Douk Audio U10 HiFi Valve Tube Preamp Stereo AUX Desktop Audio Preamp 6.35mm/3.5mm Headphone Amplifier

Warm tips:
Not inlcude power adapter, recommend to use original high-quality power adapter (DC5V/≥2A ). U10 won't work normally if the current below 2A.
Features
U10 headphone amplifier with strong power:  stereo 3.5mm AUX and RCA inputs, compatible with most audio source such as MP3, phones, computers, CD players etc.. Dual headphone jacks (3.5/6.35mm) output up to 1100mW, easily to drive all 18-600Ω headphones; U10 also can be used as a preamp to improve the sound quality for amplifiers or active speakers.
Advanced design and HIFI sound: innovative built-in voltage boost circuit, U10 always works at a high voltage of 24V even only powered by DC 5V, the sound with deadly quiet background, amazing purity and transparency, accurate position and wide sound field, easy use and unrivalled sound are both achieved at the same time.
Pluggable design with higher playability: 2PCS 6A2 tubes are adopted to soften and warm the audio, sounds real and natural, full and mellow, delicate and sweet. Both tubes and op amps are designed with pluggable socket, convenient for tube rolling, op amp upgrading and sound-shaping, different styles of sound can be enjoyed easily.
Excellent manufacturing and most cost-effective: all metal case with good shielding, pure ceramic tube socket with antioxidant contact etc., U10 provides excellent sound and strong power for your headphones in such a mini size, specially suitable for the audiophiles who love listening to vocals, string music, light or classic music etc..
Warm tips:
1. Inputs (3.5mm / RCA) and outputs (6.35mm/3.5mm jack) are connected in parallel, in other words, all inputs and outputs work simultaneously. Don't connect 3.5mm and RCA inputs at the same time, or else audio signals will be mixed.
2. Pluggable tube socket design, 6A2 can be replaced by the following models:
6J1,6ж1П,6AK5,6BC5,403A/B,5654,EF40,EF95,CV850,6J2,6ж2П,6AS6,CV2522,EF11/732,CV4011,6J3,6ж3П,EF96,CV848,6BC6,6AG5, 6J4,6ж4,6136,6BX6,6AC7,EF94,6AU6,6K4,6K5,6K4П,6BA6,6DA6,EF89/93,5749
3. U10 can easily drive all headphones even with high-impedance such as HD580/HD600/HD650 / K701/K702/Q701 / DT880/T70/T90 / SR225/SR325/RS1e etc.
Parameters:
Brand: Douk Audio
Model: U10
Audio input: 3.5mm AUX / Stereo RCA
Audio output: 3.5mm / 6.35mm headphone jack
Tube Model: 6A2 (2PCS)
Op amp model: NE5532 (2PCS)
Frequency response: 20Hz-30KHz
Output power: ≥1100mW (32Ω)
Matched headphone impedance: 18-600Ω
Signal to noise ratio: ≥110DB
Input voltage: DC 5V (≥2A)
Working voltage inside: DC 24V
Net weight: 200g / 0.44lb
Package weight: 300g / 0.66lb
Dimensions (W*D*H): 69*95*30mm / 2.72*3.74*1.18in (not including tubes)
Package Dimensions (W*D*H): 132*85*90mm / 5.20*3.35*3.54in
Packing List
1 × U10 Headphone Amplifier
2 × 6A2 Tube
1 × Acrylic Board
1 × DC 5V Power Adapter
1 × User Manual