Pro-Ject Pre Box S2 Digital DAC/Preamplifier

Small Is Beautiful

Equipment report
Solid-state preamplifiers,
Digital-to-analog converters
Pro-Ject Pre Box S2
Pro-Ject Pre Box S2 Digital DAC/Preamplifier

The primary fault I hear with budget-priced audio components is their lack of inner detail, dynamic life, and overall musical definition. I’ve often heard these sonic under-performers described as sounding “gray.” That’s not an issue with the Pre Box S2. When I placed the Pre Box S2 in my nearfield system, it replaced the $999 Mytek Liberty DAC/pre. Even upon initial listen, without any run-in time, it was obvious that the Pre Box S2’s performance was not a big step downward, but more like sideways.

Time for the audiophile equivalent of a warning label: If you are an especially tweaky, compulsive audiophile, do not begin to explore the sonic differences between the various PCM filter options on the Pre Box S2, for that way leads to madness. Well, maybe not total madness, but certainly the sort of wrinkled-brow consternation brought on by too many subtly variable choices. The Pre Box S2 filter options include optimal transient (Pro-Ject preferred), fast roll-off (linear phase), slow roll-off (linear phase), minimum phase fast, minimum phase slow, linear apodizing, hybrid filter, and a brickwall filter.

It would be so easy if only one PCM filter sonically “ruled them all,” but I did not find that to be the case. I found myself vacillating between the optimal transient, linear apodizing, and hybrid filters as my “most often settled upon” after multiple blind A/B listening sessions. Given the physical location of the Pre Box S2 in my nearfield setup, my filter choices were true blind tests (I could not see the front panel while listening, so I didn’t know which filter I preferred until my choice was made). Never, in all my tests, did I choose the brickwall filter. Also, with some cuts I could not reliably pick a favorite. That’s where the consternation part set in.

So, how does the Pro-Ject Pre Box S2 sound? Well, let’s assume you have chosen the optimal filter for a particular track. At that point you would be hearing a clean, well-defined, neutral/natural harmonic presentation that tries to be as “not there” as it can. Depending on your transducer choice, a system based around the Pre Box S2 could be tilted in virtually any sonic direction you choose. Pick a component with a noticeable sonic “personality”—be it your headphones, loudspeaker, or power amplifier—and the sonic palette will be dictated far more by that link of the chain than by the Pre Box S2. And as if that weren’t enough sonic flavoring options, the EQ functions available on all the top playback apps now allow precise sonic tailoring, so end users can tweak the sound of a Pre Box S2-based system to a fare-the-well. The answer to the question “What kind of sound has the Pre Box S2 got?” is “What kind of sound do you want?”

Since $399 isn’t a huge sum when it comes to high-performance DACs, you would think the Pre Box S2 would have little in the way of serious competition. You would be wrong. The $399 IFI xDSD delivers a similarly high level of sonic performance and offers several features the Pre Box S2 lacks. Depending on your primary usage-location and -situation, one will be more useful to you than the other. If you will mainly be using a DAC connected to a computer in a desktop system, the Pre Box would be my first choice due to its superior ergonomics, including the dedicated RCA outputs and separate headphone output, easier-to-read display, MQA decoding, and greater expansion options. But if I required a DAC that would primarily serve as my portable device’s DAC, spending more time in transit, located in a pocket rather than on a desktop, I would choose the xDSD since it has a built-in long-life battery, supports Bluetooth devices, and can easily be operated “blind” while in your pocket. You can’t go wrong with either one, as both offer excellent sound and features at entry-level prices, but each has particular situations where it will excel.

For audiophiles with a slightly larger budget looking for a complete, one-box home-based electronics system solution, I would recommend the $599 PS Audio Sprout100 over the Pre Box S2 Digital because you will be hard-pressed to find an amplifier for $200 to add to the Pre Box S2 that provides the same amount of power and sonic quality as the Sprout100. The Sprout is not expandable like the Pro-Ject S2 system, but it delivers great sound and elegant ergonomics within its compact package.

The Pro-Ject Pre Box S2 Digital offers audiophiles a very high-value DAC/digital preamp at an almost ridiculously low price. Not only does it include a plethora of important features, but it sounds good, has an elegantly designed control surface, and is expandable. As an audiophile’s needs grow, Pro-Ject micro-systems have the components to support nearly every potential source and format available through various accessory units designed to perform specific functions. Got vinyl? Need a device to convert your turntable’s raw output into a digital stream? Pro-Ject has a box for that, too, and at a similarly low cost.

The Pro-Ject Pre Box S2 isn’t just for audiophile newcomers. Perhaps you’ve been involved in high-performance audio for a while and already have a great-sounding DAC, but it lacks USB and MQA capabilities. Just add the Pro-Ject Pre Box S2 Digital to your system, connect it to a computer (or smartphone) via USB, and you can enjoy all the wonders of modern computer-based audio without a major monetary commitment. If you like what you hear, you can “upgrade” later, perhaps adding the Stream Box S2 Ultra to liberate the Pre Box S2 from being tethered to your computer.

Perhaps the best way to view the Pro-Ject Pre Box S2 (and most of the components in the Pro-Ject S2 line) is to consider it a sonic building block or Lego. You can acquire Pro-Ject components to do exactly what you need, no more and no less. The Pre Box S2 Digital can be the beginning piece in a system that can grow and change as you do. While not quite bespoke audio, the Pro-Ject Pre Box S2 is one small part of an elegant system that gives even audiophiles with limited means a way to assemble a first-class audio system tailored specifically to their requirements. If you are looking for a first step to begin your computer audiophile journey or a small addition to your more traditional audio mega-system, I recommend the Pro-Ject Pre Box S2. Small, in the case of the Pro-Ject Pre Box S2 is, indeed, beautiful.

Specs & Pricing

Type: DAC/pre/headphone amplifier
Inputs: USB, TosLink, coaxial SPDIF
Formats supported: PCM, 32/44.1/48/88.2/96/176.2/192/352.8/384/768 kHz; DSD, DSD64, DSD128, DSD256, and DSD512
Output: One ¼" stereo headphone, one pair variable RCA
Dimensions: 4" x 1.4" x 4"
Weight: 1.1 lbs.
Price: $399

Sumiko (U.S. Distributor)
2431 Fifth Street
Berkeley, CA 94710
(510) 843-4500

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