Pre Box RS2 Digital - Official Pro-Ject Audio Systems USA

The Pre Box RS2 Digital is the bigger brother of our award-winning and groundbreaking Pre Box S2 Digital. It uses the same excellent sounding DAC chips as the S2 version, proving once again that the Pre Box S2 Digital was already at the very top of high-end DACs and absolutely beyond its competition. Based on the same core design principles, the feature set is extended and driven to new heights. The result is a fantastic sounding and very versatile box. The perfect partner for the cream of the crop of high-end amplifiers and speakers alike!

The Pre Box RS2 Digital is a DAC and preamplifier that uses a dual-mono configuration of the highest-class D/A converters from ESS Sabre. ESS9038Q2M chips provide the highest sound quality in price-affordable, high-end circuits. Unlike most DAC´s in this price range, the Pre Box RS2 Digital includes dual DACs and separate signal paths for the left and right channels. Also thanks to these converters, the Pro Box RS2 Digital supports up to 32-bit / 768 kHz files in PCM and DSD formats (up to DSD512) via USB, covering any digital file you can buy or stream.

The analog output is a buffer that is both solid-state and high-quality tube. Thus, the customer can choose which of option is preferred. The Pre Box has eight digital filters. One of them is the proprietary optimal transient digital filter from the MQA creators. With these filters, the listener can customize the sound to suit their own preferences. Pre Box RS2 Digital comes with full HW and SW support for MQA technology (Master Quality Authenticated). In the Pre Box, the USB input signal is processed by a powerful multi-core XMOS microcontroller with advanced Multi-Core RISC architecture. The CPLD MAX II (Complex Programmable Logic Device) Altera is used for re-clocking, which together with the XMOS microcontroller brings high-quality processing of both classical and MQA technology. For the ideal use of this technology, it is best to connect the Pre Box to our Stream Box S2 Ultra in conjunction with the TIDAL service.

You can also enjoy MQA quality by linking it with our new revolutionary CD transport, the CD Box RS2 T. The CD Box RS2 T can be connected to the Pre Box by reliable I²S differential bus via the HDMI connector where the Pre Box RS2 Digital also provides the master clock (16.9344 MHz). The headphone amplifier is the ultimate design. No compromise. No coupling capacitors. Not even on the output. The amplifier is DC coupled. A very fast DC servo assures no DC voltage on the output. Its output power is suitable for all kinds of headphones. A premium full aluminum remote control is included in the packaging and the Pre Box RS2 Digital is available in a high-quality silver or black aluminum case. The big display screen on the front shows all relevant information in an easy to read, clean and structured way. Navigating the menu is very responsive and fast, allowing you to set up the unit to your preferences in seconds!

Additional information
Weight1.17 kg
Dimensions22.2 × 20.6 × 7.2 cm



  • Dual mono DACs: 2x ESS9038Q2M
  • High Quality optionally selectable upsampling of PCM and/or MQA content with proprietary filtering
  • Advanced re-clocking powered by new XMOS chip with Mulit-Core RISC architecture
  • 9 digital inputs: i²S HDMI, AES/EBU, Toslink, S/PDIF coax, Bluetooth v4.0
  • Analog: pre-out XLR/RCA/headphone, RCA input
  • Fully balanced dual mono design
  • Output stage switchable between 6922 tube & solid state
  • Ultra-linear and ultra low noise
  • New high-quality display with responsive and fast UI design
  • High quality full aluminium remote control included
  • Available in silver and black
  • Handmade in Europe


  • Frequency response: 20Hz – 20kHz (-0,3dB, -2,5dB)
  • Output voltage: 2,0V RMS – 0dBFS on digital inputs /RCA output, 4,0V RMS – 0dBFS on digital inputs /XLR output
  • Sampling rates: 32/44,1/48/88,2/96/176,4/192/352,8/384/705,6/768 kHz
  • DSD support: DSD64, DSD128, DSD256 and DSD512 (DoP, DSD512 native)
  • MQA support: full MQA unfolding by hardware for all digital inputs
  • Dynamic Range: 124dBA
  • Channel separation: > -117dB at [email protected]
  • SNR (20Hz – 20kHz): > 113dB at 0dB
  • THD: 0.005% solid state output/ 0.25% tube output
  • THD (20Hz – 20kHz): < 0.0003% @ 0 dB, 2V RMS, 1 kHz
  • THD+N (20Hz – 20kHz): < 0,0009%
  • Analog input sensitivity: 350mV
  • Line input impedance: 50kohms
  • USB data transfer : Asynchronous , DSD DoP up to DSD512 support and PCM up to 32b/768kHz
  • S/PDIF optical input: 2 x (24bit / 192kHz)
  • S/PDIF coaxial input: 1 x (24bit / 192kHz)
  • AES/EBU 1 x (24bit / 192kHz balanced)
  • I²S: for connection with CD Box RS2 T using supplied HDMI cable
  • Master clock output: 16.9344 MHz for CD Box RS2 T
  • Digital to Analogue converter: 2 x ESS9038Q2M 32-bit (dual mono)
  • Filter settings: 8x digital filter
  • Bluetooth version: Fully embedded Bluetooth® v4.0
  • Bluetooth music receiver codec: SBC, AAC, AptX
  • Output buffer: discrete and balanced, tube and solid state
  • Tubes: 4 x 6922EH
  • Headphone amplifier: discrete
  • Min. recommended impedance: 8 Ohm
  • Headphone output power: 90 mW / 300 Ohm; 245 mW / 33 Ohm; 150 mW / 8 Ohm
  • Display: 3,5” TFT module, 480×320, 360 cd/m2, contrast ratio 700, MVA technology
  • Balanced analog input: 1 x XLR
  • Unbalanced analog input: 1 x RCA
  • Variable balanced analog output: 1 x XLR
  • Variable unbalanced analog output: 1 x RCA
  • Headphone output: 1 x 6.3mm stereo JACK
  • Trigger sockets: 2 x 2,5mm 2-pole (1 x Trigger In, 1x Trigger Out)
  • Outboard power supply: 20V/3A DC, suitable for your country’s mains supply
  • Power consumption: max. 1A DC, <0,5W in standby


“The Pro-Ject CD Box RS2 Transport and Pre Box RS2 DAC punch way above their weight” – Steven Guttenberg, Audiophiliac

“Keeps up with the most advanced competitors” – Maxim Novik, TechWeek

“Throughout my listening, I was struck by how integrated, how completely together, music sounded through the Pre Box RS2 Digital” – Gordon Brockhouse, SoundStage

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