HDMI to IIS/Coax DoP Converter

[amirm]

This is a review and detailed measurements of an HDMI to Coax/Toslink and IIs interface converter with support for DoP format. It was kindly drop shipped to me by a member and costs US $103.

As you see, there is no brand name on it. Here is a link to the ebay listing: https://www.ebay.com/itm/353354399159

Member wanted me to test its performance while sending DSD data over HDMI but alas, I have no ability to generate such test signals. What you are about to see is its performance while carrying PCM data in the form of J-test signal.

There is facility for external 5 volt input but no supply was provided. So I let it get self powered from HDMI source.

HDMI to IIS/DoP Converter Measurements
Let's start with the dashboard of capturing jitter and its spectrum over Coax output (input is from HDMI):

Peak jitter level is 2 nanoseconds. As a way of reference 0.5 nanoseconds is enough to equate the amplitude of the lower order bit in 16 bit content. So this is not good at high level. FFT spectrum shows that majority of that is mains noise at 60 Hz. That jitter will perceptually get masked so it is not very important (indeed, the above measurement has 700 Hz high-pass filter per AES standard). There are also high frequency component around 100 KHz.

Let's compare its performance to that of Topping D10 acting as a bridge between USB and S/PDIF:

We see that this HDMI converter has broadband noise that is much higher than Topping. HDMI interface has a lot of jitter since it is made primarily for transmission of video. Without proper clock regeneration it is liable to have such performance issues.

Conclusions
Use this box for convenience of converting one format from another, not for performance reasons.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[TheWalkman]

I’ll stick with two paper cups and a string.

 

[AdamG]

More of a Description than Specifications. But it’s all I could find: Thank you for the review Sir. Just another Monday to you isn’t it?

When you are trying to just separate the Audio for basic utilitarian purposes to feed into some older kit that predates the HDMI standard. This will get the job done.
With that in mind, I gave it a Not Terrible rating.

 

[sam_adams]

Shortest review ever?

 

[JDS]

What is the use case for this device?

 

[Blumlein 88]

I suspect bias on the part of the reviewer. He used ugly disturbing red for the jitter of the device and a calm blue for the other. Leading many to see this graph and hear a reduced sense of layered soundstage and 3D spatial quality. Tsk, tsk!
/sarc

 

[juliangst]

Are there any alternatives that have better HDMI to SPDIF jitter performance?
A lot of modern devices like some smart TVs, Apple TVs, consoles or PC motherboards don't come with SPDIF outputs anymore so it would be useful to have a good converter for that.
If this kind of jitter is even audible is a different topic but having an objectvely better converter would be welcome

 

[amirm]

Are there any alternatives that have better HDMI to SPDIF jitter performance?

I have tested a few. I don't recall any standouts. Good news is that DACs are pretty good at filtering jitter so what is measured here, doesn't impact them much.

 

[amirm]

What is the use case for this device?

Usually to extract audio out of HDMI to use with typical 2-channel system that lacks it. This one is even more niche in that it allows DSD stream over HDMI, e.g. out of an SACD player, to be extracted and transported over IIS to many DACs that support it.

 

[Stoutblock]

I (and many others) use one of these for a very specific purpose where we have very limited options. If you have a SACD player, but you don’t want to use it’s internal DAC, this box allows you to send the SACD stereo signal to an external DAC capabile of playing DSD files. The SACD player has to have an HDMI output (like most Oppo players for example) that you use to send the signal to this box. You can use the box’s i2s output to a DAC that has i2s input or you can use the box’s SPDIF output to connect to a DAC that has DoP capability. In either case the DAC will recognize the signal from the SACD player as DSD64.

 

[tjf]

Here, read this nugget of semi professional audiophile reportage from Mssr. Graves from 2021....about sending I2S DSD content to your I2S input equipped DAC:

At Long Last! Listen To Your (Physical) SACDs Through an Outboard DAC

At Long Last! Listen To Your SACDs Through an Outboard DAC George Graves When Sony/Phillips Announced their new Super Audio CD format (SACD) in 1999/2000, Sony opened a marketing office in NYC to advertise and promote the new format. They reached out to a number of audio writers (including, yours...

audiophilestyle.com

 

[linger63]

Been using one of these for a while now with absolutely zero issues.

 

[gvl]

Usually to extract audio out of HDMI to use with typical 2-channel system that lacks it. This one is even more niche in that it allows DSD stream over HDMI, e.g. out of an SACD player, to be extracted and transported over IIS to many DACs that support it.

The SACD use case is mainly why these devices are getting attention. At least there’s DOP in this one, but earlier devices only had I2S, so all this jitter would go direct to the DAC chip. Can we speculate about how much this jitter affects DSD streams? In any case using internal SACD DAC strikes me as a much better idea than this device and an uber external DAC.

 

[Talisman]

Are there any alternatives that have better HDMI to SPDIF jitter performance?
A lot of modern devices like some smart TVs, Apple TVs, consoles or PC motherboards don't come with SPDIF outputs anymore so it would be useful to have a good converter for that.
If this kind of jitter is even audible is a different topic but having an objectvely better converter would be welcome

https://www.audiosciencereview.com/...amazon-basics-4k-hdmi-extractor-review.39467/

The Amazon basic converter showed perfect pure digital extraction performance

 

[Beershaun]

I am tired of seeing shit HDMI implementation. I'll give it all a poor if they can't achieve a simple goal of filtering out added noise. Maybe I don't understand something that makes this hard with HDMI.

 

[amirm]

In HDMI, the audio clock is derived from video. Video signals are immune to jitter as the pixel position is fixed (was an issue with CRT terminals). Audio was an afterthought and added in spare scan areas of video. The extracted samples are running with intrinsic jitter of the video clock. The solutions in higher end processors is to use asynchronous resampler in ESS chips. Or have a high performance PLL that cleans up the jitter. None of these are in the cards for this little box.

 

[Stoutblock]

The SACD use case is mainly why these devices are getting attention. At least there’s DOP in this one, but earlier devices only had I2S, so all this jitter would go direct to the DAC chip. Can we speculate about how much this jitter affects DSD streams? In any case using internal SACD DAC strikes me as a much better idea than this device and an uber external DAC.

they make them with just i2s and also with i2s and DoP. Both versions look exactly the same on the outside. The pinout they use for i2s over HDMI is not compatible with my DAC so I just use DoP.

 

[Sonic-Wall]

A much better way to play SACDs is to extract the original DSD64 files and stream them.
There is an extensive thread on how to apply a simple hack to the most common blueray players from Oppo, Sony, Pioneer,…

SACD Ripping using an Oppo or Pioneer? Yes, it's true!

Note: I told the PS3 thread I would announce what I've found, so I am writing this first post, long before I am ready to (i.e I don't have the links ready yet, nor the instructions). I expect my second post to be ready in a few more days. Thanks to some very ingenious folks on other forums around...

audiophilestyle.com

 

[Dennis_FL]

I'm looking for a box to convert HDMI to digital and send it out on ethernet. The latest standard of over-the-air TV (ATSC 3.0) is scrambled and the unscrambler boxes only output in HDMI. My HDHomeRun Flex4 ATSC 3.0 tuner is sitting idle as it can't do anything except for one station.

 

[YSC]

This is a review and detailed measurements of an HDMI to Coax/Toslink and IIs interface converter with support for DoP format. It was kindly drop shipped to me by a member and costs US $103.
View attachment 367609
As you see, there is no brand name on it. Here is a link to the ebay listing: https://www.ebay.com/itm/353354399159

Member wanted me to test its performance while sending DSD data over HDMI but alas, I have no ability to generate such test signals. What you are about to see is its performance while carrying PCM data in the form of J-test signal.

There is facility for external 5 volt input but no supply was provided. So I let it get self powered from HDMI source.

HDMI to IIS/DoP Converter Measurements
Let's start with the dashboard of capturing jitter and its spectrum over Coax output (input is from HDMI):

View attachment 367610

Peak jitter level is 2 nanoseconds. As a way of reference 0.5 nanoseconds is enough to equate the amplitude of the lower order bit in 16 bit content. So this is not good at high level. FFT spectrum shows that majority of that is mains noise at 60 Hz. That jitter will perceptually get masked so it is not very important (indeed, the above measurement has 700 Hz high-pass filter per AES standard). There are also high frequency component around 100 KHz.

Let's compare its performance to that of Topping D10 acting as a bridge between USB and S/PDIF:
View attachment 367613
We see that this HDMI converter has broadband noise that is much higher than Topping. HDMI interface has a lot of jitter since it is made primarily for transmission of video. Without proper clock regeneration it is liable to have such performance issues.

Conclusions
Use this box for convenience of converting one format from another, not for performance reasons.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Is this we can get a hdmi in, then hdmi out for the monitor or tv, but from the box have a splitter for spdif or coax audio out for the hifi dac? I can see this a good use for things like PS5 sending audio through the splitter