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

Four Tubes and a Reference DAC, One Small Box

Pro-Ject's RS2 line packs reference engineering into compact chassis, and the Pre Box RS2 Digital is its centerpiece: a balanced preamplifier, dual-mono DAC, and headphone amplifier barely eight inches wide. Its party trick is the output stage: press a button and switch between a solid-state path and a tube path running four current-production 6922EH valves. Transistors for Tuesday, tubes for Sunday, one box for both.

Conversion runs through two ESS ES9038Q2M chips in dual-mono configuration, playing PCM up to 32-bit/768kHz and DSD512 over USB, with full hardware MQA unfolding. Digital inputs go far beyond USB: two optical, one coaxial, a balanced AES/EBU input, Bluetooth with aptX, and an I²S connection built for Pro-Ject's matching CD Box RS2 T transport. Balanced XLR and RCA analog inputs welcome your existing sources.

Outputs mirror the quality: balanced XLR and RCA pre-outs feed your power amplifier or powered speakers, and a 6.35mm headphone jack delivers 245mW into 32 ohms.

Small Chassis, Serious Intentions

The RS2 series is Pro-Ject's proof that size and seriousness are separate questions. The Pre Box RS2 Digital weighs under four pounds and shares shelf space gracefully, yet it's fully balanced, dual-mono, and controlled by a premium aluminum remote. The front display keeps volume and source visible, and silver or black aluminum finishes match the rest of the RS2 family.

The 6922EH tubes are current-production Electro-Harmonix valves, plentiful and affordable, so the tube path is a long-term companion rather than a worry.

What Reviewers Are Saying

Gordon Brockhouse of SoundStage! Simplifi, in a February 15, 2020 review, wrote plainly: "I loved this component," praising how it delivered "gobs of power but never sounded hard or glary" through headphones. His one gripe was some audible noise from the volume knob while adjusting it on his early sample.

Who Is This Preamp/DAC Best For?

• You can't choose between tubes and transistors — the switchable output stage means you don't have to.
• You want a reference DAC in tight spaces — dual-mono ES9038Q2M conversion in an eight-inch chassis.
• You own the CD Box RS2 T, or want it — the I²S input is purpose-built for the pairing.
• You listen on headphones — a capable amp drives most headphones from the front panel.
• If you need a phono input, the Pre Box RS2 Digital is line and digital only — Parasound's Halo P6 builds one in.

How Does It Connect to Your System?

Connect the balanced XLR or RCA outputs to your power amplifier or powered speakers. Your computer joins by USB, disc transports by I²S, coaxial, or optical, and broadcast-grade sources by AES/EBU. Analog components use the XLR or RCA inputs, and your phone pairs over Bluetooth. Then pick your flavor, tube or solid-state, from the listening chair.

Small footprint, full-size command.

Pairs Well With

Building around the Pre Box RS2 Digital? Here are some great companions:

• CD Transport: The I²S input awaits Pro-Ject's CD Box RS2 T — see our CD Players & Transports.
• Headphones: The front-panel amp deserves a good pair — see our Headphones.
• Cables: Quality XLR interconnects feed your power amp — see our Interconnect Cables.
• Audio Rack: A tidy home for a compact stack — see our Audio Racks.

Frequently Asked Questions

What does the tube/solid-state switch do?

It selects between two complete output stages: a solid-state path and a tube path with four 6922EH valves, so you can match the sound to the music.

What DAC is inside?

Two ESS ES9038Q2M chips in dual-mono configuration, playing PCM to 32-bit/768kHz and DSD512, with full hardware MQA unfolding.

What is the I²S input for?

It's a direct digital connection designed for Pro-Ject's CD Box RS2 T transport, keeping the signal in its purest form.

Does it have analog inputs?

Yes, one balanced XLR pair and one RCA pair, so it works as a complete system preamp.

Does it have Bluetooth?

Yes, Bluetooth with SBC, AAC, and aptX codecs.

What finishes are available?

Silver or black aluminum, matching the rest of Pro-Ject's RS2 series.

See It in Action

Steve Guttenberg reviews the Pre Box RS2 Digital with its CD Box RS2 T partner:

hxos plus unboxes the Pre Box RS2 Digital up close:

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