Nobsound NS-13G-MAX HiFi 2-Channel TPA3255 Phono Stereo Audio Amplifier User Manual

1. Introduction

The Nobsound NS-13G-MAX is a high-fidelity 2-channel stereo audio amplifier designed for audiophiles. It features a TPA3255 amplifier chip, delivering up to 300W per channel, and supports both MM phono and stereo RCA inputs. This amplifier offers flexible audio customization with tone controls and a bypass switch, making it suitable for a wide range of audio setups, from turntables to digital media players.

Figure 1: Nobsound NS-13G-MAX HiFi Amplifier

2. Setup

2.1 Unpacking Contents

Carefully unpack the amplifier and check for the following items:

• 1x NS-13G MAX Amplifier
• 1x DC 48V/5A Power adapter (optional, depending on purchase)

2.2 Connecting Your Audio System

Refer to the diagram below for proper connection of your audio sources and speakers.

Figure 2: Front and Rear Panel Layout with Connection Points

1. Power Connection: Connect the DC 24-48V power adapter (if included or purchased separately) to the DC IN port on the rear panel.
2. Audio Input (RCA / PHONO):
   • For turntables with MM cartridges, connect to the "PHONO IN" RCA jacks.
   • For other audio sources (CD/DVD players, TV, laptops, MP3 players, phones, tablet PCs), connect to the "RCA IN" RCA jacks.
3. Speaker Output: Connect your passive speakers to the "SPK OUT" banana speaker jacks on the rear panel. Ensure correct polarity (+ to + and - to -).
4. AUX Output (Optional): Use the 3.5mm AUX OUT jack to connect to another amplifier, active speakers, or an active subwoofer for a 2.1 or multi-channel audio system.

Note:

• The 3.5mm AUX output and the speaker jacks output are controlled by the main volume and bass/treble synchronously.
• The amplifier is compatible with most audio devices, including turntables, laptops, computers, CD/DVD players, and TVs.

Figure 3: Device Compatibility Overview

3. Operating Instructions

3.1 Front Panel Controls

Figure 4: Front Panel Controls

• RCA / PHONO input switch / Power OFF: This switch selects between RCA and PHONO inputs. The center position acts as the Power OFF switch.
• Power Indicator: Illuminates when the unit is powered on.
• Tone/Bypass mode switch: Engages or bypasses the tone control circuit. In bypass mode, the audio signal is unprocessed for maximum clarity.
• Bass knob: Adjusts the low-frequency response (±6dB).
• Treble knob: Adjusts the high-frequency response (±6dB).
• Volume knob: Controls the overall output volume.

3.2 Basic Operation

1. Ensure all connections are secure before powering on.
2. Set the "RCA / PHONO input switch" to the desired input (RCA or PHONO).
3. Turn the "Volume knob" to its minimum position.
4. Flip the "RCA / PHONO input switch / Power OFF" to either RCA or PHONO to power on the unit. The power indicator will light up.
5. Start playing audio from your selected source.
6. Slowly increase the "Volume knob" to your desired listening level.
7. Adjust "Bass" and "Treble" knobs to fine-tune the sound. For a pure, unprocessed audio signal, set the "Tone/Bypass mode switch" to BYPASS.

4. Maintenance

4.1 Cleaning

To clean the amplifier, use a soft, dry cloth. Do not use liquid cleaners or solvents, as they may damage the finish or internal components.

4.2 Heat Dissipation

The NS-13G-MAX features an innovative heat dissipation design with strategically placed side and bottom vents. To ensure optimal performance and extend the device's lifespan, ensure these vents are not obstructed. Avoid placing the amplifier in enclosed spaces without adequate airflow.

Figure 5: Innovative Heat Dissipation Design

4.3 Op-Amp Replacement

The amplifier features a pluggable op-amp socket, allowing for customization. The NE5532P op amp can be replaced by most dual op-amps such as OPA2604, OPA2134, MUSE02, etc. Exercise caution when replacing op-amps to avoid damaging the pins or the socket. Ensure the device is powered off and unplugged before attempting any component replacement.

Figure 6: High-Quality Audio Components including Pluggable Op-Amp

5. Troubleshooting

• No Power:
  • Check if the power adapter is securely connected to both the amplifier and a working power outlet.
  • Ensure the power switch (RCA/PHONO input switch in OFF position) is correctly set to an input to power on.
• No Sound:
  • Verify that the correct input (RCA or PHONO) is selected.
  • Check all audio cable connections between the source, amplifier, and speakers.
  • Ensure the volume knob is turned up.
  • Confirm that your audio source is playing and its volume is not muted or too low.
• Distorted Sound:
  • Reduce the volume from both the source and the amplifier.
  • Check for loose or damaged speaker wires.
  • Ensure the impedance of your speakers matches the amplifier's output impedance range (4Ω-8Ω).

6. Specifications

6.1 Power Output Table

7. User Tips

• For optimal sound quality, experiment with the "Tone/Bypass mode switch" to see if you prefer the sound with or without tone adjustments.
• When replacing op-amps, ensure the new op-amp is compatible and correctly oriented in the socket. Refer to the op-amp's datasheet for pin configuration.
• Consider using high-quality audio cables and speaker wires to minimize signal loss and interference.
• Place the amplifier on a stable, level surface away from direct sunlight, heat sources, and excessive moisture.

8. Warranty & Support

8.1 Warranty Information

This Nobsound NS-13G-MAX amplifier comes with a 2-year warranty from the date of purchase, covering manufacturing defects. Please retain your proof of purchase for warranty claims.

8.2 Customer Support

For technical assistance, troubleshooting, or warranty inquiries, please contact Nobsound customer support through their official channels. Provide your model number (NS-13G-MAX) and a detailed description of the issue for faster service.