Study: Is I²S interface better for DACs than S/PDIF or USB?

[Roland68]

I²S was originally intended for on-the-PCB digital transport over PCB traces with carefully designed impedances to avoid pulse relections. Using it through a cable seems a dicey proposition at best.

This statement is based on what?
Because LVDS was developed precisely for such applications. If LVDS had been around 10-15 years earlier, Sony and Philips might not have developed SPDIF at all.

LVDS works very well everywhere, in our monitors, computers, notebooks, televisions and no one notices. But also everywhere in the world in data transmission, data storage, machines and production control, etc. It is one of the most widespread industrial standards worldwide and the standard when it comes to transmitting inter IC connections over short cable routes without loss and without interference.

 

[voodooless]

Been there done that:

Sabaj A30a announced

I disagree, the scheme in A2 is a simplification of processing for marketing purposes. We can speculate what we want... Right... So we need A2 pictures to confirm )) We now that VMV is the higher-end brand in SMSL lineup. The A2 is more expensive because of the design and the VMV tag

www.audiosciencereview.com

 

[Hernandezt]

No. HDMI and I2S are completely different standards. They just happen to use the same connector.

Just use the coax digital ouput. As you can see from the first post in this thread, sound quality will be identical.

Thanks a lot for your reply, I see, yes I am currently using the coaxial connection to connect to the DAC, it's just because that DAC has only one coax input and I am using also a streamer with the coaxial, so I have to switch cable all the times, for that I was thinking about that I2S.
Thanks again

 

[voodooless]

HDMI and I2S are completely different standards. They just happen to use the same connector.

No they don’t. There is no official standard for I2S over the HDMI physical interface. It’s just something the audiophile industry shoehorned in top of I2S so they can feel special and have another nonsense feature to sell.

 

[antcollinet]

Arguably a data stream with an embedded clock (such as Manchester encoding) would in theory be more foolproof.

However everything depends on implementation regardless of the digital transport mechanism.

I²S was originally intended for on-the-PCB digital transport over PCB traces with carefully designed impedances to avoid pulse relections. Using it through a cable seems a dicey proposition at best.

You're replying to a post from 4 1/2 years ago.

 

[antcollinet]

Thanks a lot for your reply, I see, yes I am currently using the coaxial connection to connect to the DAC, it's just because that DAC has only one coax input and I am using also a streamer with the coaxial, so I have to switch cable all the times, for that I was thinking about that I2S.
Thanks again

Ok - as an alternative. Coax to Toxlink converters are inexpensive. You could then use the Toslink input to the DAC.

https://www.amazon.com/s?k=coax+to+toslink+converter&ref=nb_sb_noss

 

[antcollinet]

No they don’t. There is no official standard for I2S over the HDMI physical interface. It’s just something the audiophile industry shoehorned in top of I2S so they can feel special and have another nonsense feature to sell.

Feel free to replace my word "standard" with the word "interface" It's what I meant anyway.

 

[Hernandezt]

Ok - as an alternative. Coax to Toxlink converters are inexpensive. You could then use the Toslink input to the DAC.

https://www.amazon.com/s?k=coax+to+toslink+converter&ref=nb_sb_noss

Thanks for the suggestions, will think about that, also because actually the streamer I am using has also the optical connection..., so I could use that one directly, and let the coaxial dedicated to the blu-ray, I am a little concerned about using the optical on the streamer... I know should be the same... just I need to change my mind, my previous DAC had 2 coaxial input

 

[voodooless]

Feel free to replace my word "standard" with the word "interface" It's what I meant anyway.

The first sentence is fine. The problem is the second one

 

[antcollinet]

Thanks for the suggestions, will think about that, also because actually the streamer I am using has also the optical connection..., so I could use that one directly, and let the coaxial dedicated to the blu-ray, I am a little concerned about using the optical on the streamer... I know should be the same... just I need to change my mind, my previous DAC had 2 coaxial input

Coax and Toslink are about as identical as it is possible to get. Literally the same bits using the same protocol.

Toslink has the added benefit of galvanic isolation - so elimination of one path for ground loops.

 

[antcollinet]

The first sentence is fine. The problem is the second one

Are you telling me there aren't devices using HDMI connectors for I2S?

 

[voodooless]

Are you telling me there aren't devices using HDMI connectors for I2S?

Yes! It’s not I2S, it’s FrankenI2S. I2S does not define connectors, because it’s just PCB traces going from one IC to another.

 

[antcollinet]

Yes! It’s not I2S, it’s FrankenI2S. I2S does not define connectors, because it’s just PCB traces going from one IC to another.

Right - so in the context of answering the question asked my statement was perfectly valid.

The FrankenI2S has - by use of HDMI interconnect - confused the questioner. My answer was - I believe - correctly worded to eliminate that confusion.

If you want to gripe about the misuse of the I2S interface as a fundamental issue : take it up with someone who gives a damn.

 

[voodooless]

If you want to gripe about the misuse of the I2S interface as a fundamental issue : take it up with someone who gives a damn.

I’m way ahead of you :

How to make i2s port in smsl do200 mkii work.

I am trying to audio from insigna firetv through hdmi (arc) port to smsl do200 mkii i2s port, the dac say no signal. i configured tv audio out to hdmi arc or toslink optical. HDMI cable is the only cable available at the moment. i set to PCM, Dolby, or Auto to no success. is there any...

www.audiosciencereview.com

Clearly plenty of people care.

Fundamentally, I’m not necessarily against extending the I2S standard with an LVDS spec and physical interface for inter-device audio communication. But it must not use an existing connector that is already part of some other communications standard. That’s just confusing. And let’s just have one standard, not at least 4 different ones using the same connector

 

[sailor2005]

Could maybe someone just quickly explain me if the i2s port of my dac smsl do400 is compatible with the Sony UBP-X800M2 using its hdmi output dedicated for audio?

As it is, the answer is no BUT with something like this, you can

HDMI/MHL Digital Interface Audio I2S/DSD/Optical/Coaxial HDMI To I2S IIS DOP ts | eBay

Support coaxial DOP board. When DSD input, I2S port outputs DSD, coaxial output DOP64, it is used with a decoder supporting DOP. HDMI/MHL Digital Interface Audio I2S/DSD/Optical/Coaxial HDMI To I2S IIS Support Coaxial DOP Board.

www.ebay.com

It takes the HDMI signal and extracts the audio from it. If it is DSD you can send it to the DO400 as I2S or as DoP (DSD64) thru SPDIF (coax or Toslink). I have the DO400 too. I use an older Sony BDP-S370 to send DSD thru I2S. A friend of mine has the same box and the Sony X800M2. In his case he uses DoP thru Toslink to a Denafrips Ares 2. The Ares shows it is receiving DSD.

 

[Philbo King]

You're replying to a post from 4 1/2 years ago.

Yeah - didn't see it till today.

 

[Hernandezt]

As it is, the answer is no BUT with something like this, you can

HDMI/MHL Digital Interface Audio I2S/DSD/Optical/Coaxial HDMI To I2S IIS DOP ts | eBay

Support coaxial DOP board. When DSD input, I2S port outputs DSD, coaxial output DOP64, it is used with a decoder supporting DOP. HDMI/MHL Digital Interface Audio I2S/DSD/Optical/Coaxial HDMI To I2S IIS Support Coaxial DOP Board.

www.ebay.com

It takes the HDMI signal and extracts the audio from it. If it is DSD you can send it to the DO400 as I2S or as DoP (DSD64) thru SPDIF (coax or Toslink). I have the DO400 too. I use an older Sony BDP-S370 to send DSD thru I2S. A friend of mine has the same box and the Sony X800M2. In his case he uses DoP thru Toslink to a Denafrips Ares 2. The Ares shows it is receiving DSD.

Thanks a lot for your hints, will for sure have a look at this device, by the way, I am using the blu-ray Sony actually mostly for watching concerts

 

[srkbear]

No they don’t. There is no official standard for I2S over the HDMI physical interface. It’s just something the audiophile industry shoehorned in top of I2S so they can feel special and have another nonsense feature to sell.

By “audiophile industry” you mean PS Audio, who railroaded I2S into the gullible minds of consumers everywhere as the “superior” digital connector, only so they could complete the circle of their Perfectwave SACD transport shill. Paul only started espousing this myth after he released the first incarnation of this player, the Direct Stream SACD transport, which accomplished the same juggernaut—it’s literally the only player that will output the native DSD signal to an external DAC, via an I2S connection, of course.

They even admit as much on their website—that the way they managed to accomplish this previously inscrutable task of circumventing Sony’s DRM restrictions (which mandated that all players downsample SACD discs to 48Khz/16 bit by their S/PDIF output transmitters) was to utilize an I2S connection. That is the entire origin of this fable that I2S “sounds” better, and you better believe that owners of those PS Audio players will fight you to the death if you challenge this.

 

[asrUser]

Is the optical input better than USB in terms of Galvanic isolation? Though I would need an additional DAC just for the optical output, because my PC got no optical output.

 

[somebodyelse]

Is the optical input better than USB in terms of Galvanic isolation? Though I would need an additional DAC just for the optical output, because my PC got no optical output.

Yes - normally USB has no galvanic isolation. Coax digital is sometimes transformer isolated at the sending end.

You can buy USB isolators, but there are some limitations to be aware of. Some sold for HiFi aren't really isolators, disconnecting the ground and/or 5V lines after some delay. This may work for some things, but doesn't comply with the USB specifications and may cause devices not to work in interesting ways. Proper USB isolators can be inexpensive (see adum3160 based isolators), but those tend to be limited to lower USB speeds (12Mbps).

Some motherboards have a pin header for spdif output (optical and/or coax, depending on the output adapter). If you don't have that there are inexpensive USB to toslink options like the Hifime UT23 doing up to 24 bit 96 kHz.