Интегральные усилители — Pro-Ject Stereo Box DS3

The Stereo Box DS3 by the Austrian maker Pro-Ject is a reworked, compact integrated amplifier that combines a line preamplifier, a phono stage, a Bluetooth receiver and headphone drive in one full aluminium case. It belongs to the DS3 range, is built in a dual mono layout and is handmade in Europe. Black and silver versions exist, and magnetic wooden side panels are sold separately. Pro-Ject describes the case size as kept only as large as necessary to save raw materials.

Key specs that matter

Rated output is 80 W per channel into 8 ohms and 150 W per channel into 4 ohms at 1% THD. Distortion stays below 0.01% at 10 W, and S/N exceeds 98 dB, or 105 dB A-weighted, at 1 kHz. Frequency response between 20 Hz and 20 kHz holds within -0.1 dB and +0.3 dB, and channel separation is -73 dB at 10 kHz. Three RCA line inputs have 860 mV sensitivity and 50 kOhm input impedance. The phono input accepts MM cartridges with 40 dB gain and 47 kOhm loading, or MC cartridges with 60 dB gain and 100 ohm loading. The housing measures 206 x 71 x 194 mm, or 211 mm deep with connectors, and has a mass of 1,800 g, adapter not included.

Engineering and use context

Level is adjusted through a motor-driven analogue potentiometer, so the included infrared remote, powered by two AAA cells, turns a real control rather than a digital attenuator, and the same handset switches between inputs. Bluetooth 5.0 supports aptX, aptX HD and the A2DP profile, giving a wireless source alongside the wired inputs. The gold-plated headphone output delivers 2 x 450 mW into 32 ohms. On the rear there is a variable RCA output for a subwoofer or a second amplifier, a fixed RCA output that ignores the volume setting, and trigger input and output sockets for switching other components on and off together. Speaker terminals are gold-plated and take 4 mm bananas, spades or unterminated cable. The amplifier is fed by an outboard 36 V, 5.5 A DC supply that accepts 100 to 240 V at 50 or 60 Hz, and standby draw is under 0.5 W.

Pairing

The phono stage works with both MM and MC types, so a turntable can connect directly without a separate preamplifier. The variable output lets an active subwoofer follow the main volume, whereas the fixed socket suits a recorder or another system. With the power rating into low loads, loudspeakers with lower impedance are within the rated range.

Alternatives

Within the same Box Design range, Pro-Ject offers the Stereo Box S3 BT, a much smaller integrated amplifier rated at 21 W per channel into 8 ohms.