Pro-Ject Stream Box S2 Ultra Music Streamer - Black

The Tiny Box That Teaches Your DAC to Stream

You already own a DAC you love. What it can't do is stream. The Pro-Ject Stream Box S2 Ultra fixes that in a chassis barely bigger than your hand: a Roon Ready network bridge that pulls music from your network and streaming services, then hands a clean, bit-perfect digital signal to any USB DAC. No computer required, no compromise invited.

The services roster runs deep for a box this small. Tidal, Spotify, Qobuz, and HRA Streaming are built in, with TuneIn internet radio alongside. AirPlay arrives via Shairport, and DLNA handles your network library. The Stream Box is fully Roon Ready and Audirvana certified.

Control it from the Pro-Ject Play app on iOS or Android, from a web browser, or from Roon itself. Playback passes PCM up to 32-bit and 352.8kHz, and DSD256, straight through to your converter.

Two USB ports take hard drives full of music. Attach an external USB CD drive as well, and the Stream Box will even rip your discs onto one of those drives for you.

The USB Detox Trick

Pro-Ject built in something clever: a "detox" input. Connect your computer to the micro USB port, and the Stream Box re-clocks and cleans its noisy USB signal before passing it to your DAC through the audio-optimized output. Your laptop's electrical grime stays out of your music.

The engineering follows Pro-Ject's Box Design philosophy: a compact aluminum case about four inches square, dedicated internal power supplies, and Ethernet, Wi-Fi, and Bluetooth connectivity. An HDMI output can even put the interface on a monitor or TV. It comes in black or silver.

What Reviewers Are Saying

John Atkinson of Stereophile, in a May 17, 2019 review, praised the Stream Box S2 Ultra as an "affordable server and network bridge," the "lower-cost turnkey solution" he had been searching for, noting "the benefit of two sets of power-filtration circuits" feeding compatible components.

Gordon Brockhouse of SoundStage! Simplifi, in a January 1, 2019 review, called it "a nifty little product with lots of applications" and "a solid component."

Who Is This Streamer Best For?

• You love your current DAC — the Stream Box adds streaming without replacing what already sounds right.
• You use Roon or Audirvana — it's certified for both, rare at this size and price.
• You stream from a computer today — the detox input cleans your PC's USB signal on its way to the DAC.
• You want small and quiet — four inches square tucks behind the DAC it serves.
• Your DAC is the one you want to keep — a digital-only streamer puts the whole budget into delivering a clean signal to it. See our digital-to-analog converters.

How Does It Connect to Your System?

Connect the audio-optimized USB output to your DAC, then join your network by Ethernet or Wi-Fi. Plug music-filled USB drives into the storage ports, or your computer into the detox input. Control playback from the Pro-Ject Play app, a browser, or Roon, and let your DAC do what it does best with a cleaner signal than your computer ever gave it.

From there, every streaming service and network file in the house flows through one tiny box.

Pairs Well With

Building your streaming system? Here are some great companions for the Stream Box S2 Ultra:

• DAC: The essential partner for its USB output — see our Digital-to-Analog Converters.
• Integrated Amplifier: Downstream of your DAC — see our Integrated Amplifiers.
• Cables: A quality USB cable feeds your converter — see our Interconnect Cables.
• Audio Rack: Keep the whole stack tidy — see our Audio Racks.

Frequently Asked Questions

Does it have a built-in DAC or analog outputs?

It's a pure digital source that feeds any USB DAC through its audio-optimized output.

What streaming services does it support?

Tidal, Spotify, Qobuz, HRA Streaming, and TuneIn internet radio, plus AirPlay and DLNA.

Is it Roon Ready?

Yes, fully certified, and Audirvana certified as well.

What is the USB detox input?

Connect your computer to it, and the Stream Box re-clocks and cleans the USB signal before it reaches your DAC.

What resolutions does it pass?

Bit-perfect PCM up to 32-bit/352.8kHz and DSD256, passed straight through to your converter.

Can it play my stored music?

Yes. Two USB ports accept external drives, and an external USB CD drive lets it rip discs too.

See It in Action

Pro-Ject's own Tech Talk digs into the Stream Box S2 Ultra's design:

Audio Advice tours the streaming toolbox inside:

Why Audio Advisor?

• 40+ Years of Expertise — Since 1981, we've helped over a million music lovers find the right gear.
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• Flexible Payment Options — Financing available so you can start listening now.

Learn More

Want to learn more about music streamers, DACs, or building a streaming system? Visit our Learning Center for guides, tips, and expert advice.