OUT (XLR) to your power amplifier or active speakers.
- Headphones: Connect your headphones to the PHONES 1/4" jack for monitoring.

The mixer supports diverse connections for various audio devices.
6. Operating Instructions
6.1 Adjusting Input Levels
- Ensure all channel LEVEL knobs and the main OUT LEVEL knob are at their minimum.
- For the desired input channel, slowly increase the GAIN knob until the PEAK LED flashes only occasionally during the loudest parts of the signal.
- Adjust the channel LEVEL knob to balance the volume with other inputs.
6.2 Using 48V Phantom Power
The mixer provides 48V phantom power for condenser microphones on Channels 1 and 2.
- Connect your condenser microphone to the MIC/LINE input.
- Press the +48V phantom power switch. The corresponding LED will illuminate.
- Caution: Do not activate 48V phantom power when dynamic microphones or other non-phantom powered devices are connected, as this may cause damage.

The 48V phantom power supply is essential for condenser microphones.
6.3 Bluetooth Connectivity
- Press the MODE button on the DSP section until 'BT' appears on the digital display.
- On your Bluetooth device (smartphone, tablet), search for available devices and select 'BT-AUDIO'.
- Once paired, audio from your device will play through the mixer. Use the P/P (Play/Pause), PREV (Previous), and NEXT (Next) buttons to control playback.
6.4 USB Audio Interface and Playback
The mixer can connect to a computer via USB for recording and playback, and also supports USB flash drive playback.
- USB Flash Drive Playback: Insert a USB flash drive containing MP3 files into the USB port. The mixer will automatically detect and begin playing audio. Use the P/P, PREV, and NEXT buttons for control.
- Computer Connection: Connect the mixer to your computer using a USB cable. The mixer will be recognized as an audio input/output device. You can then use it for recording audio from the mixer or playing audio from your computer through the mixer.

The audio mixer is compatible with USB flash drives and computers for versatile audio input and output.
6.5 DSP Effects
The mixer includes a 99 DSP effects processor for adding reverb, delay, and other effects to your audio.
- Turn the PROGRAM knob to select one of the 99 available effects. The effect number will be displayed.
- Use the FX knob on each channel to send a portion of that channel's signal to the effects processor.
- Adjust the main FX level (if available, typically integrated with the DSP section) to control the overall effect return level.
6.6 Equalization (EQ)
Each channel features HIGH and LOW EQ knobs to shape the tone of your audio. Turn the HIGH knob clockwise to boost treble frequencies and counter-clockwise to cut them. Similarly, use the LOW knob for bass frequencies.

The mixer in use during a recording or live streaming session.
7. Maintenance
- Cleaning: Regularly wipe the mixer's surface with a soft, dry cloth. Avoid using abrasive cleaners or solvents.
- Storage: When not in use, store the mixer in a cool, dry place, away from direct sunlight and extreme temperatures.
- Cable Management: Ensure cables are not tangled or stressed to prevent damage to connectors and ports.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound output |
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| Distorted sound |
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| Bluetooth not connecting |
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| 48V Phantom Power not working |
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9. Specifications
- Model Number: 4Ch-A4 99DSP
- Number of Channels: 4
- Connectivity Technology: XLR, TRS, RCA, USB, Bluetooth
- Phantom Power: +48V (switchable on Channels 1-2)
- DSP Effects: 99 built-in reverb and delay effects
- Power Source: Corded Electric (12V DC)
- Item Weight: 1.5 pounds (approx. 0.68 kg)
- Package Dimensions: 9.7 x 8.5 x 2.5 inches (approx. 24.6 x 21.6 x 6.35 cm)
10. Warranty and Support
For warranty information or technical support, please refer to the documentation included with your purchase or contact jindaaudio customer service through the retailer where the product was purchased. Keep your proof of purchase for warranty claims.