Pro-Ject Pre Box RS2 Digital - Balanced Preamplifier with DAC- Silver

What You Need to Know

Tube or Solid State—At the Flip of a Switch

The Pre Box RS2 Digital is Pro-Ject's flagship DAC, preamplifier, and headphone amp in one compact aluminum chassis—and its party trick is unique at this price: a fully balanced, discrete output stage switchable between four 6922EH tubes and solid state. Want maximum detail and clarity? Run solid state. Craving vintage sweetness and roundness? Flip to tube. As reviewer Steve Guttenberg put it: "You can run this fully-balanced solid-state or fully-balanced tube—that is pretty special."

Dual Mono ESS Sabre DACs

Unlike most DACs in its class, the RS2 uses two ESS9038Q2M Sabre converters in a true dual-mono configuration with separate signal paths for left and right channels. It handles up to 32-bit/768kHz PCM and native DSD512—every digital file you can buy or stream—with a powerful multi-core XMOS processor and CPLD re-clocking keeping timing pristine. Eight selectable digital filters let you fine-tune the presentation to taste, and full hardware MQA unfolding is on board.

A Complete Control Center

Nine digital inputs—USB, I2S (with master clock output for Pro-Ject's CD Box RS2 T transport), dual optical, coaxial, balanced AES/EBU, and Bluetooth with aptX—join balanced XLR and RCA analog inputs. Balanced XLR and RCA pre-outs feed your amp directly, and the no-compromise headphone stage is fully DC-coupled with no coupling capacitors anywhere, driving everything from 8 to 300 ohms. A crisp front display, responsive menu, and full-aluminum remote complete the package. Available in silver or black.

Features & Specifications

Switchable Output Stage — Fully balanced, discrete circuitry: 6922EH tube or solid state, your choice.

Dual Mono ESS9038Q2M DACs — Separate converters and signal paths per channel; 32/768 PCM, DSD512, hardware MQA.

Nine Digital Inputs — USB, I2S, 2x optical, coaxial, AES/EBU, and Bluetooth aptX.

True Balanced Preamp — XLR and RCA analog inputs and pre-outs for direct-to-amp use.

DC-Coupled Headphone Amp — No coupling capacitors anywhere; power for virtually any headphone.

Eight Digital Filters — Including the proprietary MQA optimal transient filter; tune the sound to your taste.

Specifications

• Type: DAC / Preamplifier / Headphone Amplifier
• DAC: 2 x ESS9038Q2M (Dual Mono) — 32-bit/768kHz PCM, DSD512
• Digital Inputs: USB 2.0, I2S (for CD Box RS2 T), 2 x Optical (24/192), Coaxial (24/192), AES/EBU (24/192), Bluetooth v4.0 (SBC, AAC, aptX)
• Analog Inputs: XLR (pair), RCA (pair)
• Analog Outputs: Pre-Out XLR & RCA; 6.35mm Headphone Jack
• Output Stage: Discrete, Balanced — Switchable Tube (4 x 6922EH) / Solid State
• Headphone Output Power: 245mW/32 Ohm; 150mW/8 Ohm; 90mW/300 Ohm
• THD+N: <0.006% Solid State / 0.017% Tube (2V RMS, 1kHz)
• MQA: Full Hardware Unfolding; Master Clock Output: 16.9344MHz
• Power Supply: 20V/3A DC (included); Standby Consumption <0.5W
• Dimensions: 8.1"W x 2.8"H x 8.7"D (with sockets)
• Weight: 3.8 lbs (without power supply)
• Finish: Silver or Black Aluminum; Full-Aluminum Remote Included
• Sold By: Each

Frequently Asked Questions

Tube or solid state—which should I use?

Both, whenever you like—that's the point. Solid state delivers maximum detail, clarity, and the lowest distortion; the tube stage adds warmth and roundness that flatters bright recordings and long listening sessions. Switching takes seconds, so match the mode to the music.

Can it replace my preamp entirely?

Yes. With balanced and single-ended analog inputs, nine digital inputs, precise volume control, and XLR/RCA pre-outs, the RS2 connects directly to a power amp or active speakers as a complete control center.

What is the I2S input for?

It's a dedicated differential connection for Pro-Ject's CD Box RS2 T transport—the EISA Award-winning combination. The RS2 even supplies the master clock to the transport, keeping both units in perfect sync for the cleanest possible CD playback.

Will it work with my streamer and headphones?

Yes—it's Roon Tested, works with Audirvana, and pairs naturally with streamers like Pro-Ject's Stream Box S2 Ultra via USB. The DC-coupled headphone amp comfortably drives planars, high-impedance dynamics, and sensitive in-ears alike.

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