I haven’t seen any dedicated DAC’s with HDMI input, only as part of something else like an A/V Receiver. Which DAC are you planning to use?
Little longer; i2s is an Inter IC Sound serial bus interfacing standard (http://en.wikipedia.org/wiki/I%C2%B2S) and a different standard than HDMI. HDMI supports interfacing for more purposes than only between sound chips (like video, network, etc. and audio).
PS Audio for example offers I2S over HDMI inputs on it’s DACs and equivalent outputs on it’s transport. They in fact defined the “standard” for I2S over HDMI.
It’s only the physical cable and connector used for signal transmission and has nothing to do with the embedded audio signal of the HDMI protocol. Instead a differental current signal is used for each I2S signal (SDA, LRCLK, BCLK, MCLK).
Other solutions are using Ethernet connectors and cables or BNC.
I took from the webpage of the thread starter that he’s using Audio GD DACs from China. Audio GD is also offering I2S over HDMI modules.
The only problem with the RasPi is, that it doesn’t provide a MCLK. So it needs some sort of clock recovery or upsampling on the DAC to get it running without it. The SABRE chips used by Audio GD as well as by many others perform such a clock recovery. So I’m pretty sure that this will work out of the box, as long as you connect the IIS signals from the RasPi’s P5 connector in the right manner.
yesterday I received my new dac, It’s a Audio-GD Master 7 with I2S HDMI input
Now it’s playing with a i7 passive cooled pc, with a Pink Faun I2S Bridge, which works very fine
but the I7 consumes too much power to leave it on almost the whole day…
The Raspberry would be better for this job, but after reading your answers the sollution must be found in an
extra addon board with I2S HDMI output and master clock?
Connecting this board to the Pi should be an easy job.
As I said Audio GD uses SABRE chips on most of it’s products. So no Master clock is needed. BUT(!) the Master 7 you use has a PCM1704 DAC and I’m not sure if this works works without the master clock. Check the datasheet or ask Audio GB. They should know.
it depends on the converter chip your DAC uses. The SABREs as well as the often in RasPi add on modules like HiFiBerry or IQaudio used PCM510x or PCM512x chips don’t require a MCLK as they recover it from the BCLK.
I had a short view on the datasheet of the PCM1704 being of interest here. It also only needs the LRCLK (WCLK), BCLK and SDATA. So it might work also. But it’s pretty much limited on the data formats and to 96kHz max. SR. It’s an old design… Pay attetion that this is a pure DA converter w/o any upsampling or digital filtering. So there may be a digital filter used in front of it.
Regarding the PS Audio PWD II, I got the information from Paul McGowan that no MCLK ist required as long as the SR converter is used. Only the Native modes require a MCLK. For the new Direct Stream no MCLK in general is needed as the FPGAs transfer all incoming data to DSD. I ordered a I2S over HDMI module made by Aune from Audiophonics, but it turned out to be a receiver. Short after they took the Audio GD modules into their shop. I have to get one first, before I can report.
I’m very interested in this experiment of yours! please keep us posted about the outcome.
I too want to use my Pi as source to feed and I2S DAC with hdmi connection (PS AUDIO)
Just tested my I2S output (hdmi format) and it worked!
Bought the output module from Audio-GD and connected as such:
BCK -> pin 12
MCLK (master clock) -> grounded on pin 34
WCK (LRCLK) -> pin 35
Data -> pin 40
Ground -> pin 39
Power : pin 1 (3.3V)
selected standard I2S output in volumio and voila!
played 24x192 but won’t play DSD. I have a problem on my Pi with DSD, won’t play anymore even with the iQaudiO dac I tested successfully before so maybe that’s not the last of it ;o)
that’s encouraging, just have to make a HAT card with I2S hdmi out now!
for the moment it’s 10cm just female jumpers, I don’t remember where I got them from but they are pretty standard. The 3.3V power was already soldered to the Audio-GD board so I had to attach a connector to the other end from an old stock of when I was a student ;o)
As you can see I did not short the MCLK this time, still worked. Will do in the future !
I just bought one of the boards from Audiophonics. I’ll try and send the I2S signals out to my wyred4sound DAC2 SE from my Pi 2. Probably will take a month for the board to get here; I’ll post after that, if I don’t get something else going sooner.