Douk Audio M4 Bluetooth 5.0 Four-Channel Amplifier 50W x 4 Review

The Douk Audio M4 is a four-channel digital amplifier priced at $79.99, designed for stereo or four-channel use at home and on the desktop. The feature that sets it apart is its flexible channel routing rather than raw audiophile specs.

The amp gives you four groups of speaker sockets, each with independent volume control, with a maximum output of 50W x 4 into 4Ω loads powered by the included 24V/4.5A supply. Speaker impedance can be 4-8Ω. One group of stereo RCA inputs, labelled CH3 and CH4, can be switched between input and output duty: as outputs, the four speaker sockets can drive two pairs of speakers or feed another M4 amplifier, so multiple amplifiers and speakers can be daisy-chained and one audio signal shared across several rooms. As inputs, one input corresponds to one output, meaning two groups of stereo audio (or four mono) can be fed in simultaneously.

Sources cover wired stereo RCA, Bluetooth 5.0 with a high-gain antenna, and U-disk playback supporting MP3, WMA, APE, FLAC and WAV up to 32GB. The maker notes the U-disk input takes priority over Bluetooth, so the drive should be removed to use the wireless input. Measured specs are THD of 0.05% at 1kHz and 1W, SNR of at least 98dB, an input sensitivity of 0.775V and a 20Hz-20KHz (±3dB) frequency response. The case is CNC-machined, anodized aluminium measuring 128 x 134 x 33mm and weighing 533g, and the small-signal and large-signal circuits are laid out separately for protection.

Douk Audio ships worldwide with free and expedited options, and the cost varies by country. Orders under 2kg ship by airmail (10-25 days) and orders over 2kg by DHL, UPS or FedEx (5-8 days); the 533g amplifier travels by airmail. Customers are responsible for any import duties or customs charges. All items come with a 30-day free return or full refund and a 1-year warranty, excluding orders placed by mistake, man-made damage or misuse, a subjective change of mind, and anything else outside the warranty terms.