Nobsound Q4 Mini Bluetooth 5.0 USB DAC, S/PDIF Digital-to-Analog Converter, 192kHz Review

The Nobsound Q4 is a compact Bluetooth receiver and digital-to-analog converter priced at $49.99 (a regular $73.99 listing), designed to slot into a home audio system between digital sources and an amplifier or powered speakers. The latest version was upgraded in November 2022 with revised components, wiring and circuitry for lower distortion and a higher signal-to-noise ratio of up to 113dB.

Inputs cover five paths: Bluetooth 5.0, PC-USB, U-disk, optical and coaxial S/PDIF. The Q4 transmits streamed signals bit-perfect at up to 24-bit / 192kHz with low jitter, PC-USB accepts up to 96kHz / 24-bit, and the optical and coaxial inputs go to 192kHz / 24-bit. The USB and U-disk inputs are plug-and-play with no driver or software, and the U-disk port plays lossless audio formats directly. Douk Audio says the PC-USB path also supports OTG-equipped phones, though Android needs an OTG cable and iOS a camera kit, both supplied by the user.

On the output side, stereo RCA jacks feed amplifiers or powered speakers, and an onboard headphone amp circuit drives most 16-300 ohm headphones from the 3.5mm jack. A high-end chip combination keeps distortion at 0.005%, and treble and bass knobs let the Q4 work as a tone-controlling preamp. An output protect circuit guards downstream equipment. In daily use, a coding input selection knob (quieter and longer-lived than a toggle switch, per Douk Audio), independent input indicators and a full-function remote make operation straightforward, all wrapped in a fully metal case with a mirror-finish design.

Two quirks to know: the U-disk input takes priority over Bluetooth, so remove any USB drive before streaming, and the Q4's Bluetooth can only be found and connected when the input is switched to Bluetooth mode. Where the Q4 leads its class, per Douk Audio's own comparison, is offering Bluetooth and U-disk inputs, a remote and independent input indicators that similar DACs often lack.

Douk Audio ships worldwide with free and expedited options, and the cost varies by destination country. Packages under 2kg go by airmail (10-25 days); heavier orders ship via DHL, UPS or FedEx (5-8 days). Import duties or customs charges are the buyer's responsibility. The store offers a 30-day free return or full refund and a 1-year warranty on all items, excluding orders placed by mistake, man-made damage or misuse, subjective change of mind, and anything outside the warranty terms.