HDMI vs I2S Audio

Paul clears up some confusion between HDMI and I2S as a means of transferring digital audio data and the playing of SACDs.

[gotham]

The Jay’s Audio CDT3 transport has a HDMI connector output that conforms to the PS Audio format.

[ptg]

Denafrip's DACs that have I2S using HDMI has pin-outs that are 'configurable' and supposedly will work with PSAudio's SACD Transport. Never tried it though....

[carlstineman]

Not sure Paul got to the core of the problem Chris, the questioner, was asking about. In order to encourage copyright holders to allow their music to be published in the DSD format on SACDs, Sony encrypts the DSD layer on commercial SACDs. The DSD signal can only be decrypted to an I^2S format by a module included in an onboard DAC supplied by Sony that many SACD players use. Unfortunately that DAC is of indifferent quality, hence the desire to export the I^2S signal to a better external DAC. I own an OPPO 103D SACD player, and, like Chris, hoped to export the unencrypted DSD layer to an external DAC. After carefully reading the OPPO's owner's manual, I discovered that the OPPO is unable to export the unencrypted DSD signal (I^2S) via any of its digital export ports (USB, optical, HDMI, etc.) due to the music copyright protection provisions built into its DAC chip. PS Audio is able to isolate and export the unencrypted I^2S signal from its transports to one of its separate DACs while still complying with SONY's copyright protections by using a "handshake" arrangement between the transport and the DAC that ensures that there is no equipment capable of recording the unencrypted digital I^2S signal in the transfer path, the main concern of the copyright holders. So, I believe, PS Audio DACs can only accept unencrypted I^2S signals via an HDMI cable connection from a transport capable of this "handshake" arrangement. Paul described this transfer arrangement in an Ask Paul segment several years ago.

[IndySnowman]

I’m using a Nuprime CD transport with I2S to a Stellar Strata. Works great.

[blastfromtheeast]

That was educational. I was not aware of Hdmi pin config vs. I2s pin config until I saw a post by Poetry on plastic mainly cause my system uses built-in dac of my integrated amp and built-in dac of my sacd player. Buyimg a dac to upgrade sacd output is a bit more challenging than it looks. I also read on a forum that plugging in hdmi to an i2s port might damage the circuits which worried me more.

[carminedesanto]

Great explanation..I was under the impression that an output of I2S was to be fed to a reclocker and then to the dac 🤷🏻‍♂️

[roybatty-]

Why aren't more amps incorporating hdmi? And why hasn't the look of AVR's changed since 1990?

[darrelstucky]

I am using an OPPO 103 that has an I2S modification (OPPOMOD) to output I2S audio to my Stellar Dac, and it works and sounds fantastic!

[odizcvw]

Perhaps I misunderstood, but when Paul implies that PS Audio invented I2S that is not true. Perhaps he is saying that they were the first to use an HDMI cable to transport I2S data between devices. I2S was introduced in 1986 by Phillips and is used by virtually every DAC chip since to accept clock and signal data into the chip. Within a DAC or a CDP I2S often travels on a ribbon cable, a pcb trace or ufl coax cables. Typically the signal is not durable for more than a few inches. I imagine PS Audio decided to use HDMI cable is for connecting separates like the transport to DAC to move I2S over longer distances.

[roig]

You can try a DDC from Denafrips (Hermes model) or Musician Audio (Leo model), which has a configurable I2S output, and adjust the I2S configuration in it to match the Gain Cell DAC I2S configuration. I have never done it, it but could be possible.

[kevinsilvernale]

Jay’s Audio transport implements I2s as well.

[coastalvideotransfer]

I wonder if you can get a converter box that turns spdif to i2s and reclock it and send it to the dac.

I remember Paul talk about it

[ThinkingBetter]

Best is to let the DAC manage the clocking of samples precisely and enable the buffering of the digital audio data flow on the receiving end of the DAC such that you avoid jitter effectively. In the past digital audio was done with messy architectures where the DAC clock master was not located where it optimally needs to be located (= inside the DAC) and thus the DAC was not fully in control of the DAC timing e.g. PLL was needed with TOSLINK. USB (best is USB-C) is excellent in managing the digital audio flow asynchronously allowing the DAC to be clock master. I don't really see the light in I2S used externally other than for the specific case of using a CD player (or call it transport) where the disc player runs at its own clock, you can use I2S to shift the clock master function to the CD player. Better would be to use a USB connection and run the data asynchronously with the DAC in 100% control of the timing of sample conversion.

[andydelle]

Paul, using the HDMI connector for I2S was a great idea. And as we know I2S is not compatible with HDMI. But I am curious if you are using standard LVDS HDMI cable interface chips or are you just using the HDMI cable and some other balanced signal technology like RS422?

[davemeyers]

Project has a Transport that outputs I2S over a HDMI connection, Not sure if it is pin compatible. but they do have one

[AV-MusicMan]

With the oppo, you can rip the sacd dsd layer to a dsf file. Then you can play on any cd player and dac combo. The HDMI is the physical cable connection and only ps audio dac with sacd capability can decrypt the signal in the other side of the cable. That creates the closed loop Paul is referring too. It is a common misconception to think that you can export sacd dsd layer to a external dac via an sacd player like oppo 105. What I do to get around this is take the oppo 105 and use an internet hack to rip the dsd files in sacd to dsf file(s). There is a usb boot disk that does this. Then I convert that dsf file to wave format. Then I burn the wave files to dvd or cd and play on ps audio perfect wave transport to Berkeley dac. The perfect wave or direct stream can play wave files on either dvd or cd, so it’s really handy! Voila, sacd layer exposed!

[Scopolamine]

I'd like to know why you made your own HDMI standard when it already has a pin out that is it's standard.

[chrisgregory]

Would one of those $60-100 HDMI-to-I2S converters found on eBay allow you to connect your SACD Player to the PS Audio DAC?

[RuiChambel]

Oppomod makes/sells a i2S card upgrade for the Oppo 93/103/103D and 203 Blu-ray players, but some assembly is required

[leslieschroeder]

Hi I own a cd transport from Jay’s Audio. That transport does use isquard s2: CDT 3 mk2