[Review] Pink Faun I2S Bridge - Computer to DAC Interface

Pink Faun I2S Bridge

The Perfect digital interface?

Product name: I2S Bridge
Manufacturer: Pink Faun - The Netherlands
Retail Price: €275 (Currency conversion)
(YMMV)

Reviewer: Mike Cox - TNT UK
Reviewed: June, 2014

Introduction

When the separate digital to analogue converter first appeared on the market the intention was to use it as an upgrade for a CD player. The input channels were mostly limited to SPDIF and TosLink, coaxial and optical. A while later people realised connecting the DAC to a PC so all the music could be stored, searched and then played, was a good thing. Some computers came fitted with SPDIF or Toslink outputs though they seemed to have not been widely used. The best in my experience has been the optical output on an Apple MAC.

A little while later, DAC manufacturers started fitting a USB input at which point computer based audio seemed to take off. USB was never designed for high quality audio data transfer. USB was just intended as a cheap way of connecting devices such as printers and external hard drives. The USB interface has evolved and is now on version 3 which is much faster and, as far as I am aware, is still not designed for audio use. With care, USB does provide a convenient and functional interface for audio, though in my experience it is very sensitive to the components involved. For a while, I have been using a MacBook Pro feeding data to my La Voce DAC. I used a Furutech USB cable and thought all was fine. I then tried the Chord Silver Plus which had good reviews and it would not work, the sound was heavily distorted. I then added a separate USB power supply and the problems went away, I could now use any cable I liked. Finally I added an iFI iPurifier at the DAC end of the USB cable, this seems to have cleaned up the sound a little.

This got me thinking that perhaps USB is really not the ideal computer to DAC interface. About the same time TNT-Audio was contacted by the Pink Faun team with the offer to review the I2S bridge. Fortunately my DAC does have I2S as an input using an RJ45 connector. The connection standard as prescribed by Pink Faun is HDMI. The team at Pink Faun were kind enough to make a special cable for me with HDMI at one end and the RJ45 connector at the other to fit the La Voce DAC.

The Manufacturer's Explanation

All audio digital-analog converters (DACs) receive their data in the I2S format. This is true for DACs with USB or S/PDIF inputs because the receiver chip converts the signal to I2S. With the I2S bridge, Pink Faun gives you a direct connection between a computer-based streamer and a DAC without any signal conversion. Any form of encoding / decoding that is applicable to other formats, such as USB, S/PDIF or Firewire, is a thing of the past, and sound quality is considerably improved. The Pink Faun I2S bridge is a PCI Express plug-and-play card. Pink Faun has chosen the Windows platform for the I2S bridge. Windows, as the most widely used operating system, offers a wide range of software packages for high-quality streaming, where the Pink Faun I2S bridge allows bit perfect transfer of audio media.

The I2S bridge is available in a 2-channel stereo and an up to 8-channel multi-channel versions. The maximum resolution supported is 32bit/192kHz on all channels. This allows the Pink Faun I2S bridge to be the next-step in streaming your favorite music as well as giving movie lovers a unprecedented and incredibly realistic audio experience. Surround sound via the SPDIF format (encoded signal transfer) is from now an outdated technique. By making use of the I2S format using the I2S bridge you can transfer surround sound without any conversion, direct to the DACs via high speed buffers.

The Pink Faun I2S bridge is based on a C-media multi-channel HD audio processor with a separate power supply, equipped with passive and active regulation. A TCXO clock with its own dedicated power supply provides a highly accurate master clock signal for the IC. HDMI cables are used for transfer of the I2S signal between the streamer and DAC. The I2S signal is also buffered with very fast low impedance line drivers. All capacitors used on the Pink Faun I2S bridge are high quality low ESR types. They are used in parallel for an even faster and cleaner power supply. The Pink Faun I2S bridge has its own power connector, so a supply from the motherboard is not necessary. Also the I2S bridge is equipped with capacitors that filter the PCI power supply lines, improving the computer's power supply.

Installation & Configuration

To use the I2S bridge a Windows PC running Windows 8.1 is preferred, although Windows 7 is also acceptable. I did not have a Windows PC to the right specification so I assembled one to the specification from the supplier. The motherboard is a Marshalltown Mini ITX with an mSata drive for the OS. The preferred configuration is for the music to be stored on a network storage device (NAS), something I have intended to do for a while. I used a cheap 3Tb NAS from Western Digital. The WD My Book Live is not particularly fast compared with the competition but seems fast enough. I did discover it was necessary to turn off all the cloud connectivity that allows you to access the drive remotely. With the cloud connectivity enabled the network performance dropped to the point it was unusable for audio streaming. [Stereo I2S Bridge]

The assembly and installation of the OS was simple enough. I strongly recommend Windows 8.1 over 8.0. Windows 8.1 takes up far less disk space and seems faster than the 8.0 release. Fitting the I2S Bridge after installing the OS is very easy and needs no drivers so the system was up and running very quickly. You could load on some music and start playing using Windows Media Player. The standard media player used by Pink Faun is JRiver Media Centre. The I2S bridge is compatible with all other players on Windows such as Foobar, XBMC, Jplay, iTunes, VLC etc. This is my first experience of using JRiver. Until this review I have been using Pure Music with the iTunes for the user interface on an Apple MacBook Pro.

Downloading and installing JRiver was was simple. The instructions supplied with the bridge making the setup straight forward.

Now that the basics were completed, all I needed to do was update the setting in JRiver to point it at the NAS and the folder containing the music. Once the basic setup is done there is a utility supplied with the bridge that you run to optimise the PC configuration. If you use the PC for other tasks you will find the configuration utility has disabled some parts of the OS not used for playing music so you will need to run another utility to return the setup back to the regular settings.

Whilst none of the installation and configuration is difficult, it does take time and a little care. The instructions supplied with the Bridge are perfectly adequate, even those in Dutch, as there are lots of screen shots. If you are not confident building and configuring your own PC the team at TripleMAudio can sell you the PC including the ideal linear power supply.

I started out using a switched mode 12v power supply for the PC then changed to a 12v linear as recommended. The setup now has no switched mode power supplies on the same circuit with the rest of the audio equipment. Finally, I made a couple of setup changes to the Windows 8.1 operating system. Firstly I made the system boot up without the new "Metro" interface. I also setup JRiver to run on system startup. Finally I managed, with some help from YouTube videos, to disable the login screen. The system now needs no monitor as it starts up without any prompts and loads JRiver.

File Formats

The JRiver media centre supports most file formats for the audio files. I started by copying my existing music files from my MacBook Pro on to the NAS. This library consists mostly of Apple lossless files with a few high resolution FLAC recordings. To help me add new CDs to the NAS I setup iTunes on my regular Mac to rip the files straight to the NAS. With this setup the music played nicely and it was easy to add new CDs. Pink Faun recommend using WAV format files ripped to 32 not 16bit, retaining the original sampling rate of 44.1Khz. To rip CDs to 32bit WAVs I needed a new ripping application. CD Ripper from dBpoweramp is the recommended solution. This application is only available for Windows PCs which meant installing on my new PC and, as this PC had no optical drive, I used a USB device. The only issue, which is obvious when you think about it, is the size of the resulting audio files. The 32 bit 44.1Khz files about twice the size of a regular 16bit WAVs.

After ripping a selection of my CD library to evaluate, I compared the result with the files from my regular library. The ripping process is easy and the technology used to determine the meta data for the CDs is excellent. It always found the correct track listing and CD artwork which is more than can be said for some ripping applications, especially on Linux. It was easy to switch between the two recording formats with only a few seconds delay. If I was starting out from the beginning, I would definitely use a PC with CD Ripper to generate my library in WAV files in 32 bit format. These larger WAV files seem to play with a quieter background, the sound stage seems slightly wider and with greater sense of height. As I have no intention of ripping my library again as it would take too long and I don't have enough disk space, this review was completed listening to my regular library.

Playing the Music

My reference for evaluating the I2S Bridge is my regular La Voce DAC fed data either from the I2S bridge or via USB from my MacBook Pro. To help the USB interface, I used an AQVox USB power supply and iFI iPurifier. The rest of the system consists of an MFA classic pre-amp followed by a restored Leak ST50 power amplifier and finally the Superioro single full range driver speakers on their dedicated stands. For me computer based music streaming has finally come of age. Connecting up the I2S device is simple and the impact on the sound quality profound, although difficult to explain. One of my reference pieces of music is the Allegri Miserere, regular readers will have seen me reference it many times. This recording has a wonderful if slightly hazy ambience, it is hard to localise the singers in the sound stage. With the I2S bridge it is easier to locate each of the singers. The Bridge also seems to deliver that hard to quantify musicality, everything seems to sound right, not processed or digital.

For me, the timing of the music is very important, all the instruments and singers must appear at the correct time. When it is done correctly the difference it makes is special; this includes transients such as the kick of the drum. I sold my previous speakers because they sounded slow.

This new sense of musical timing had me searching through my library for more great rhythms. It was hard to stop, and it was only the lovely sunny bank holiday weekend that drew me away for a short period. When I returned, I rediscovered Ibrahim Ferrer on the album Buenos Hermanos with some great Cuban rhythms. This then led me to Buena Vista Social Club album with more Cuban musicians. As well as the great musical beat the texture of the vocals was richer, the voices sounded deeper and with more body. When I recently reviewed the Sparkos Labs discrete operational amplifiers fitted into a Maverick D2 DAC the La Voce DAC via USB was out played. The sound of the Maverick D2 DAC with the Sparkos op amps took on more body and soul of the music. Changing the interface to I2S the La Voce stepped up a gear and now out classed the Maverick D2 plus upgraded op amps. The high frequencies, particularly from the percussion were cleaner, smoother and more realistic. I hate the word "musical" but that is a good description of the change.

Conclusions

Not all DACs provide I2S as an input channel, though it is becoming more widely available. The HDMI connection standard does support 2 channel using I2S. Pink Faun have their own range of DACs that support I2S over HDMI. If you are about to upgrade your DAC solution I strongly recommend searching out a DAC with I2S input and then talk to the team at Pink Faun about the I2S bridge. The bridge will not make a silk purse out of a sows ear, when the recording is poor it will remain so. When the recording is good the I2S lets the quality through. As an example one of my favourite tracks from Led Zeppelin is "Whole Lotta Love" and my version is on the Early Days CD set. No matter how this track is played the sound quality is, to my ears, poor. Conversely "Stairway to Heaven" off the same CD is way better and with the I2S Bridge this quality really shines. The recorders and guitar on the slow intro are delivered with tremendous richness of tone. The improved separation of the instruments makes the two recorders much easier to hear.

The I2S Bridge will not suit everyone as it is only available for a Windows PC. Even with this limitation the solution is worth seeking out and hearing. I will use I2S for the interface whenever possible. In my experience USB is still a long way from perfect as a transmission medium for audio data.

Compatible DACs

Pink Faun
Sonore
Wyred4Sound
PS Audio
K&K Audio
Audiobyte
Wadia
Love Harmony
MSB Technology
Empirical Audio
Northstar Design
LKS Audio
Ayon
Stello
Audio Alchemy
Perpetual Audio
Camolot
Aquasound
Audio-GD

This experience of using I2S in place of USB has shown that other manufacturers of DACs should be considering this interface.