Douk Audio U4 Mini Bluetooth 5.0 Tube Headphone Amplifier USB DAC Stereo Audio Preamp APTX-LL

• Douk Audio U4 is a multi-function HiFi audio device, with Bluetooth 5.0 and USB input, stereo RCA, 3.5mm AUX, 3.5mm headphone jack output, which can be used as a Bluetooth receiver, a USB DAC, a headphone amp and a stereo preamp, compatible with phone, computer, power amplifier, active speakers and so on.

• Adopting classic 6N3 vacuum tube(much better than 6J*) to effectively eliminate the harsh digital sound, providing HiFi clear, soft and smooth, warm and sweet tube sound. The sound field is wide, especially suitable for vocals, strings, light music, classical music, etc.

• High-end components and unique design:

Bluetooth 5.0 (QCC3008 chip) supports APT-X, APTX-LL, adding classic TDA1543 chip for decoding and external high-gain detachable antenna, makes its sound transmission low-delay and lossless.
USB sound card part uses CM6642 chip, supports 24bit 192KHz transmission, compatible with Windows / Mac / Linux system and Android mobile phone with OTG function, no need for driver, plug and play.
Headphone amp uses classic MAX9722 decoding chip, 300mW output power can drive most 16-600 ohm headphones.

• Super mini size and exquisite appearance, with power and select switch, working indicators and volume control. Using all-aluminum chassis CNC machined and laser carving, looks fashionable and powerful, perfectly suitable for your desktop or a smaller space in your home or office

• Audio input: Bluetooth 5.0 / USB
• Audio output: stereo RCA / 3.5mm AUX / 3.5mm headphone jack
• Bluetooth chip: QCC3008
• Decoding chip: TDA1543
• USB chip: CM6642
• Headphone amp chip: MAX9722
• Signal to noise ratio: >99 dB
• Dynamic range: >99 dB
• Amp rated power output: 300MW
• Amp impedance 16-600 ohms
• Distortion: THD+N: 0.004% (RL > 10 kΩ) /  0.020% (RL = 32 Ω)
• colour: black
• Dimensions(L*W*H): 97*77*32mm / 3.82*3.03*1.26in
• Net weight: 250g / 0.55lb
• Package weight: 470g / 1.04lb

• 1*U4 Headphone Amp
• 1*6N3 tube
• 1*12V Power Adapter
• 1*USB Cable
• 1*Bluetooth Antenna
• 1*Manual