Pro-Ject Phono Box S2 Ultra Phono Preamplifier

Fully Discrete Circuit · Op-Amp Free Design · Polystyrene Capacitors · Entry-Level High-End Flagship

The Pro-Ject Phono Box S2 Ultra is an advanced flagship version in the S2 series, featuring a fully discrete circuit design that completely avoids op-amps. It uses audiophile-grade polystyrene capacitors and a split RIAA equalization, delivering cleaner, more delicate, and dynamically superior sound. It supports both MM and MC cartridges and offers extensive load and gain adjustments, making it almost perfectly compatible with most cartridges on the market.

Compact and refined with a mature sound, it's a highly capable phono stage choice for entry-level high-end systems.

Product Basic Information

• Type: Fully Discrete MM / MC Phono Preamplifier
• Supported Cartridges: MM (Moving Magnet) and MC (Moving Coil)
• Adjustment Method: Bottom DIP switches (Gain, Impedance, Capacitance)
• Output: RCA Line-Level Output
• Color: Black or Silver
• Origin: Hand-made in Europe
• Accessories: External 18V DC Power Supply

Core Technology Highlights

• Fully Discrete Circuit Design: No op-amps used, resulting in a more natural and harmonious sound
• Audiophile-Grade Polystyrene Capacitors: Considered the "holy grail" component in phono stages, significantly improving transparency and detail
• Split RIAA Equalization: More accurate reproduction of the RIAA curve
• Adjustable Gain: 40 / 43 / 60 / 63 dB, flexibly matching different output cartridges
• Adjustable Input Impedance and Capacitance: 10Ω / 100Ω / 1kΩ / 47kΩ; 100 / 220 pF
• Switchable Subsonic Filter: -18dB @ 20Hz, more powerfully suppressing vibrations and warped record noise
• Metal Casing: Effectively shields electromagnetic interference and vibrations
• External Power Supply: Reduces internal interference, extremely low standby power consumption

Detailed Specifications

• Input Impedance: 10Ω / 100Ω / 1kΩ / 47kΩ
• Input Capacitance: 100 / 220 pF
• Gain: 40 / 43 / 60 / 63 dB
• Signal-to-Noise Ratio: MM approx. 89 dB
• Total Harmonic Distortion: Extremely low (approx. 0.00052%)
• RIAA Accuracy: 20Hz–20kHz / max. 0.4dB
• Subsonic Filter: -18dB @ 20Hz
• Inputs / Outputs: 1 set of RCA each
• Power Supply: External 18V / 500mA DC
• Power Consumption: Approx. 80mA
• Dimensions: 103 × 37 × 119 mm
• Weight: Approx. 570g

Sound Performance and Capabilities

The Phono Box S2 Ultra delivers an extremely clean, delicate, and layered sound. It offers a blacker background, richer details, superior dynamics, and a more expansive soundstage. The mid-range is natural and full-bodied, the bass is powerful and controlled, and the treble is clear without being harsh, presenting an overall mature, transparent, and musical performance.

Compared to the standard S2, the Ultra version significantly surpasses it in resolution, airiness, and spaciousness, fully unleashing the potential of high-end cartridges.

Online Reviews

• HIFI.DE: "Truly defines the upper limit of sound quality achievable within a classic phono stage form factor... delicate, richly structured, and dynamically excellent."
• Hi-Fi News / Users and Media: Excellent detail and dynamics, highly musical, outstanding value for money, a "treasure" for entry-level high-end.
• Multiple reviewers affirm its "significant improvement brought by the fully discrete design," with sound that is airier and more precise than the standard S2, highly recommended.