1. Introduction
The Nobsound A5 is a high-fidelity Class D stereo amplifier designed to deliver powerful and clear audio for your home stereo or desktop setup. Featuring the TPA3255 chip, an adjustable high-pass filter, and customizable op-amps, it offers exceptional sound quality and flexibility. This manual provides detailed instructions for setting up, operating, and maintaining your A5 amplifier.
2. Key Features
- HiFi Sound with Adjustable High-Pass Filter (HPF): Refines mid-high frequencies and minimizes low-frequency interference (30-200Hz).
- Easy Customization with Plug-and-Play Op-Amps: Tempered glass access panel allows quick op-amp replacements (e.g., 2134/2604/5532/2068/muse02) for tailored sound profiles.
- PFFB Technology and High-Performance PCB: Post-Filter Feedback technology circuit and a 4-layer immersion gold PCB reduce distortion, improve frequency response, and ensure efficient heat management.
- Stunning Design: Compact with a transparent panel and adjustable internal LED lighting for a modern aesthetic.
- Powerful Output: 300W×2 stereo power (4Ω) with ultra-low THD (0.002%) using the TPA3255 chip.
3. Package Contents
Please check the box for the following items:
- 1x A5 Amplifier
- 1x User Manual
- 1x DC 32V/5A Power Adapter (Optional, depending on purchase)
- 1x DC 48V/5A Power Adapter (Optional, depending on purchase)
4. Setup Instructions
Follow these steps to connect your Nobsound A5 amplifier to your audio system.
4.1 Connecting Audio Sources
- Ensure the amplifier is turned off and unplugged from the power source.
- Connect your audio source (e.g., Tablet PC, iPhone/Android Devices, CD/DVD/Media Players, TV/TV Set Top Box, Laptop/Mac/Computer, MP3 player) to the RCA Input jacks on the rear panel of the A5 amplifier using appropriate RCA cables.
4.2 Connecting Speakers
- For passive speakers, connect them to the Speaker Output terminals on the rear panel using banana plugs or bare wire. Ensure correct polarity (+ to + and - to -).
- For active speakers or an active subwoofer, connect them to the PRE OUT (3.5mm AUX) jack on the rear panel.
4.3 Power Connection
- Connect the DC power adapter (24-48V) to the DC IN port on the rear panel.
- Plug the power adapter into a suitable wall outlet.
5. Operating Instructions
5.1 Power On/Off and Volume Control
The right knob on the front panel controls both power and volume. Rotate it clockwise to turn on the amplifier and increase volume, and counter-clockwise to decrease volume and turn off the amplifier.
5.2 High-Pass Filter (HPF) Adjustment
The left knob on the front panel adjusts the high-pass filter. This allows you to set a cutoff frequency between 30Hz and 200Hz. Adjusting the HPF helps to refine mid-high frequencies and minimize low-frequency interference, especially when using bookshelf speakers or integrating with a subwoofer.
5.3 Op-Amp Rolling (Customization)
The Nobsound A5 features a tempered glass access panel, allowing for easy replacement of the two NE5532 op-amps. This "plug-and-play" design enables audiophiles to experiment with different dual op-amps (e.g., 2134, 2604, 2068, or Muse02) to customize the sound profile without needing to disassemble the unit or use soldering tools.
5.4 LED Ambiance Control
The amplifier is equipped with internal LED lighting visible through the transparent top panel. This lighting offers multiple color options (R, G, B, R+G, R+B, G+B, RGB) to enhance the aesthetic of your audio setup. Specific controls for changing LED colors are typically located internally via switches or jumpers, or may be automatic. Refer to the visual guide for available color combinations.
6. Maintenance
6.1 Heat Dissipation
The Nobsound A5 features advanced full-body heat dissipation to ensure long-term and stable high-power output. It is normal for the casing to heat up during operation, especially during extended use or at high volumes. Ensure adequate ventilation around the amplifier to prevent overheating.
6.2 General Care
- Keep the amplifier clean by wiping it with a soft, dry cloth.
- Avoid exposing the unit to direct sunlight, high temperatures, humidity, or dust.
- Do not block the ventilation holes on the casing.
7. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound output |
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| Distorted sound |
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| Amplifier feels hot |
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| No Bluetooth connectivity | The Nobsound A5 amplifier does not feature built-in Bluetooth functionality. | This model is designed for wired connections (RCA input). If Bluetooth is desired, an external Bluetooth receiver can be connected to the RCA input. |
8. Specifications
| Parameter | Value |
|---|---|
| Brand | Douk Audio |
| Model | A5 |
| Audio Input | Stereo RCA |
| Audio Output | Banana speaker jacks / 3.5mm AUX (PRE OUT) |
| High-Pass Filter Adjustment Range | 30Hz-200Hz |
| Max. Output Power | 300W*2 (4Ω) |
| Matched Speaker Impedance | 4-8Ω |
| THD+N | 0.002% |
| SNR | ≥114dB |
| Input Sensitivity | 2V |
| AUX Rated Output Level | 3.7V |
| Frequency Response | 20Hz-20kHz (±0.7dB) |
| Working Voltage | DC 24-48V |
| Dimensions (W*D*H) | 95*92*50 mm / 3.74*3.62*1.97 in |
| Net Weight | 506g / 1.12lb |
| Package Weight (with 32V5A power supply) | 1100g / 2.43lb |
| Package Weight (with 48V5A power supply) | 1200g / 2.65lb |
8.1 Power Output Table
| Power Supply | Speaker Impedance | Rated Output Power |
|---|---|---|
| 32V/5A | 4Ω | 78W+78W |
| 6Ω | 71W+71W | |
| 8Ω | 65W+65W | |
| 36V/6A | 4Ω | 107W+107W |
| 6Ω | 100W+100W | |
| 8Ω | 94W+94W | |
| 48V/5A | 4Ω | 120W+120W |
| 6Ω | 110W+110W | |
| 8Ω | 102W+102W | |
| 48V/10A | 4Ω | 250W+250W |
| 6Ω | 210W+210W | |
| 8Ω | 185W+185W |
9. User Tips
- Op-Amp Experimentation: The A5 comes with NE5532 op-amps. For a different sound signature, consider "rolling" (replacing) them with compatible dual op-amps like 2134, 2604, 2068, or Muse02. This is an easy way to fine-tune the audio to your preference.
- Bluetooth Connectivity: The A5 does not have built-in Bluetooth. If wireless streaming is desired, connect an external Bluetooth audio receiver to the RCA input jacks.
10. Warranty and Support
The Nobsound A5 amplifier typically comes with a 2-year warranty. For technical support, warranty claims, or further assistance, please contact your retailer or the manufacturer directly. Keep your purchase receipt as proof of purchase.
