1. Introduction
Thank you for choosing the Nobsound T7 7-Band Equalizer Balanced XLR / RCA Preamp. This device is designed to enhance your audio experience by providing precise control over your sound's frequency response. It features independent 7-band EQ adjustment, balanced XLR and RCA inputs/outputs, and a bypass mode for original sound playback. Please read this manual thoroughly before operating the device to ensure proper setup and optimal performance.
Figure 1: Nobsound T7 Stereo Equalizer with key features.
2. Safety Information
- Do not expose this device to rain or moisture.
- Do not disassemble the unit. Refer all servicing to qualified personnel.
- Ensure proper ventilation around the unit.
- Use only the provided DC 12V power adapter.
- Keep the unit away from heat sources and direct sunlight.
3. Package Contents
Please check the package for the following items:
- 1 x T7 Preamp
- 1 x DC 12V Power Adapter
Figure 2: Package contents and dimensions of the T7 Preamp.
4. Product Overview
4.1 Front Panel
Figure 3: Front panel controls of the Nobsound T7.
- Input Selector / Power Switch: Selects between RCA input, Balanced (BAL) input, or powers off the unit.
- 64Hz Adjustment Knob: Adjusts the gain for the 64Hz frequency band.
- 125Hz Adjustment Knob: Adjusts the gain for the 125Hz frequency band.
- 250Hz Adjustment Knob: Adjusts the gain for the 250Hz frequency band.
- 500Hz Adjustment Knob: Adjusts the gain for the 500Hz frequency band.
- 2KHz Adjustment Knob: Adjusts the gain for the 2KHz frequency band.
- 4KHz Adjustment Knob: Adjusts the gain for the 4KHz frequency band.
- 8KHz Adjustment Knob: Adjusts the gain for the 8KHz frequency band.
4.2 Rear Panel
Figure 4: Rear panel connections of the Nobsound T7.
- Balanced XLR Input (L/R): For connecting audio sources with XLR outputs.
- RCA Input (L/R): For connecting audio sources with RCA outputs.
- Balanced XLR Output (L/R): For connecting to amplifiers or active speakers with XLR inputs.
- RCA Output (L/R): For connecting to amplifiers or active speakers with RCA inputs.
- DC 12V IN: Power input for the provided DC 12V adapter.
5. Setup
Follow these steps to connect your Nobsound T7 Equalizer:
- Power Connection: Connect the provided DC 12V power adapter to the 'DC 12V IN' port on the rear panel of the T7, then plug the adapter into a power outlet.
- Audio Input Connection:
- For RCA Input: Connect your audio source (e.g., CD player, phone, computer) to the 'RCA Input' jacks on the rear panel using RCA cables.
- For Balanced XLR Input: Connect your audio source to the 'Balanced XLR Input' jacks on the rear panel using XLR cables.
- Audio Output Connection:
- For RCA Output: Connect the 'RCA Output' jacks on the rear panel of the T7 to your amplifier or active speakers using RCA cables.
- For Balanced XLR Output: Connect the 'Balanced XLR Output' jacks on the rear panel of the T7 to your amplifier or active speakers using XLR cables.
- Input Selection: On the front panel, turn the input selector knob to 'RCA' or 'BAL' corresponding to your input connection.
Note: The T7 does not have a volume control knob. It will output at its rated level. Ensure your amplifier or active speakers have their own volume control.
Note: Both XLR and RCA outputs will function simultaneously.
6. Operating Instructions
6.1 Power On/Off
To power on the unit, turn the input selector knob from 'OFF' to either 'RCA' or 'BAL'. To power off, turn the knob to 'OFF'.
6.2 Equalizer Adjustment
The T7 features seven independent frequency band controls, ranging from 64Hz to 8KHz. Each knob allows for a gain adjustment from -6dB to +6dB. Rotate the knobs clockwise to boost a frequency band and counter-clockwise to cut it. Experiment with these controls to tailor the sound to your preference or to compensate for room acoustics and speaker characteristics.
Figure 5: Adjusting the 7-band EQ equalizer.
6.3 Bypass Mode
When the unit is powered off (input selector knob set to 'OFF'), the T7 automatically enters bypass mode. In this mode, the audio signal passes directly through the unit without any equalization or preamplification, allowing you to enjoy the original, unaltered sound from your source.
Figure 6: Bypass mode for original sound.
7. Specifications
| Parameter | Value |
|---|---|
| Model | Douk Audio T7 |
| Audio Input | Single-ended RCA / Balanced XLR |
| Audio Output | Single-ended RCA / Balanced XLR |
| Frequency Response | 20Hz～20KHz (±1dB) |
| Frequency Bands | 64Hz / 125Hz / 250Hz / 500Hz / 2KHz / 4KHz / 8KHz |
| RCA Input Sensitivity | 0.775Vrms |
| RCA Output Level | 1.2Vrms |
| BAL Input Sensitivity | 1.5Vrms |
| BAL Output Level | 3Vrms |
| THD (Total Harmonic Distortion) | 0.003% |
| SNR (Signal-to-Noise Ratio) | ≥104dB |
| Working Voltage | DC12V (≥1.5A) |
| Dimensions (W*D*H) | 152*126*42mm / 5.98*4.96*1.65in |
| Net Weight | 700g / 1.54lb |
| Package Weight | 1.0kg / 2.20lb |
8. Troubleshooting
8.1 No Sound Output
- Ensure the T7 is powered on and the input selector is set to the correct input (RCA or BAL).
- Verify all audio cables are securely connected to both the T7 and your audio source/amplifier/active speakers.
- Check the volume level on your amplifier or active speakers, as the T7 does not have its own volume control.
- Test with different audio cables and sources to rule out faulty components.
8.2 Distorted Sound
- Ensure all connections are secure and free from interference.
- Check if the input signal level from your source is too high, causing clipping.
- Adjust the EQ knobs to ensure no single frequency band is excessively boosted, which could lead to distortion.
- Test with different audio sources and cables.
8.3 Equalizer Not Working
- Ensure the unit is powered on and not in bypass mode (input selector not on 'OFF').
- Verify that the EQ knobs are adjusted away from their center (0dB) position.
9. User Tips
- Volume Control: Remember that the T7 does not have a volume control. Always manage your system's overall volume using your amplifier or active speakers.
- Simultaneous Outputs: Both XLR and RCA outputs are active at the same time. This can be useful for connecting to multiple systems or for monitoring.
- Subtle Adjustments: When adjusting the equalizer, start with small changes. Even minor tweaks can significantly impact the sound.
- Room Acoustics: Use the equalizer to compensate for deficiencies in your listening room's acoustics, such as excessive bass or harsh treble.
- Speaker Correction: The EQ can help fine-tune the frequency response of your speakers to better match your preferences.
10. Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Do not use liquid cleaners or solvents.
- Storage: When not in use for extended periods, store the unit in a cool, dry place, away from direct sunlight and extreme temperatures.
- Ventilation: Ensure the unit has adequate ventilation and that its vents are not blocked.
11. Warranty and Support
Nobsound products are designed for reliability and performance. For warranty information or technical support, please refer to the documentation provided at the time of purchase or contact your retailer. Keep your purchase receipt as proof of purchase.
