Nobsound AV-525 HiFi Bluetooth 5.0 Vacuum Tube Amplifier with Coaxial, Optical and USB Inputs Review

The Nobsound AV-525 is an integrated home audio amplifier priced at $459.99. It is a hybrid design that combines a vacuum tube preamp stage with a transistor power stage in a single vintage-styled chassis measuring 330 x 315 x 160mm and weighing 7.16kg.

On the amplifier side, Nobsound uses EL84/6K4/5726 tubes for pre-amplification and a WY2P tube for rectification, then hands power duties to 4x Toshiba 5200 and 4x 1943 transistors fed by dual toroidal transformers. Rated output is 100W + 100W into 4 ohm and 70W + 70W into 8 ohm, with speaker impedance of 4-16 ohm. THD is listed at 0.1% at 1kHz and SNR at 88dB or better, supported by treble and bass controls with a +/-9dB range.

Connectivity is the other story: Bluetooth 5.0, a U-disk USB input (MP3/WAV/APE/FLAC/WMA up to 16-bit/48kHz and 128GB), coaxial and optical digital inputs, and two groups of stereo RCA. Outputs include banana speaker jacks and a dedicated low-frequency output for an active subwoofer, making 2.1 channel builds straightforward. The package includes the amplifier, a power cord and a remote control (batteries not included).

Douk Audio ships worldwide with free and expedited options; costs vary by country. Parcels under 2kg ship airmail (10-25 days), heavier orders by DHL, UPS or FedEx (5-8 days), and any import duties or customs fees are the customer'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.