I would like to ask for some advice or guidance. I was hoping that the I2S capability of the new VanityHD card for the Oppo 203 would include an HDMI port, so I could run directly to a DSD with a good HDMI cable (my current set up is stereo). When I asked awhile back, the company didn’t know, and now the manufacturer has just posted that the I2S will be “an on-board 14 pin IDC header with 8 channel I2S output, master-clock signal, ground and 3V3 power signals.” Given that in principle I2S sounds better than coax, my questions are 1) whether or not the mod proposed is likely to be worth it sonically, and 2) what do I need to know specifically to make it work with the Directstream. I’ve just asked if there are any step by step instructions to determine if I can handle the mod myself or will need some help. I haven’t received the board yet, but it is expected to ship in the U.S. next week. Currently, I’m running a Snake River Boomslang s/pdif between the units.
There’s a forum post from the manufacturer that goes into some details, which I’ve copied below. Here’s a link to it: http://www.audiopraise.com/forum/read.php?13,838,840#msg-840
And the I2S page from the manual: https://1drv.ms/i/s!AqsCKHVTj0ydlQ3titt-SeGttch8
There have been some questions how to connect the I2S output from the Vanity203HD board to a DAC with I2S input via HDMI or RJ45. Let’s recap the I2S port description from the user manual:
For added flexibility the Vanity203HD features an on-board 14 pin IDC header with 8 channel I2S output, master-clock signal, ground and 3V3 power signals.
The master-clock signal is either 22.5792MHz or 24.576MHz depending on the base sample rate. The audio channel assignment across the SDATA signals is the same as the channels order at the main S/PDIF outputs. SDATA1 contains both front channels, SDATA2 carries the surround channels, SDATA3 carries the center and subwoofer channels and finally the SDATA4 contains the surround-back channels. The I2S output has standard 3V3 LVCMOS signaling levels. If the downstream DAC accepts different signaling type or levels (e.g. I2S over HDMI or I2S over UTP/STP Ethernet) the user has to provide a suitable conversion circuit.
There are two reasons why we didn’t include a HDMI (or RJ45) connector with I2S signals directly. First, there is no unified pinout standard for I2S over HDMI. Different DACs have different pins assigned to different signals which makes it impossible to come up with something that would work for everyone. Second, there is no room or cutout for the HDMI connector in the back panel and we really wanted to keep the board as a drop-in replacement for the analogue board without any mechanical modifications.
But, if you want to use the I2S output, you can!
Electrically as well as mechanically the I2S requires just a bit of DIY. In order to feed your DAC with I2S you need a level converter module to convert standard 3V3 LVCMOS to HDMI signals (LVDS). The Vanity203HD has been tested with Audio-GD I2S module and this module is used as an example in the connection diagram below.
The user has to make a custom connection between the on-board IDC connector and the HDMI output module. Please note that the signal assignment must match with the one on the receiver side and there is no universal guide for that. Always refer to the manual of your DAC.