Pro-Ject Head Box S2 Headphone Amplifier - Black

A Serious Headphone Amp That Fits in Your Hand

Your headphones are only as good as what's driving them. The Pro-Ject Head Box S2 is a dedicated headphone amplifier about the size of a paperback book, built to replace the weak headphone outputs found on computers, TVs, and budget receivers with clean, capable amplification.

Despite its size, the numbers are real: 725mW into 32 ohms, distortion of just 0.002%, and an output impedance under 1 ohm, which keeps the sound consistent across different headphones. Frequency response stretches from 20Hz to 80kHz. Both a 6.35mm and a 3.5mm headphone jack sit on the front, and they work at the same time, so two people can listen at once.

The casing is an aluminum and metal sandwich that shields the circuit from interference and vibration, a build touch usually reserved for pricier gear. It comes in silver or black, matching the rest of Pro-Ject's Box Design lineup.

What Reviewers Are Saying

John Grandberg of Darko.Audio, in an August 11, 2020 review, praised its "respectable clarity," "well-defined layering between various instruments," and "nearly pitch-black background" with in-ear monitors, concluding it "impresses for its size and price" and makes "a great starting point for anyone looking for a first dedicated headphone amplifier."

Who Is This Amplifier Best For?

• You're buying your first dedicated headphone amp — this is one of the most affordable ways to hear what your headphones can really do.
• You have a small desk or crowded rack — at about 4" wide, it fits almost anywhere.
• Two people share one system — both headphone jacks work simultaneously.
• If your headphones are very hard to drive or you want balanced connections, a more powerful amp is the better tool — the Head Box S2 is built for everyday headphones, not exotic loads.

How Does It Connect to Your System?

Connect any line-level source, such as a DAC, streamer, or preamp output, to the RCA inputs. A handy RCA loop output passes the signal through to your main amplifier, so you can add the Head Box S2 to an existing system without giving up an input. Power comes from a small 5V supply (included), and standby draw is under 0.1 watts.

Pairs Well With

Building your system? Here are some great companions for the Head Box S2:

• Headphones: Pair it with a quality dynamic headphone — see our Headphones.
• DAC: Feed it a clean source signal — see our Digital-to-Analog Converters.
• Cables: A good RCA cable completes the chain — see our Interconnect Cables.

Frequently Asked Questions

How powerful is it?

It delivers 725mW into 32 ohms, plenty for most dynamic headphones and in-ear monitors.

Can two people listen at once?

Yes. The 6.35mm and 3.5mm jacks work at the same time.

Can I add it to my existing system without losing an input?

Yes. The RCA loop output passes the signal through to your amplifier or receiver.

What finishes are available?

Silver or black, matching Pro-Ject's other Box Design components.

See It in Action

Pro-Ject USA introduces the Head Box S2:

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• 40+ Years of Expertise — Since 1981, we've helped over a million music lovers find the right gear.
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Learn More

Want to learn more about headphone amplifiers, DACs, or desktop audio? Visit our Learning Center for guides, tips, and expert advice.