Nobsound HiFi Stereo Bluetooth 5.0 Digital Power Amplifier USB Music Player 2/4 Channel Home Multi Zone Audio Amp Receiver 50W*4

        Features One group of stereo RCA (CH3 and CH4) can be used as audio input or output by switching the selector, to acheive different demands: CH3/CH4 as audio output: 4 groups of speaker sockets can connect to 2 pair of speakers. Besides connect to active speakers, CH3/CH4 also can connect to another M4 amplifier to connect more speakers, in this way multiple amplifiers and multiple speakers can be connected in turn, to achieve one audio signal be shared in several rooms.   CH3/CH4 as audio input: one input corresponds to one output (ex. CH1 speaker socket will output the audio signal that CH1 inputs), which means that two groups of stereo audio signal (or 4 groups of mono audio signal) can be input at the same time. Supporting wired 2 groups of stereo RCA and wireless Bluetooth 5.0 input, compatible with most common audio device such as phones, computers, TVs, MP3, TV, CD players etc. With U-disk input, it can be used as a digital music player, supporting MP3, WAV, APE, FLAC and WMA lossless formats. With 4 groups of speaker sockets output, they can output at the same time and each channel with independent volume control. Its max output power can reach 50W×4, and equipped with high-quality 24V/4.5A power supply, enough to drive most home speakers. Reasonable circuit layout, concise wiring and high-quality components to ensure HiFi clear sound and long time stable work. Separate design of small and large signal circuit for better circuit protection. Unique Bluetooth design without any external antenna, very practical and beautiful. Propersize with exquisite appearance, aluminum alloy case is CNC machined and with anodizing process, more fashionable and durable, very suitable for home, office and desktop audio system use. Notice: U-disk input is prior to Bluetooth input, so please make sure U-disk has been pulled out if you want Bluetooth input. Parameters Model: Douk Audio M4 Channel: 2.0 / 4.0 Audio input: Bluetooth/Stereo RCA/U-disk Audio output: speaker sockets U-disk support format: MP3, WMA, APE, FLAC, WAV... U-disk capacity: max 32G Bluetooth version: 5.0 Speaker impedance: 4-8Ω Max output power: 50W*4 (4Ω load) SNR: ≥98dB Input sensitivity: 0.775V THD: 0.05%(1kHz 1W) Frequency Response: 20Hz-20KHz(±3dB) Working voltage: DC 12-24V Color: Black Dimensions(W*D*H): 128*134*33mm / 5.04*5.28*1.30in Net weight: 540g / 1.19lb Package weight: 1100g / 2.43lb Packing List 1*M4 Amplifier 1*24V/4.5A Power Supply 1 Set*Raw Cable Speaker Jacks 1*Manual