Pro-Ject Phono Box DS3 B Phono Preamplifier

True Balanced Design · Fully Discrete Dual-Mono · Continuously Variable Loading · High-End Entry-Level Balanced Phono Preamp

The Pro-Ject Phono Box DS3 B is an advanced model in the DS series that supports True Balanced operation. Inheriting high-end technology from the RS series, it features a fully discrete (no op-amp), symmetrical dual-mono gain stage and passive RIAA equalization. It supports both MM and MC cartridges and includes continuously variable MC impedance adjustment (fine-tunable during playback), as well as full balanced inputs/outputs, delivering a quieter, more detailed, and more dynamic vinyl performance.

With its steel-aluminum composite chassis and comprehensive features, it is a cost-effective choice for upgrading to a balanced system.

Basic Product Information

• Type: Fully Balanced MM / MC Phono Preamplifier
• Supported Cartridges: MM (Moving Magnet) and MC (Moving Coil)
• Inputs: 5-pin mini XLR Balanced + XLR Balanced + RCA Unbalanced
• Outputs: XLR Balanced + RCA Unbalanced
• Adjustment Method: Front Panel Continuously Variable Impedance + Gain/Capacitance Switching
• Color: Black or Silver (Optional Magnetic Wood Side Panels Available)
• Origin: Hand-Made in Europe
• Accessories: External 18V DC Power Supply

Core Technology Highlights

• True Balanced Design: Complete balanced signal path, significantly reduces noise
• Fully Discrete Circuitry: No op-amps used, resulting in a more natural sound with better dynamics
• Symmetrical Dual-Mono Gain Stage: Excellent channel separation and low distortion
• Passive RIAA Equalization: Accurately reproduces record characteristics
• Continuously Variable MC Impedance: 10–1000Ω potentiometer adjustment, real-time fine-tuning during playback
• Multiple Gain Options: 40 / 45 / 50 / 55 / 60 / 65 dB (XLR output adds +6dB)
• Adjustable Capacitance: 50 / 150 / 300 / 400 pF
• Switchable Subsonic Filter: 20Hz / 18dB/octave
• Steel-Aluminum Composite Chassis: Effectively shields against vibration and electromagnetic interference
• Trigger Function: Convenient for linked on/off operation with other system components

Detailed Specifications

• Input Impedance: Continuously variable 10–1000Ω or fixed 47kΩ
• Input Capacitance: 50 / 150 / 300 / 400 pF
• Gain: 40 / 45 / 50 / 55 / 60 / 65 dB (XLR +6dB)
• Signal-to-Noise Ratio: MM 104dBV / 111dBV (A-weighted); MC 85dBV / 91dBV (A-weighted)
• Total Harmonic Distortion: At 1kHz, MM <0.001%, MC <0.004%; At 20Hz–20kHz, MM <0.005%, MC <0.01%
• RIAA Accuracy: 20Hz–20kHz / max. 0.25dB
• Subsonic Filter: 20Hz / 18dB/octave
• Inputs: 1 × 5-pin mini XLR + 1 × XLR + 1 × RCA
• Outputs: 1 × XLR + 1 × RCA
• Power Supply: External 18V / 500mA DC
• Power Consumption: Max approx. 290mA (Standby <0.5W)
• Dimensions: 206 × 72 × 194 mm (approx. 205mm including terminals)
• Weight: Approx. 1.48 kg

Sound Performance and Capabilities

The Phono Box DS3 B delivers a clean, transparent, and layered sound. The background is extremely dark, with rich details, an expansive soundstage, and excellent dynamics. The mid-range is natural and full-bodied, the bass is powerful with good control, and the treble is clear without being harsh. When using balanced connections, noise is further reduced, and resolution and spatial imaging are significantly improved, presenting a mature, precise, and convincing musical performance.

The continuously variable impedance allows it to precisely match different MC cartridges, fully unleashing the potential of high-end systems.

Online Reviews

• TechHive: "Brings high-end balanced technology to a wider audience... excellent listening experience when paired with a balanced turntable."
• Users and Media: Comprehensive features, clean and dynamic sound, practical continuously variable impedance, an excellent choice for entering high-end balanced systems.
• Multiple reviewers commend its "inheriting RS series technology but being more accessible," significant improvement with balanced connections, and high cost-effectiveness.