Pro-Ject Stereo Box S3 BT Integrated Amplifier with Bluetooth - Black

Big Sound Where There Is No Room

Sometimes there is no space for a full-size amplifier and you want proper sound anyway. The Pro-Ject Stereo Box S3 BT is built for exactly that: an integrated amplifier small enough for a desk, with enough power to drive a real pair of speakers.

It belongs to Pro-Ject's Box series, made in Europe and offered in black or silver. The point of the format is that it fits places a normal component cannot, without the sound being an afterthought of the size.

More Than One Way Out

A 3.5mm variable output sits alongside the speaker terminals. That can feed a second amplifier, a pair of active speakers or a subwoofer, which is unusual on something this small and makes it far more flexible than it looks.

Bluetooth Done at aptX HD

The Bluetooth input runs aptX HD, carrying up to 24-bit and 48kHz. That is better than CD quality over the air, and the codec also improves the signal-to-noise compared with a standard Bluetooth link.

And Two Wired Inputs

Two line-level RCA inputs sit on the back for the sources that stay put: a CD player, a phono stage, a streamer. Between those and Bluetooth, most desks are fully covered.

Controls are deliberately simple. A single press moves between the inputs and adjusts the volume, so there is no menu to learn and nothing at all to configure before the first record plays.

Who Is This Integrated Amplifier Best For?

• The room has no space for a real amplifier — this is a full integrated in a case that fits a desk or a shelf where nothing else would.
• You stream from a phone — aptX HD carries up to 24-bit and 48kHz, which is better than CD quality and quieter than a standard Bluetooth link.
• You may add a subwoofer later — the 3.5mm variable output feeds one, or a second amplifier, or a pair of active speakers.
• You want it simple — inputs and volume are handled by a button press, with no menu and nothing to set up first.
• Its inputs are two line-level RCA and Bluetooth — there is no optical or coaxial socket, so a television needs a converter first. Browse our DACs for that.

How Does It Connect to Your System?

Speakers go to the terminals. Two line-level RCA inputs take a CD player, a streamer or a phono stage, and Bluetooth with aptX HD covers a phone, tablet or laptop.

The 3.5mm variable output can drive a subwoofer, a second amplifier or a pair of active speakers, which is how a box this size ends up in bigger systems than you would expect.

Pairs Well With

Building your system? Here are some great companions:

• Speakers: A compact pair suits it best — see our Bookshelf Speakers.
• Subwoofer: The variable output will feed one — browse our Subwoofers.
• DAC: To bring a television or transport in — see our DACs.
• Cables: Speaker cable to finish the job — see our Speaker Cables.

Frequently Asked Questions

Which inputs does it have?

Two line-level RCA inputs and a Bluetooth input with aptX HD.

What quality does the Bluetooth carry?

Up to 24-bit and 48kHz over aptX HD, which is better than CD quality and quieter than standard Bluetooth.

What is the 3.5mm output for?

A subwoofer, a second amplifier or a pair of active speakers. It is variable, so it follows the volume control.

Can I connect a television?

The inputs are analog and Bluetooth only, so a television needs a converter to turn its optical output into line level first.

How do the controls work?

A button press moves between inputs and adjusts volume. There is no menu to learn.

What finishes are available?

Black or silver, and it is made in Europe.

See It in Action

AV Atmos looks at the Stereo Box S3 BT alongside its bigger brother:

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Learn More

Want to learn more about compact amplifiers, Bluetooth audio, or building a desktop system? Visit our Learning Center for guides, tips, and expert advice.