HDMI cable for I2S
I’ve got an old Oppo DV-970HD I’m using as a transport into my Musician Pegasus R2R DAC in my headphone rig. The Oppo has an HDMI out (that does output 2-channel PCM) and the Pegasus has an HDMI I2S input, so I was wondering if any HDMI Cable will work for this? I recall someone saying you need to check with the DAC manufacturer to see which pins are live, but just wanted to check here to see if I’m missing something or if this can even work. I’m thinking of getting a 0.5m DH Labs Silversonic HDMI 2.1, so would this cable possibly work for this? It’s marketed as a video cable so not sure if that means anything or if HDMI is the same for audio or video. Thanks for any help/insights.
yes, there is a difference (that is if you are actually using a real i2s output board on the Oppo). I2S is the native PCM bit information for each channel. There are two separate channels that require two different connection. S/PDIF will take the 2 channels of i2s data and encode it all into a single bitstream. It is clocked the same, but transmitted over a single wire. At the receiving end, the device has to decode the bitstream and separate the data out into two i2s channels again. This raw i2s data is what is sent to the DAC chip.
If you use the standard HDMI video output of the Oppo, you need to connect this to an A/V pre/pro or receiver. The Oppo will take the S/PDIF data and break it into HDMI data packets (essentiall de-clocking the S/PDIF signal because the data packets are merged into the HDMI audio/video data using HDMI clock signals). This is what is called PCM-over-HDMI. The pre/pro or receiver will have to extract the audio data packets and re-clock that into the proper PCM sampling rate before sending it to the DAC. If you compare PCM-over-HDMI with a normal S/PDIF coax connection, the S/PDIF coax will generally be superior and have much more dynamic range and better sound. |
@auxinput is correct and the HDMI input on your DAC has nothing to do with the HDMI output on your Oppo. They are two different animals. They are the same physically but the type of signals they require are completely different. Do not plug one into the other. If you want to use the HDMI input on your DAC you need the Oppo I2s card, no ifs or buts or whatevers. The HDMI output on your Oppo transmits Video and Sound for watching movies and as Auxinput correctly said if you decode the sound from this HDMI cable it won't be better than COAX. |
The crux of the matter when connecting different brands via HDMI I2S is pinout matching since there is currently no standard. Assuming the output is in fact I2S since they HDMI terminals visually look similar. I'f I'm not mistaken the Pegasus has the ability to accommodate several options to match the I2S pinout of other equipment. Check with Musician or the web as I've seen a diagram posted.
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