Pro-Ject Pre Box S2 Digital
Pro-Ject Audio Systems is known as the world leading producer of audiophile analogu hi-fi turntables for more than 25 years. Therefore the company is very proud to introduce their new outstanding pre-amplifier with class-leading features and sound at a very reasonable price. Pro-Ject sais that the Pre Box S2 Digital is not just another product, but a milestone in design. The dual mono configuration with flagship D/A converters from renowned manufacturer ESS Sabre delivers a highly enjoyable and engaging yet crystal clear, transparent and informative sound. The ESS9038 Sabre DAC is a high-performance 32-bit digital to analog converter and uses ESS's patented 32-bit Hyperstream II modulator architecture and Time Domain Jitter Eliminator. It delivers an unprecedented dynamic range of up to 129 dB and THD+N of 120 dB, a performance that will satisfy the most demanding audio enthusiasts.
Pre Box S2 Digital is also the first product of Pro-Ject's line-up to support hardware MQA unfolding. MQA (Master Quality Authenticated) promises to deliver a sonically superior experience while in a smaller file size so that amazingly high-quality audio can be packed into files small enough to easily stream or download. Pre Box S2 Digital offers full high-resolution audio playback of PCM files up to 32bit 768 kHz and DSD files up to DSD512. Ensuring a future proof solution for all existing and incoming digital audio files.
With a total of seven digital filters, including Pro-Ject's proprietary Optimum Transient Filter, Pre Box S2 Digital guarantees different sound experiences to meet the high tastes of any audiophile. Pro-Ject's custom digital filter offers optimum time domain performance and outstandingly accurate timing with zero ringing. Passive components are also from highest possible class (organic polymer capacitors, ThinFilm miniMELF resistors). Polypropylene film capacitors are used in the PSU and signal path. Organic polymer capacitors are very low thermal drift which results in consistent playback performance and is critically important for positions like the analog power supply. The used ThinFilm miniMELF resistors have very low voltage coefficiency and deliver an undisturbed sound without impurities.
Pro-Ject is using a 16-core XMOS chip for asynchronous USB data transfer and full MQA hardware unfolding. The DAC directly controls the XMOS chip. A four layered, gold plated PCB with extra shielding is used to achieve optimal audio performance. The clock circuitry is Pro-Ject's proprietary design and can easily compete with renowned and respected audiophile clock generators. Digital audio is the art of time, a high precision clock is needed to produce a certain lifelike presentation and only with a great clock, you can manage accurate sound. Pro-Ject's proprietary clock design is the basic stone of Pre Box S2 Digital. This design will get adapted to all Pro-Ject's products.
Measured jitter is lower than 1 picosecond and typically can be about 100 femtoseconds. The synchronization of all internal oscillators is an often overlooked and extremely important feature. Imagine an orchestra without a drummer or without the conductor. Every musician plays in his own rhythm and tempo, the result is pure chaos which nobody can listen to. The same applies to oscillators in a DAC. There are a lot of oscillators with different frequencies and they start to talk chaotically - what could be the outcome? The absolute opposite happens when all oscillators are perfectly synchronized, like in Pro-Ject's Pre Box S2 Digital, and work like an orchestra with the perfect conductor. This results in low jitter, minimizing interference and in wonderful sound.
One of the major problems for USB DACs is the transmission of unwanted noise coming through the USB output. A lot of research of Pre Box S2 Digital went into how to make this noisy connection quieter. After a lot of head scratching and trial and error, Pro-Ject found the solution to lie in active and passive filtering of the output. After applying passive RF interference filtering the results are already remarkable. Noise on 1 kHz drops to -125 dB, at 10 kHz noise comes even close to -160 dB. But they improve even further when applying an active filter after the passive filtering. The results are limited by the capabilities of the measuring equipment and noise floor lays at -160 dB or even lower. There are visible peaks at 50 Hz and 100 Hz which are caused by limits of the measuring instruments. However, they are at a level of -130 dB and -140 dB.
Pre Box S2 Digital marks a new era for Pro-Ject's S-series components and sets a new benchmark for future products. It offers revolutionary circuit design, future proof specifications and most of all - outstanding sound and value. The casework is done with massive aluminum to give an elegant appearance of high value but also to avoid any electrical or mechanical influences. Pre Box S2 Digital comes in aesthetic matte silver and black. Pre Box S2 Digital is available in silver or black at an SRP of €349. Info and photos by Pro-Ject Audio Systems.