1. Introduction
Thank you for choosing the Douk Audio NS-13G-MAX HiFi 2.0 Channel Stereo Audio Amplifier. This mini digital power amplifier features a TPA3255 chip, delivering 300W+300W output, and includes both MM Phono and stereo RCA inputs. It is designed for audiophiles seeking high-fidelity sound in a compact and stylish form factor. This manual provides essential information for setting up, operating, maintaining, and troubleshooting your amplifier to ensure optimal performance and longevity.
2. Safety Information
Please read and understand the following safety precautions before operating the device:
- Ensure the power supply voltage matches the requirements of the amplifier (DC 24-48V).
- Do not expose the device to water, moisture, or extreme temperatures.
- Avoid placing the amplifier in direct sunlight or near heat sources.
- Do not open the amplifier casing; there are no user-serviceable parts inside. Refer all servicing to qualified personnel.
- Keep the device away from children and pets.
- Disconnect the power adapter before making any connections or cleaning the unit.
- Ensure proper ventilation around the amplifier to prevent overheating.
3. Package Contents
Please check the package for the following items:
- 1x NS-13G MAX Amplifier
- 1x DC 48V/5A Power adapter (optional, depending on your purchase)
4. Product Overview
The NS-13G-MAX amplifier features a robust and stylish aluminum case with strategically placed vents for heat dissipation. Below is an overview of its front and rear panels.
Front Panel Controls:
- RCA / PHONO input switch / Power OFF: Selects between RCA and Phono inputs, and also serves as the power switch.
- Tone/Bypass mode switch: Engages or bypasses the tone control circuit.
- Bass knob: Adjusts low-frequency output.
- Treble knob: Adjusts high-frequency output.
- Volume knob: Controls the overall output volume.
Rear Panel Connections:
- RCA IN: Standard stereo RCA input for line-level sources.
- PHONO IN: RCA input specifically for MM (Moving Magnet) turntables.
- AUX OUT (3.5mm): 3.5mm stereo output for connecting to another amplifier or active speaker/subwoofer.
- SPK OUT (Speaker output): Banana speaker jacks for connecting passive speakers.
- DC 24V-48V: Power input for the DC power adapter.
5. Setup
Follow these steps to set up your NS-13G-MAX amplifier:
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Connect Audio Sources:
- For Turntables (MM Phono): Connect your turntable's RCA output cables to the "PHONO IN" jacks on the amplifier's rear panel. Ensure your turntable has a built-in MM phono preamp or use an external one if needed.
- For other Audio Devices (RCA): Connect your CD/DVD player, TV, laptop, or other audio source's RCA output cables to the "RCA IN" jacks on the amplifier's rear panel.
-
Connect Speakers:
- Connect your passive speakers to the "SPK OUT" banana speaker jacks on the rear panel. Ensure correct polarity (+ to + and - to -) for each speaker.
- Optional: Connect Active Speakers/Subwoofer: If you wish to connect an additional amplifier or active speaker/subwoofer, use a 3.5mm audio cable from the "AUX OUT" jack to the input of your external device. Note that the AUX output is controlled synchronously with the main volume and tone controls.
-
Connect Power:
- Ensure the amplifier's power switch is in the "OFF" position.
- Connect the DC power adapter to the "DC 24V-48V" input on the rear panel.
- Plug the power adapter into a suitable wall outlet.
6. Operating Instructions
-
Power On:
Turn the RCA / PHONO input switch to either "RCA" or "PHONO" to power on the amplifier.
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Select Input:
Use the RCA / PHONO input switch to select the desired audio source (e.g., "PHONO" for your turntable or "RCA" for other devices).
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Adjust Volume:
Rotate the "VOL" knob clockwise to increase the volume and counter-clockwise to decrease it. Start with a low volume and gradually increase it to a comfortable listening level.
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Tone Control:
- Bass/Treble Knobs: Use the "BASS" and "TREBLE" knobs to fine-tune the low and high frequencies of your audio.
- Tone/Bypass Switch: Flip the "TONE/BYPASS" switch to "TONE" to enable the bass and treble controls. Flip it to "BYPASS" to disable tone controls and obtain pure, unprocessed audio.
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Power Off:
Turn the RCA / PHONO input switch to the "OFF" position to power off the amplifier.
Note: The 3.5mm AUX output and the speaker jacks output are controlled by the main volume and bass/treble synchronously.
7. Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the amplifier. Do not use liquid cleaners or solvents.
- Ventilation: Ensure the side and bottom vents are clear of obstructions to maintain proper heat dissipation. The innovative heat dissipation design helps prevent dust accumulation, but regular checks are recommended.
- Op-Amp Replacement: The NE5532P op amp is pluggable and can be replaced by most dual op-amps such as OPA2604, OPA2134, or MUSE02 for sound customization. Exercise caution and refer to specialized guides if performing this modification.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound output |
|
|
| Distorted sound |
|
|
| No Phono input sound |
|
|
9. Specifications
General Parameters:
- Audio Inputs: RCA / MM Phono
- Audio Outputs: Banana speaker jacks / 3.5mm AUX
- Amplifier Chip: TPA3255
- Max Output Power: 300W*2 (at 4Ω)
- Output Impedance: 4Ω-8Ω
- Bass & Treble Adjustment Range: ±6dB
- Input Sensitivity: Phono: 5mV, RCA: 2V
- THD+N: 0.005% @ 1kHz
- SNR: ≥107dB
- AUX Output Level: 2.4V
- Frequency Response: 20Hz-20KHz (±1dB)
- Working Voltage: DC 24-48V
- Dimensions (W*D*H): 130*102*38mm / 5.12*4.02*1.50in
- Net Weight: 513g / 1.13lb
- Package Weight (with 48V5A power supply): 1.3kg / 2.87lb
Power Output Table of NS-13G MAX:
| Power Supply | Speaker Impedance | Rated Output Power |
|---|---|---|
| 32V/5A | 4Ω | 78W+78W |
| 6Ω | 71W+71W | |
| 8Ω | 65W+65W | |
| 48V/5A | 4Ω | 120W+120W |
| 6Ω | 110W+110W | |
| 8Ω | 102W+102W | |
| 48V/10A | 4Ω | 250W+250W |
| 6Ω | 210W+210W | |
| 8Ω | 185W+185W |
10. User Tips
- Power Supply Upgrade: For users seeking higher power output, consider acquiring a separate, high-quality 48V/10A power adapter. This can significantly boost the amplifier's performance, especially with lower impedance speakers.
- Synchronized Output Control: Remember that both the main speaker outputs and the 3.5mm AUX output are controlled simultaneously by the main volume, bass, and treble knobs. Plan your audio setup accordingly if using the AUX out for active speakers or a subwoofer.
- Op-Amp Rolling: The pluggable op-amp socket allows for easy experimentation with different dual op-amps (e.g., OPA2604, OPA2134, MUSE02) to customize the sound signature to your preference. Ensure the amplifier is powered off and unplugged before attempting to replace the op-amp.
- Optimal Placement: Place the amplifier on a stable, flat surface with adequate space around it for proper airflow to utilize its innovative heat dissipation design effectively.
11. Warranty and Support
For warranty information, technical support, or service inquiries, please contact your retailer or the manufacturer directly. Keep your purchase receipt as proof of purchase.
Manufacturer: Douk Audio
