1. Introduction
Thank you for purchasing the Nobsound Douk Audio T14 Phono Preamp. This device is designed to convert phono signals from your turntable to a line-level signal, allowing connection to amplifiers, active speakers, or headphones. It features MM/MC compatibility, tone controls, and a dedicated headphone output for an enhanced listening experience.
Figure 1: Nobsound Douk Audio T14 Phono Preamp (Front View)
This image shows the compact black casing of the T14 Phono Preamp, highlighting its front panel with the headphone output, power indicator, bass and treble control knobs, and the master volume/power knob.
2. Safety Information
- Read all instructions carefully before operating the device.
- Do not expose this device to rain or moisture.
- Do not place objects filled with liquids, such as vases, on the device.
- Ensure proper ventilation; do not block any ventilation openings.
- Use only the specified power supply (DC 5V, ≥0.6A).
- Disconnect the power cable during lightning storms or when unused for long periods.
- Do not attempt to repair or modify the device yourself. Refer all servicing to qualified personnel.
3. Package Contents
Please check the package for the following items:
- 1 x T14-EQ Preamplifier
- 1 x USB Cable (Type-C)
Note: A DC 5V power supply (e.g., a USB wall adapter) is not included and must be prepared separately.
Figure 2: Package Contents and Dimensions
This image illustrates the T14-EQ Preamplifier and the included USB Type-C cable, along with the dimensions of the unit and its net/package weights.
4. Product Overview
Familiarize yourself with the controls and connections of your T14-EQ Preamplifier.
Figure 3: Front and Rear Panel Layout
This diagram clearly labels all inputs, outputs, and controls on both the front and rear panels of the T14-EQ, including the 3.5mm headphone output, power indicator, bass/treble/volume knobs, RCA line out, DC 5V input, and MM/MC phono input.
Front Panel:
- 3.5mm Headphone Output: Connect your headphones (16-200Ω impedance). This output has priority over the RCA Line Out.
- Power Indicator: Illuminates when the unit is powered on.
- Bass Knob: Adjusts the low-frequency response (-5dB to +5dB).
- Treble Knob: Adjusts the high-frequency response (-5dB to +5dB).
- Volume / Power Knob: Turns the unit on/off and controls the output volume.
Rear Panel:
- RCA Line Out: Connect to an amplifier, active speakers, or other audio equipment.
- DC 5V IN (Type-C): Power input for the device.
- MM / MC Phono Input: Connect your turntable's RCA output.
5. Setup
5.1. MM/MC Switch Configuration
The T14-EQ supports both Moving Magnet (MM) and Moving Coil (MC) cartridges. You must select the correct setting using the DIP switch located on the bottom of the unit to match your turntable's cartridge type.
Figure 4: MM/MC DIP Switch on Bottom Panel
This image shows the underside of the T14-EQ unit, highlighting the red DIP switch. The switch allows users to select between MM (Moving Magnet) and MC (Moving Coil) phono input modes, crucial for proper turntable compatibility.
- MM (Moving Magnet): For standard MM cartridges. Set the DIP switches to the "MM" position as indicated on the unit.
- MC (Moving Coil): For low-output MC cartridges. Set the DIP switches to the "MC" position as indicated on the unit.
Important: Ensure the unit is powered off before changing the MM/MC switch setting.
5.2. Connecting Your Turntable
- Connect the RCA output cables from your turntable to the PHONO IN (RCA L/R) jacks on the rear panel of the T14-EQ.
- If your turntable has a ground wire, connect it to the ground terminal next to the PHONO IN jacks.
5.3. Connecting to Output Devices
- For Amplifiers/Active Speakers: Connect RCA cables from the LINE OUT (RCA L/R) jacks on the rear panel of the T14-EQ to an available line-level input on your amplifier or active speakers.
- For Headphones: Plug your 3.5mm headphones into the 3.5mm Headphone Output jack on the front panel.
5.4. Power Connection
- Connect the supplied USB Type-C cable to the DC 5V IN port on the rear panel of the T14-EQ.
- Connect the other end of the USB cable to a DC 5V power source (e.g., a USB wall adapter, computer USB port, or power bank).
6. Operating Instructions
6.1. Powering On/Off and Volume Control
- Rotate the Volume / Power Knob clockwise to turn on the unit. The power indicator light will illuminate.
- Continue rotating clockwise to increase the volume. Rotate counter-clockwise to decrease the volume.
- Rotate the knob fully counter-clockwise until it clicks to turn off the unit.
6.2. Tone Control
The T14-EQ features independent Bass and Treble controls to customize your sound.
Figure 5: Bass and Treble Control Knobs
This image highlights the Bass and Treble control knobs on the front panel, showing their adjustable range from -5dB to +5dB, allowing for personalized sound adjustments.
- Bass Knob: Rotate clockwise to boost bass frequencies, counter-clockwise to cut bass frequencies. (Range: ±5 dB)
- Treble Knob: Rotate clockwise to boost treble frequencies, counter-clockwise to cut treble frequencies. (Range: ±5 dB)
6.3. Headphone Output Priority
The 3.5mm headphone output has priority. When headphones are plugged in, the RCA Line Out will be muted.
Figure 6: Headphone Output in Use
This image demonstrates the T14-EQ connected to a turntable and headphones, illustrating the use of the 3.5mm headphone output for private listening.
Important: If you wish to use the stereo RCA output, ensure the headphone cable is unplugged from the 3.5mm jack.
7. Specifications
| Parameter | Value |
|---|---|
| Audio Input | MM/MC Phono |
| Audio Output | Stereo RCA / 3.5mm Headphone Jack |
| Input Level (MM) | 0.005V RMS |
| Input Level (MC) | 0.0005V RMS |
| Frequency Response | Complies with RIAA characteristics (±0.5 dB) |
| Treble/Bass Range | ±5 dB |
| Headphone Output Power (32Ω) | 250mW |
| Headphone Output Power (64Ω) | 100mW |
| Headphone Output Power (128Ω) | 60mW |
| Headphone Impedance Range | 16-200Ω |
| Harmonic Distortion Factor | ≤0.1% |
| Output Level | 0.6V RMS |
| Signal-to-Noise Ratio (Phono) | ≥80 dB |
| Operating Voltage | DC 5 V (≥0.6 A) |
| Dimensions (W x D x H) | 84 x 84 x 28 mm / 3.31 x 3.31 x 1.10 inches |
| Net Weight | 176 g / 0.39 lb |
| Package Weight | 400 g / 0.88 lb |
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound from RCA Line Out. | Headphones are plugged in. | Unplug headphones from the 3.5mm jack. |
| No sound or very low sound. | Incorrect MM/MC switch setting. Volume knob is too low. Power not connected or faulty. Incorrect input selected on amplifier/speakers. | Verify MM/MC switch matches your cartridge type. Increase the Volume knob. Ensure DC 5V power is connected and functional. Select the correct input on your connected audio device. |
| Humming or buzzing noise. | Ground wire not connected. Interference from other electronics. | Connect the turntable's ground wire to the preamp's ground terminal. Move the preamp away from other electronic devices or power cables. |
| Distorted sound. | Volume too high. Incorrect MM/MC setting. | Reduce the volume. Verify MM/MC switch matches your cartridge type. |
9. Maintenance
- Clean the unit with a soft, dry cloth. Do not use liquid cleaners or aerosols.
- Keep the unit away from excessive heat, humidity, and direct sunlight.
- Ensure proper ventilation around the unit.
10. Warranty and Support
Nobsound products are designed for reliability and performance. For warranty information and technical support, please refer to the documentation provided with your purchase or visit the official Nobsound website. Please retain your proof of purchase for warranty claims.
For further assistance, you may contact your retailer or the manufacturer directly.
