Pro-Ject Phono Box DS3 B

The Phono Box DS3 B sits within Pro-Ject’s DS3 series of compact hi-fi separates, bringing balanced connectivity and fully discrete circuitry previously reserved for the flagship RS range to a more accessible price point. It replaces the earlier Phono Box DS2 as Pro-Ject’s mid-range phono preamplifier, positioned above the entry-level Phono Box S3 B and below the reference-grade Phono Box RS2.

Fully Discrete Circuit Topology

The DS3 B employs a fully discrete, symmetrical gain stage built from individual electronic components rather than integrated operational amplifiers. This dual-mono design separates left and right channels entirely, each with its own gain path. The RIAA equalisation stage is split passive and discrete — again avoiding op-amps — and achieves an accuracy of less than 0.25 dB across the full 20 Hz–20 kHz bandwidth. The result is a signal-to-noise ratio of 111 dBV (A-weighted) in MM mode and 91 dBV (A-weighted) in MC mode, with total harmonic distortion below 0.001% at 1 kHz for moving magnet cartridges.

True Balanced Connection

Phono cartridges are inherently balanced signal transducers, and the DS3 B is designed to exploit this. Three input options are provided: a 5-pin mini XLR for turntables with balanced tonearm wiring, a pair of full-size XLR connectors, and a standard RCA pair for single-ended connections. Outputs mirror this flexibility with both XLR and RCA pairs, with the balanced XLR outputs providing a +6 dB gain advantage. The heavy aluminium and steel chassis construction provides effective shielding against electromagnetic interference.

Stepless Impedance Matching

The front panel features a continuously variable impedance dial that sweeps from 10 to 1,000 ohms, enabling real-time adjustment during playback to find the precise loading for any MC cartridge. A fixed 47 kΩ setting is available for MM cartridges. Input capacitance is selectable at 50, 150, 300, or 400 pF, and gain can be set independently at 40, 45, 50, 55, 60, or 65 dB. A subsonic filter with a 20 Hz cutoff and 18 dB/octave slope is also available.

Dual Turntable Support

The DS3 B can connect two turntables simultaneously — one via the balanced inputs and one via RCA. Each input stores its own impedance, capacitance, and gain settings in memory, so switching between turntables recalls the correct configuration automatically. A 12 V trigger input and output allows integration with automated power-on sequences in a multi-component system.

Construction

The chassis comprises a steel enclosure wrapped in brushed aluminium panels, providing both rigidity and electrical isolation. Optional magnetic wooden side panels are available separately for a warmer aesthetic. Designed and handcrafted in Europe.