If you’re dealing with a mix of vinyl, digital streaming, TV audio, and headphones in your setup, you probably know how messy things can get. That’s exactly the kind of situation the Pro-Ject Pre Box S3 is designed to handle. This small but mighty preamplifier from Austrian brand Pro-Ject Audio Systems pulls together a variety of devices into one tidy box, giving you an easier way to manage your audio without a clutter of components.

At its core, the Pre Box S3 is all about centralizing control. It works as a stereo preamplifier, a headphone amp, and a digital-to-analog converter (DAC), and it brings support for both old-school and new-school gear. That includes analog sources like turntables and CD players, digital sources like laptops and streamers, TVs through HDMI eARC, and even Bluetooth audio from your phone.

Instead of needing separate gear for each function, this box handles source switching and volume control in one spot. You just connect it to a set of active speakers or a power amplifier, and you’re good to go.

Pro-Ject says the Pre Box S3 has 13 inputs and outputs, and they weren’t kidding. Here’s what you can expect:

Inputs:

• 2 RCA analog inputs – good for CD players or other line-level gear
• 1 phono input – specifically for moving-magnet turntables (with 45dB gain)
• 2 optical digital inputs (Toslink)
• 1 coaxial digital input (S/PDIF)
• 1 USB-C input – works with PCs, laptops, and some phones, up to 24-bit/192kHz
• 1 HDMI eARC input – lets you pull audio from your TV straight into your stereo
• Bluetooth 5.0 – with aptX HD for better sound quality when streaming wirelessly

Outputs:

• 1 variable RCA output – for connecting to an external amplifier
• 1 fixed RCA output – handy for multi-room setups or recording gear
• 1 subwoofer output
• 1 6.3mm headphone jack – with a built-in headphone amp
• 12V trigger output – for syncing with other components
• RS232 port – for integration with smart home or custom control systems

Bottom line: if you’ve got it, this box probably connects to it.

The Pre Box S3 isn’t just about ports. Inside, it features a dual-mono layout, which helps keep the left and right audio channels isolated for better stereo performance. Volume is handled by a motorized analog potentiometer, rather than a digital chip, which some listeners prefer for smoother adjustments and more natural sound.

For digital audio, the unit uses a Cirrus Logic CS4344 DAC, supporting high-resolution audio up to 24-bit/192kHz. That means it can handle most hi-res files, whether you’re streaming from services like Qobuz and Tidal or playing your own digital library.

As for the headphone output, it delivers 2 × 70mW into 32 ohms, which is plenty for typical headphones and everyday listening. It may not be enough for demanding high-impedance models, but it should be fine for most use cases.

The Pre Box S3 sticks to the company’s S3-series compact form factor, which makes it easy to fit on a desk, shelf, or media console. Its aluminum chassis adds durability and helps block interference from nearby electronics.

It’s available in black or silver, and it ships with a remote control so you don’t have to get up every time you want to change the volume or switch sources. It also pairs visually with other Pro-Ject S-series gear like the Amp Box S3 or CD Box RS2 Tube, if you’re building a matching stack.

The way people listen to music and TV has changed. Today’s systems often include a mix of streaming, vinyl, TV audio, and wireless gear, and the Pre Box S3 is clearly built to accommodate that. Whether you’re adding it to a compact power amp setup or using it to modernize an older system, it’s designed to grow with your needs.

Features like HDMI eARC, USB-C, and Bluetooth aptX HD make it easier to integrate with newer gear, while still supporting turntables and analog inputs for those who prefer more traditional sources.

Plus, with RS232 and 12V trigger support, it can easily fit into more advanced setups like multi-room audio systems or smart home installations.

Technical Specifications:

• Chassis: Aluminum S3.
• Control and integration: Trigger 12V, RS232, standby <0.5W.
• DAC: Cirrus Logic CS4344, 24-bit/192kHz.
• Inputs: 2 x RCA line, 1 x phono MM, 2 x optical S/PDIF, 1 x coaxial S/PDIF, 1 x asynchronous USB-C, 1 x HDMI eARC, Bluetooth 5.0 (aptX/aptX HD).
• Outputs: 1 x variable RCA, 1 x fixed line-level output, 1 x 6.3mm headphone output, 1 x subwoofer RCA.
• Headphone amp: 2 x 70mW into 32Ω.
• Phono gain: 45dB.
• Remote control: Yes.
• Volume control: Motor-driven analog potentiometer.
• Dimensions: 206 x 55 x 153mm.

The Pro-Ject Pre Box S3 isn’t trying to replace full-sized, high-end gear. But it’s a smart option for anyone looking to simplify their setup without sacrificing flexibility. If your system includes a mix of analog and digital gear, and you’re short on space or just want fewer boxes to deal with, this little preamp might be the tool to tie everything together.

The Pre Box S3 is designed and manufactured in Europe and will be available from February in Europe and North America, with a retail price of $699 / £499 / €599.

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