Features: Unique and amazing combination: integrated T9 amplifier with VU meter into whole in such a mini size, when enjoy HiFi music, the pointer dancing in the warm light with strong vintage feelings, dynamically decorates the audio system space. HiFi clear sound with tone control: resonable circuit and concise wiring, adopts vacuum tubes to soften the sound and filter out the digital feelings, sounds warm and sweet without noise. Also with treble and bass knobs to adjust one's own preferable sound styles, presents HiFi music with rousing highs and deep lows. Strong output power and low frequency output: use amp IC TPA3221, each channel can output 100W(4?), match perfectly and easily to drive all 3-8? passive speakers, adds a low frequency output easy to connect active speakers and build 2.1 channel system, the bass effects is greatly enhanced. With multiple digital audio inputs: Bluetooth 5.0 / USB / Coaxial / Optical / stereo RCA, compatible with most audio device such as phones, computers, tablets, TVs, TV, CD players etc. The perfect combination of DAC and amplifier, very suitale for audiophiles who have various audio devices. Practical funtions to simplify use: with input selection and indicators, clearly to show the working status in real time; aluminum alloy case is specially designed, cool and unique to decorate your desktop space. Product paramstes: Chipt: 6K4+TPA3221*2+AC6926C+SA9123+MS8412+NE5532 Tube model: 6K4x2Pcs Replaceable tubes: 6J1, 6J2, GE5654, 6J3, 6J4, 6J5, 6?1?, 6AK5, etc. Support: MP3/WMA/APE/FLAC/WAV pc-usb sampling rate: 24bit96khz Optical fiber/coaxial sampling rate: 24bit 192khz Bluetooth sampling rate: 24bit 48khz pc-usb support system: XP/W7/W8/W10/MAC/Linux Total harmonic distortion: 0.07% Signal to noise ratio: ?98db Frequency response: 20-20Khz (1db) Treble/bass adjustment range: 6db Speaker impedance: 3-8? Output power: 100W*2 4? load Input mode: Bluetooth / RCA/pc-usb/optical/coaxial Support equipment: mobile phones, tablets, computers, MP3, TV, etc. Output mode: passive speaker, active subwoofer Working power supply: DC18-30V Size: 115*98*54mm Package included: 1Pcs Tube T9 tube amplifier + 1Pcs Power adapter(optinal)