Pro-Ject PreBox S2 Digital
Micro-sized digital stereo preamp with built-in headphone amp (Silver)
Our take on the Pro-Ject PreBox S2 Digital by Crutchfield's James Ralston
Pint-sized audio precision
Use this little gem for high-fidelity sound with your digital audio sources, including high-res audio tracks. The Pro-ject PreBox S2 Digital measures barely over four inches wide, but it's big on flexibility. Use its stereo RCA outputs to feed pristine audio signals to a pair of powered desktop speakers or a power amp. Or connect your favorite set of headphones to the front-panel 1/4" jack.
Built to impress
The PreBox S2 Digital sports a dual mono configuration, with two high-performance DACs (digital-to-analog converters) onboard. It can play just about any high-res audio track you send its way, including super-high-res DSD files. There's built-in hardware support for MQA (Master Quality Authenticated) files, such as those available through TIDAL's streaming audio service. Jitter — digital timing errors that can smear musical details — is reduced to vanishingly low levels. It all adds up to surprisingly robust sound, given the PreBox S2's small size and reasonable price tag.
- dual mono circuitry with two high-performance ESS Sabre DACs (ESS9038Q2M)
- high-res audio playback, including PCM-based files up to 32-bit/768kHz and DSD512
- full hardware-based MQA support
- selectable digital filters
- vanishingly low jitter (as low as 100 Femtoseconds)
- full-color OLED display for volume, input, sample rate, and type of input signal
- frequency response: 20-20,000 Hz
- total harmonic distortion: 0.0003%
- headphone output power: 68 mW (32 ohms)
- 1 coaxial digital
- 1 optical digital (Toslink)
- 1 USB Type-B for connection to a computer
- RCA stereo output (rear-panel)
- 1 front-panel 1/4" full-sized headphone output
Dimensions & Warranty:
- 4-1/16"W x 1-7/16"H x 5-9/16"D
- weight: 21 oz. (without power supply)
- warranty: 2 years
- Our 60-day money-back guarantee
What's in the Box:
- Micro preamplifier
- AC adapter with attached 45" DC output cord and Micro-B USB plug (DC output: 5.0V 1.0A)
- 3 AC plug adapters (US / EU / UK)
- Wireless remote control (12-button)
- CR2032 Coin cell battery (for remote)
- CD with USB driver
- Instructions for Use (English)
- Instructions for Use (German)
Pro-Ject PreBox S2 Digital Reviews
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Overview: The Pro-Ject Pre Box S2 Digital is a high-quality digital micro preamplifier with dual D/A converters built in. This tiny package has USB, optical, and coaxial digital inputs, RCA analog outputs on the back, and 1/4" headphone output on the front. The Pre Box S2 Digital is available in silver and black, and comes with a 12-button remote control. Dimensions: Width 4.057", Height 1.457", Depth 4.783", Weight 13.3 ounces (w/o AC adapter).
Construction: The Pre Box S2 Digital features a dual mono configuration with two high-performance ESS Sabre digital-to-analog converters (ESS9038Q2M), capable of high resolution audio up to 32-bit 768kHz PCM and DSD512. Its proprietary clock circuitry delivers jitter rates down to 100 Femtoseconds. The Pre Box S2 Digital supports MQA decoding, which enables hi-res audio streaming. It also has a high-quality ESS9602 headphone amplifier. All of this technology is housed in an extruded aluminum casing.
Connections: The Pro-Ject Pre Box S2 Digital offers three digital inputs. The USB input is for connecting the unit to your computer. A USB driver is supplied on the included CD, if needed. The Optical and Coaxial digital inputs allow you to connect to components, such as CD players, DVD players, TVs, Audio Streaming devices, etc. You can select the input from the front panel, and the selected input will be shown on the 1" OLED display. The Pre Box S2 Digital has a stereo RCA output on the back panel and a 1/4" (6.3mm) headphone output on the front. When headphones are connected to the unit, the rear output is muted.
Sampling Frequencies: The Pre Box S2 Digital supports 32-bit PCM, DSD, and full MQA unfolding. The USB input is capable of the following sampling rates: 32, 44.1, 48, 88.2, 96, 176.2, 192, 352.8, 384, and 768kHz. It also supports DSD64, DSD128, DSD256, and DSD512. The Optical and Coaxial Digital inputs will support PCM up to 24-bit/192kHz.
Power Requirements: The Pre Box S2 Digital provides two options for powering the unit. If you are not going to use the USB input, you can power the unit via the included 5V AC adapter. If you plan to use the USB input, you can power the unit directly from your computer via the USB input. In this case, you should unplug the AC adapter to avoid interference between the two power supplies.
Digital Filters: The Pre Box S2 Digital has eight selectable digital filters, including Pro-Ject's proprietary Optimum Transient Digital Filter. Other available filters includes: Fast Roll Off (Linear Phase), Slow Roll Off (Linear Phase), Minimum Phase Fast, Minimum Phase Slow, Linear Apodizing, Hybrid Filter, and Brickwall Filter. These filters can be accessed from the front panel or remote to let you shape the audio precisely to your liking.
Front Panel Controls: The unit has a rotary volume control with a range of -80dB to 0dB. Pressing the volume control instantly mutes the audio. There are separate volume settings stored for the headphone output and the RCA output. Two buttons let you select the input (USB, OPT, or COAX), while a single button is for cycling through the available digital filters. The Menu button gives you access to settings for Distortion Compensation and Audio Quality, and displays the software (SW) Version. You can change the values for the audio settings by turning the volume knob while in the menu.
Remote Control: The included credit card-sized remote control gives you basic playback control of your digital music files, including play/pause, forward, and reverse. You can also raise or lower the volume, mute/unmute, cycle through the Digital Filter selections, control the balance, and access the menu. The remote is 1.58"W x 3.4"H x 0.29"D, and powered by a CR2032 coin cell battery (included).
- Frequency Response: 20Hz to 20kHz
- Output Voltage: 2.05 V (effective)
- Headphone Output Power: 68mW (at 32 ohms)
- Total Harmonic Distortion: 0.0003%
- Dynamic Range: 124 dBA
- Power Consumption: 5V, less than 1 watt
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