Nobsound B100 HIFI Bluetooth Tube Amplifier USB DAC COA/OPT Hybrid Audio Amp 25W - New (Open Box) With 5 kinds of analog and digital audio input (Bluetooth 5.0 / PC-USB / U-disk / Coaxial / Optical / 2 groups of RCA), compatible with almost all audio devices such as MP3, phone, tablet, computer, TV, CD players etc. U-disk input supports lossless formats such as APE, FLAC, WAV etc., easy to enjoy HiFi music. Multiple audio outputs for different devices: besides speaker output, add 3.5mm headphone jack out to improve sound quality for headphones, and a low frequency output is specially designed to connect active subwoofer to build 2.1 channel audio system and strengthen bass sound effects. Combined design of tubes and transistors: using 6P16A as preamplification, the sound is clear, warm, smooth and delicate with high fidelity. 2PCS Toshiba C5198 and 2PCS 1941 triode for power amplification, each channel can output 25W, easily to drive all home passive speakers. Vintage looking specially with VU meter: exquisite black panel matches with retro vacuum tubes and VU meter to dynamically to decorate home desktop space. With independent function buttons and input indicators on the top panel, easy to use, very suitable for home and desktop audio system use.