Nobsound NS-08E Vacuum Tube Headphone Amplifier and Preamplifier User Manual

1. Introduction

The Nobsound NS-08E is a versatile Hi-Fi tube headphone amplifier designed to enhance your audio experience. It can deliver over 1100mW at 32Ω, making it suitable for driving headphones and headsets with impedances ranging from 18 to 600 ohms. This unit also functions as a stereo preamplifier for other amplifiers and active speakers. The new version features 6J3 vacuum tubes, offering a warm tube sound and the flexibility of replaceable tubes for sound customization. Its circuit design aims for low background noise, powerful bass, and brilliant treble.

Figure 1: Nobsound NS-08E Vacuum Tube Headphone Amplifier

2. Setup Instructions

Follow these steps to set up your Nobsound NS-08E amplifier:

1. Unpack the Amplifier: Carefully remove all components from the packaging.
2. Tube Installation: The amplifier comes with 6J3 vacuum tubes. Carefully insert them into their sockets. The amplifier supports direct replacement with various tube models, including 6J1, 6Ж1П, 6AK5, 6BC5, 403A/B, 5654, EF40, EF95, CV850, 6J2, 6Ж2П, 6AS6, CV2522, EF11/732, CV4011, 6J3, 6Ж3П, EF96, CV848, 6BC6, 6AG5, 6J4, 6J36, 6BX6, 6AC7, EF94, 6AU6, 6J5, 6Ж5П, EF80, CV2521, EF36, 6AH6, 6AN5, 6K4, 6K5, 6K4П, 6BA6, 6DA6, EF89/93, 5749. The video below demonstrates the tube replacement process.
3. Power Connection: Connect the provided power supply to the DC 6V input on the rear of the amplifier. Plug the power supply into an AC 100-240V 50/60 Hz outlet.
4. Audio Source Connection: Connect your audio source (e.g., phone, tablet, CD player, laptop, computer) to the 3.5mm AUX IN jack on the front panel.
5. Headphone/Output Connection: Connect your headphones or other audio output devices (e.g., amplifier, active speakers) to the 3.5mm AUX OUT jack on the front panel.
6. Warm-up Period: Allow the amplifier to warm up for approximately 15 seconds after powering on before connecting your audio source and headset for optimal performance.
7. Headphone Compatibility: This amplifier is designed for headphones with an impedance of 24-600Ω. Armature earphones and headphones with very low resistance and high sensitivity may not be suitable.
8. Optional Preamplifier Use: For enhanced preamplifier functionality, consider using the NS-10P (ASIN: B07719G56B) as a dedicated stereo preamplifier for other amplifiers and active speakers.

Figure 2: Front Panel Connections and Compatible Devices

3. Operating Instructions

Once the amplifier is set up, follow these guidelines for operation:

• Power On/Off: Use the red power button located on the rear panel to turn the amplifier on or off.
• Volume Control: Adjust the volume using the gold knob on the front panel. Rotate clockwise to increase volume and counter-clockwise to decrease.
• Tube Rolling: The NS-08E features a replaceable tube design, allowing you to experiment with different compatible vacuum tubes (as listed in the Setup Instructions section) to customize the sound profile.
• Placement: Keep the amplifier steady during use to prevent microphonic effects from the tubes. Ensure it is positioned away from devices that may cause interference, such as routers or mobile phones.

Figure 3: Amplifier in Use with Smartphone and Headphones

4. Maintenance

Proper maintenance ensures the longevity and optimal performance of your amplifier:

• Cleaning: Use a soft, dry cloth to clean the exterior of the amplifier. Avoid using liquid cleaners or abrasive materials.
• Tube Replacement: Over time, vacuum tubes may degrade. Replace them with compatible tubes as needed to maintain sound quality. Refer to the list of replaceable tubes in the Setup Instructions section.
• Heat Management: The amplifier's CNC aluminum shell is designed for heat dissipation. It is normal for the unit to become warm during extended use. For prolonged operation, avoid direct skin contact with the amplifier's surface, especially the tubes, as they can become very hot. Ensure adequate ventilation around the amplifier.
• Storage: When not in use for extended periods, disconnect the power supply and store the amplifier in a cool, dry place.

5. Troubleshooting

If you encounter issues with your Nobsound NS-08E, refer to the following common problems and solutions:

• No Sound:
  • Ensure the power supply is securely connected and the amplifier is powered on.
  • Verify that the audio source is playing and connected correctly to the 3.5mm AUX IN.
  • Check headphone connections to the 3.5mm AUX OUT.
  • Increase the volume using the front panel knob.
• Static or Buzzing Noise:
  • Ensure the amplifier is kept away from potential interference sources like routers, mobile phones, or other electronic devices.
  • If noise persists, disconnect all audio inputs and check if the noise is still present. This can help determine if the noise originates from the amplifier or the audio source.
  • Ensure tubes are properly seated.
• Distorted Sound:
  • Reduce the volume level.
  • Check if your headphones' impedance is within the recommended 18-600 ohm range.
  • Consider replacing the vacuum tubes if they are old or damaged.
• Intermittent Sound or Channel Imbalance:
  • Check all cable connections for looseness or damage.
  • Ensure the vacuum tubes are fully and correctly inserted into their sockets.

6. Specifications

Figure 4: Product Dimensions and Weight

7. Warranty and Support

Nobsound is committed to providing quality products and customer satisfaction.

• Customer Service: For any questions, concerns, or support needs regarding your NS-08E amplifier, please contact Nobsound customer service through Amazon.
• Product Information: For additional product information and other Nobsound offerings, visit the official Nobsound Store on Amazon: Nobsound Store.