Douk Audio T6PRO HIFI TPA3255 Tube Amplifier User Manual

1. Introduction

The Douk Audio T6PRO is a compact tube amplifier that combines a sophisticated design with exceptional audio performance. It integrates JAN5725 vacuum tubes with a TPA3255 amplifier chip, delivering up to 300W per channel. This allows it to efficiently drive 4-8Ω speakers, providing impressive sound quality. The T6PRO offers versatile connectivity with Bluetooth, two stereo RCA inputs, and a 3.5mm AUX input. It also includes a preamp output for building multi-channel audio systems. Advanced tone controls, including treble, bass, and a super bass adjustment down to 20Hz, allow for precise sound customization. A prominent VU meter with dual panels and real-time pointer swings enhances the user experience with both auditory and visual feedback.

2. Key Features

• Dual VU Meter in One Visual Dashboard: Features dual VU meters on a single large board, with dynamic pointer swings that respond to audio signal changes. Automatic gain control (AGC) ensures smooth meter movement, providing real-time feedback with refined aesthetics.
• Hybrid Design with Strong Output: The T6PRO combines JAN5725 tubes working at 100V for warm, true tube sound and a TPA3255 digital amp chip delivering up to 300W per channel, easily driving 4-8Ω speakers. Its compact size makes it ideal for desktop setups, bookshelves, and home theaters.
• Versatile Inputs & Preamp Out: Supports Bluetooth 5.1, AUX, and dual RCA inputs for seamless connection and switching. A Bluetooth reset button enables fast re-pairing. The preamp output can connect to another amplifier or active speakers/subwoofer for 2.1 or multi-channel home theater systems.
• Super Bass & Audiophile Components: With treble, bass, and a super bass knob adjustable down to 20Hz, the T6PRO offers powerful bass effects. Audiophile-grade components like the QCC5125 Bluetooth chip and WIMA, ELNA, and Rubycon capacitors ensure exceptional clarity and low distortion.
• Refined Craftsmanship & Attractive Design: CNC-machined, custom all-aluminum alloy body with larger speaker binding posts for safe high-power handling. Retro-style VU meters and modern design combine to deliver a luxurious feel and immersive HIFI audio experience.

3. Packing List

Please check the contents of your package upon receipt. The standard package includes:

• 1 × T6PRO Amplifier
• 2 × JAN5725 Tube
• 1 × Bluetooth Antenna
• 1 × User Manual

Note: A DC 32V/5A or DC 48V/5A power adapter may be included depending on the purchased variant. If your package does not include a power adapter, you will need to provide one separately (DC 24-48V).

4. Setup Instructions

1. Install JAN5725 Tubes: Carefully insert the two JAN5725 vacuum tubes into their respective sockets on the top of the amplifier. Ensure they are seated firmly but do not force them.
2. Install Bluetooth Antenna: Screw the provided Bluetooth antenna into the designated connector on the rear panel of the amplifier.
3. Connect Speakers: Connect your passive speakers to the "SPEAKER OUTPUT" banana jacks on the rear panel. Ensure correct polarity (+ to + and - to -) for each channel. The T6PRO supports 4-8Ω speakers.
4. Connect Audio Sources:
   • Bluetooth: Power on the amplifier and select Bluetooth input. Pair your device (phone, tablet, etc.) with the T6PRO.
   • RCA Inputs: Connect your audio source (CD/DVD player, media player, etc.) to either "CH1" or "CH2" RCA inputs using appropriate RCA cables.
   • 3.5mm AUX Input: Connect your audio source (phone, laptop, MP3 player) to the "AUX" 3.5mm input.
5. Connect Pre-Out (Optional): If you wish to connect an active subwoofer or another amplifier, use an RCA cable to connect the "PRE OUT" port on the T6PRO to the input of your external device.
6. Connect Power: Connect the DC power adapter (24-48V) to the "DC 24V-48V" input on the rear panel. Then, plug the power adapter into a suitable wall outlet.

5. Operating Instructions

1. Power On/Off: Turn the "Power switch / input select knob" clockwise from the "OFF" position to power on the amplifier. Turn it counter-clockwise to "OFF" to power off.
2. Select Input: Rotate the "Power switch / input select knob" to choose your desired audio source: BT (Bluetooth), CH1 (RCA 1), CH2 (RCA 2), or AUX (3.5mm).
3. Adjust Volume: Use the large "Volume knob" to control the overall output volume.
4. Tone Control:
   • Treble Knob: Adjusts high frequencies (±8dB / 10KHz).
   • Bass Knob: Adjusts low frequencies (±6dB / 200Hz).
   • Super Bass Knob: Provides additional low-frequency enhancement, adjustable down to 20Hz (±10dB / 20Hz).
5. Bluetooth Pairing: When in Bluetooth input mode, the amplifier will be discoverable. If you need to re-pair or connect to a new device, press the "Bluetooth reset button" (RF) on the rear panel to clear previous connections.
6. VU Meter: The integrated VU meters will display the audio signal level in real-time, providing a visual representation of your music.

6. Maintenance

• Cleaning: Use a soft, dry cloth to clean the amplifier's exterior. Avoid using harsh chemicals or abrasive cleaners.
• Tube Replacement: The JAN5725 tubes are pluggable and can be replaced. Compatible tube types include 6J1, 6J2, 6J3, 6J4, 6J5, 6K4, 6*IN, 6*4N, 6*5N, 5654, 6AK5, EF95, 6BA6, 403B, etc. Ensure the amplifier is powered off and unplugged before replacing tubes.
• Ventilation: Ensure adequate ventilation around the amplifier to prevent overheating. Do not block ventilation openings.

7. Troubleshooting

• No Sound Output:
  • Check all cable connections (audio sources, speakers, power).
  • Ensure the correct input source is selected.
  • Verify that the volume knob is not at minimum.
  • Confirm tubes are properly seated.
• Distorted Sound:
  • Reduce the volume from both the source and the amplifier.
  • Check speaker impedance compatibility (4-8Ω).
  • Ensure audio cables are not damaged or loose.
• Bluetooth Connection Issues:
  • Ensure the amplifier is in Bluetooth input mode.
  • Press the Bluetooth reset button (RF) on the rear panel to clear previous pairings and try connecting again.
  • Move your Bluetooth device closer to the amplifier.
• VU Meter Not Moving:
  • Ensure there is an active audio signal playing.
  • Check if the input sensitivity is too low.

8. Specifications

Power Output Table of T6PRO

9. User Tips

• Power Adapter Choice: While a 32V/5A or 48V/5A adapter is optional, you may replace it with a higher-power adapter (e.g., 48V/10A) for potentially better performance and higher output, especially with demanding speakers. Ensure the voltage remains within the DC 24-48V range.
• Tube Rolling: The JAN5725 tubes are designed for easy replacement, allowing users to experiment with different compatible tubes (e.g., 6J1, 6J2, 6J3, 6J4, 6J5, 6K4, 6*IN, 6*4N, 6*5N, 5654, 6AK5, EF95, 6BA6, 403B) to fine-tune the sound to their preference.
• Pre-Out Functionality: The volume, treble, bass, and super bass controls for the pre-out port are synchronized with the speaker output, offering consistent sound adjustments across your entire audio setup.
• Voltage Compatibility: The amplifier operates on DC 24-48V. When using in different regions, ensure your power adapter is compatible with your local mains voltage and provides the correct DC output within this range.

10. Warranty and Support

For warranty information, technical support, or service inquiries, please refer to the documentation provided with your purchase or contact Douk Audio customer service directly. Keep your proof of purchase for warranty claims.