Pro-Ject Stereo Box DS3 black

Pro-Ject Stereo Box DS3: the compact integrated amplifier that has it all

Third generation of the Box Design DS series, the Stereo Box DS3 builds on the formula of its predecessor, the DS2, muscling it up where it counts: more power, an updated Bluetooth module, and a remote control now included in the box. The form factor remains ultra-compact (206 × 71 × 211 mm, 1.8 kg), but the feature set has grown more mature. Pro-Ject delivers here a stereo integrated amplifier that combines phono preamplification, amplification, and wireless connectivity in an aluminium enclosure barely larger than a thick paperback book.

An aluminium chassis built to last

The chassis is machined from a solid aluminium block, a choice that serves two purposes: shielding the electronics from electromagnetic interference and vibrations, and giving the unit a rigidity that plastic or stamped sheet metal simply cannot match. The result, in black or anodised silver, is understated and timeless. For those who prefer a warmer aesthetic, Pro-Ject offers wooden side panels (walnut, rosewood, or eucalyptus) that attach magnetically. Installation takes only a few seconds, and the finish pairs beautifully with the brand’s turntables.

On the front, an oversized volume knob dominates the centre of the panel. This analogue potentiometer is motorised: it follows commands from the included remote control, preserving the signal path without routing through a digital volume control. An input selector, a gain button (+6 dB), a Bluetooth pairing button, and a 6.35 mm headphone jack complete the front panel.

150 watts per channel in dual mono configuration

The amplification section has been redesigned compared to the DS2. Output power climbs to 2 × 150 W into 4 ohms (2 × 80 W into 8 ohms), all arranged in a dual mono configuration: each channel has its own amplification stage, improving stereo separation and reducing crosstalk. Manufacturer specifications list a separation of -73 dB at 10 kHz and total harmonic distortion below 0.01% at 10 W.

Frequency response is rated at -0.1 dB / +0.3 dB across the 20 Hz – 20 kHz band, and the signal-to-noise ratio reaches 98 dB (105 dB A-weighted). These figures, for a device of this size, are remarkable. In practice, the DS3 can drive low-sensitivity floorstanding speakers without any sign of strain — something its compact dimensions would never suggest.

An integrated phono stage, compatible with MM and MC

Where many compact integrated amplifiers make do with a line input, the Stereo Box DS3 includes a phono stage compatible with both moving magnet (MM) and moving coil (MC) cartridges. Gain is set at 40 dB for MM cartridges (input impedance 47 kΩ) and 60 dB for MC cartridges (input impedance 100 Ω). An MM/MC switch is accessible on the rear of the unit.

This integration eliminates the need for a separate phono preamplifier, a significant expense when building a system around a turntable. The quality of the phono stage is naturally constrained by the space and budget available in a device of this size: owners of high-end, very low-output MC cartridges may prefer a dedicated phono preamp, but for the vast majority of common MM and MC cartridges, the results are perfectly usable.

Five sources, one box

The rear panel houses five inputs in total. The phono input (a pair of RCA connectors + ground terminal) sits alongside three RCA line inputs, complemented by a Bluetooth 5.0 receiver with support for aptX and aptX HD codecs (A2DP profile). The Bluetooth stream can reach 24-bit / 48 kHz, placing the wireless streaming quality a step above standard SBC.

On the output side, the speaker terminals accept 4 mm banana plugs, spade connectors, or bare wire. Two pairs of RCA outputs round out the connectivity: a variable output (whose level tracks the volume potentiometer) for connecting a subwoofer or a secondary power amplifier, and a fixed output (constant level, independent of volume) for feeding a recorder or distributing the signal to another room. The RCA connectors are gold-plated.

The 12 V trigger inputs and outputs allow other Pro-Ject (or compatible) devices to power on or off simultaneously with the DS3 — a handy feature in a multi-component system.

A headphone output that pulls its weight

The front-panel headphone jack (6.35 mm) delivers 2 × 450 mW into 32 ohms. This is a high output level for an integrated amplifier of this size, sufficient to drive most low-sensitivity hi-fi headphones. Pro-Ject has given this output its own dedicated amplification stage, separate from the main circuit: the headphones are not simply tapped off the speaker output via a resistor, which translates to better control and lower background noise.

What has changed compared to the DS2

The Stereo Box DS3 looks very much like its predecessor, and that is intentional: Pro-Ject has kept the same chassis dimensions to ensure compatibility with the DS2 series wooden side panels. The improvements lie under the hood and in the box.

Output power has been significantly increased (150 W versus approximately 55 W into 4 ohms for the DS2, based on manufacturer data from that time). The Bluetooth module is upgraded to version 5.0 with aptX HD support, which was absent from the previous model. And the remote control, which was an optional accessory on the DS2, is now included as standard. The external power supply remains the same format (36 V / 5.5 A), compatible with 100 – 240 V mains.

Technical specifications

Audio performance

• Output power
  • 2 x 80 W into 8 ohms
  • 2 x 150 W into 4 ohms
• Frequency response: 20 Hz – 20 kHz (-0.1 dB / +0.3 dB)
• Signal-to-noise ratio: 98 dB (105 dB A-weighted)
• Total harmonic distortion (THD): < 0.01% at 10 W
• Channel separation: -73 dB at 10 kHz
• Dual mono design for improved channel separation

Phono section

• Compatibility: MM and MC cartridges
• Gain
  • MM: 40 dB
  • MC: 60 dB
• Impedance
  • MM: 47 kΩ
  • MC: 100 Ω

Bluetooth connectivity

• Version: Bluetooth 5.0
• Codecs: aptX, aptX HD
• Profile: A2DP
• High-quality streaming up to 24-bit / 48 kHz

Inputs

• 1 phono input (MM / MC)
• 3 RCA line inputs
• Bluetooth 5.0 (aptX, aptX HD, A2DP)

Outputs

• Speaker terminals compatible with banana plugs, spades, or bare wire
• 1 variable RCA output (subwoofer / secondary amplifier)
• 1 fixed RCA output (recording / distribution)
• High-power headphone output: 2 x 450 mW
• Trigger In / Out

Power supply and consumption

• Power supply: 36 V / 5.5 A
• Mains compatibility: 100 – 240 V
• Standby power consumption: < 0.5 W

Dimensions and weight

• Dimensions (W x H x D): 206 x 71 x 211 mm (223 mm with connectors)
• Weight: 1.8 kg (excluding power supply)

Design and manufacturing

• Machined aluminum chassis with anti-vibration and anti-interference design
• Available finishes: black, silver
• Designed and manufactured in Europe

Included accessories

• Remote control with motorized volume control

Recommended uses

• Complete Hi-Fi systems combining vinyl and digital
• Demanding floorstanding or bookshelf speakers
• High-quality Bluetooth streaming
• Audiophile headphone listening