The Sonore Rendu is an audiophile network audio player with Ethernet input
and SPDIF or SPDIF/i2s output. The Rendu is intended to operate in combination
with a DLNA server running on your PC, Mac or NAS. You then control the
Rendu from your hand held mobile device application.
What makes the Rendu different from a computer music servers is that it's a purpose built audiophile device. The problem with computer music servers is that they all rely on mass produced mother boards designed for general purpose computing and are built to the lowest possible price point. The Rendu solves this problem by removing the consumer grade computer peripherals and switching mode power supply from the equation. The Rendu's main board has been specifically built for processing audio signals perfectly. The Rendu is powered by an audiophile grade linear power supply with a high quality ultra low noise regulator. The Rendu also operates asynchronously using on board fixed frequency low jitter clocks to achieve the lowest possible jitter.
We looked at the standard Rendu, already providing fantastic performance in many systems, and thought hard about how it might be improved, how we might lower jitter, and improve on its digital precision. We decided the correct way to go would be to upgrade all facets of the design making incremental improvements which add up to considerable performance gains. The power supply is upgraded both in parts quality and layout. The big addition is the new isolated, clock/re-clock, output board. By specification, the Ethernet input is already isolated from the noise on the network, but there is still some noise produced on the processing board. To generate an absolutely pure clock signal, we added a separate, isolated, output board with a separately regulated power supply. This output board holds the dual Crystek CCHD oscillators, the re-clocking circuitry, and the output drive circuitry for SPDIF and I2S. Because the Signature Series Rendu generates clean clocks and then reclocks on the output board right before the SPDIF and I2S output jitter is lowered even further. Additionally, a very special SPDIF driver circuitry results in a perfectly clean SPDIF waveform which allows one to get the best out of any SPDIF input DAC. While the original Rendu has set the Ethernet to SPDIF and I2S standard up to now, the new Signature Series Rendu takes performance to the next level, this is the best SPDIF and I2S we can make, and we suspect that you will think so as well.
The Sonore USB to i2s interface is a high performance DXD/DSD128 capable
asynchronous USB interface designed for DACs using the ESS Sabre chip.
The asynchronous USB receiver is powered from USB allowing for complete
isolation of the oscillators, re-clocking and oversampling/filtering (including
ground) from the source. Crystek CCHD series ultra low phase noise clocks
are used for the lowest possible jitter. On the "clean" side of the board,
the Crystek oscillators (45.1584/49.152 MHz), the FPGA running the oversampling
filter (OSF) and the re-clocking circuit, are powered from a user provided
~5 VDC source.
A unique feature of this interface is the (optional) onboard OSF. This filter oversamples to 352.8/384, using specially developed proprietary digital filters. The filter design takes advantage of the high power available in the FPGA to incorporate a sophisticated partial minimum phase filter, which greatly reduces pre-ringing, while still providing excellent stop band rejection (anti aliasing).