Is I2S Standard?

Thinking of a transport with I2S, hdmi output, I’m wondering if it’s a standard, i.e., can I be assured that it will communicate perfectly with my DSD?

No unfortunately not.

Here’s a spread sheet with some of the more common I2S connections. The HDMI page is what you want:


Wow. That’s an amazing list, Ted. Thanks!

Jesus of Sonore has kept expanding it. He even proactively ask me a long time ago how the DS differed from the PWD so he could update it.


With TJ’s help, I got the same list but missing is the I2S pinout from the MiniDSP output to the PSA DS Sr. I2S. I’m hoping to have it done this weekend and add it to Ted’s Spreadsheet. I’ll post the pinouts once I’m successful.

I am (was?) considering using a Matix X-SPDIF 2 to convert USB out on a Pro-Ject Stream Box S2 Ultra to I2S on a Stellar GCD + S300, so I can playback native DSD instead of DoP.

Then someone pointed out to me that many devices with I2S out are limited in resolution (below the capabilities of the SGCD). Does the Matirx X-SPDIF 2 ( fall in that category? The specs are not clear to me.

Is it worth the cost (600 with a good power supply) and the hassle? In case you want to apply the law of diminishing returns, my whole setup (excluding Mac Mini with Roon Core) costs about 6,000,-.

Thanks in advance for your expert advise.

The Matrix can do higher I2S rates than the SGCD (or DS and DS Jr) can handle - I’ve been very happy with mine.

1 Like

Thanks for the feedback.
One more question: I know experts prefer to avoid making specific claims about gear performance. But in your opinion, should I expect an improvement in sound quality when converting the Stream Box USB output to I2S to feed the SGCD compared the direct USB connection. Or are there too many variables to consider in order to make a prediction?

I think most people would hear a difference - an external linear power supply (not a wall wart) for the Matrix might make an additional difference. I got my Matrix for the extra flexibility with the multiple output formats, but the difference in sound quality, while not entirely unexpected, was welcome. There are a lot of people happy with their Matrix and many have some strong opinions on further refinements over on the Matrix thread, but IMO you don’t need to go to those lengths to enjoy an improvement, but if you enjoy tweaking there are a lot of examples. It’s also a physically nice piece of gear, well designed and well implemented.

1 Like

Whenever you have a moment Ted, please have a look at my Post
HDMI to I2S Adapter Board

Please give me your honest opinion. I do hear an improvement over both Direct USB and Coax (S/PDIF). Temporarily, I connected a cheap optical cable over twenty years old and that connection sounds pretty good playing back CD’s and streaming online videos.

Thanks for what you do,

Ted, is there a recommended HDMI cable length for IS2? I have two cables I can use. Both are Wireworld Platinum. .3M and 1 meter. If I swap the cables there is a slight difference in sound between the two. The 1M seems to have a tad more depth and detail. Am I imaging this?

No you’re not. I too have both the .3m and 1m Platinum S7 HDMI and the 1m does sound richer. The .3m sounds slightly dryer. The difference is very small and you really have to concentrate to hear it, but it’s there. I think that’s why some company recommends a certain length for their cables.

1 Like

In an ideal world it wouldn’t matter. The signals balanced and are carried on differential pairs and an HDMI cable that meets the HDMI specs has a 100 Ohm differential transmission line impedance. The DS properly terminates that signal which should result in minimal digital waveform distortion.

Many Audiophile cables don’t match the specs for HDMI cables (or USB, etc. for that matter). With such cables the length matters: the ringing on signals can definitely cause a lot of jitter and noise. Some may hear this as more definition or more air, but that’s a euphonic distortion.

I simply recommend using your ears to get the sound you like.

So Ted, are you saying then shorter is actually better then? Maybe not as pleasing, but more accurate? Or try to buy a cable length that has 100 ohm at desired length?

No, I’m saying that with an expensive (but not entirely within the HDMI spec) cable length can matter, but the best length isn’t obvious. With a standard HDMI cable length doesn’t matter as much. Other differences, e.g. grounding configurations probably make a bigger difference than length (at least with a DS.)

1 Like

Thank you Ted. Please please be as safe as possible right now during this period in the world. To you, all your friends and family, plus everyone at PSA!

1 Like