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Non-standard pinout for i2s via HDMI interface

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Posted on November 19, 2020 at 08:11:18
Duster
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Posts: 16831
Location: Pacific Northwest
Joined: August 25, 2002
It was supersizing to find there is no standard pinout for an i2s interface via HDMI, with some USB to S/PDIF/i2s converters outputting via an HDMI jack with one pinout scheme, while the HDMI input jack of a DAC may involve another pinout scheme. What does one do when the I/Os don't match? I don't know of any different HDMI cables with "mismatched" connectors nor any adapters for the purpose. Must an end user build a custom HDMI cable for the task? TIA

 

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RE: Non-standard pinout for i2s via HDMI interface, posted on November 19, 2020 at 08:54:21
Mel
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At the moment it seems there is no single standard for I2S which seemed to emerge for consumer use in a very unplanned, unintended way. Flexible devices like the ones made by Singxer have dip switches allowing for compatible set-ups. Other devices and some DACs, offer RJ45 cable as an option. They are pretty easy to make up for custom set-ups. Otherwise, as you suppose, a custom HDMI cable has to be made.

 

My DNAFRIPS allows this via a setup menue..., posted on November 19, 2020 at 14:21:56
Ivan303
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Location: Cadiere d'azur FRANCE - Santa Fe, NM
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And there are only a couple differing pin-outs, as I recall.

Audio-GD HDMY may be different from PSAudio, one of the early standards.

Again, I forget as the only Audio-GD DAC I have left uses RJ45 for this purpose.

Generally the Chinese favor one way and maybe PSAudio is different?





 

RE: Non-standard pinout for i2s via HDMI interface, posted on November 19, 2020 at 14:44:47
maxim
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Posts: 426
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Contributor
  Since:
September 24, 2013
I had this problem between CDT and DAC... The CDT producer sent me a converter.

Looked like it was not a big deal producing it. But I am now using AES/EBU interface ...

 

RE: Non-standard pinout for i2s via HDMI interface, posted on November 20, 2020 at 02:18:17
Roseval
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Joined: March 31, 2008
I2S is a protocol designed by Philips in 1986.
Its purpose was to connect a CD player and a DAC over the PCB.
As it was supposed to be used internal, no standard was developed for connecting and external device using a cable.

The Well Tempered Computer

 

Different pinouts for a particular i2s via HDMI cable interface, posted on November 20, 2020 at 15:11:52
Duster
Audiophile

Posts: 16831
Location: Pacific Northwest
Joined: August 25, 2002



The two different pinouts are similar, with some issues of reversed polarity. Perhaps folks can provide comments for the sake of discussion. TIA

 

RE: Different pinouts for a particular i2s via HDMI cable interface, posted on November 21, 2020 at 08:41:23
Mel
Audiophile

Posts: 2435
Location: New York City Area
Joined: February 21, 2001
FWIW my LKS MH-DA004 DAC requires a similar but not exactly the same configuration as the Gustard:

1. I2S_DATA+ / DSD_DATA1+ 2. NC
3. I2S_DATA- / DSD_DATA1- 4. I2S_BCK+ / DSDCLK+
5. NC 6. I2S_BCK- / DSDCLK-
7. I2S_LRCK+ /DSD_DATA2+ 8. NC
9. I2S_LRCK- /DSD_DATA2- 10. NC
11~13. NC
14. DSDOE (=1:DSD Mode 0: PCM Mode )
15~16. NC 17. GND
18. NC 19. GND

I did at one time research a digital bridge that would go from NAS by ethernet directly to my DAC's I2S input and avoid USB entirely, including cable choice. The cable configuration would not have been a problem. But I checked on the performance of what was available at a reasonable price, went a different direction and never looked back. To bridge from USB to I2S requires a high performing unit IMO if you want the SQ that USB is capable of.

 

Often, coax will sound better than external I2S, posted on November 21, 2020 at 09:25:21
Jon L
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Joined: April 6, 2000
because I2S was never meant to be an external digital connection over relatively long distances (vs. board tracing). Also, HDMI connectors or RJ45 connectors used for I2S are often not as optimized for audio as 75 Ohm or AES connectors.

To add to injury, audiophiles often own much higher quality digital cables termianted with 75 or 110 Ohm connectors than the OEM/pedestrian I2S cables.

 

RE: Different pinouts for a particular i2s via HDMI cable interface, posted on November 21, 2020 at 10:29:00
Duster
Audiophile

Posts: 16831
Location: Pacific Northwest
Joined: August 25, 2002



In my case it's more of a curiosity, since I only require 24-bit/48kHz PCM performance-level for streaming audio via ISP broadband cable. The set-up involves S/PDIF via 75 ohm coaxial for one application, and S/PDIF via Toslink for a distributed audio configuration. My extensive digital cable collection from when I used a digital transport to spin Red Book quality discs comes in handy, since I'm able to select the cables that provide the best synergy for both my Gustard DAC-X12 for SS gear, and classic Museatex Melior BS-1 DAC for tube gear.

All things considered, it will be of great interest to find if the Gustard DAC will actually sound better via an AudioQuest Pearl HDMI cable featuring solid core pure copper conductors with foamed polyethylene dielectric vs. my reference-quality solid core pure silver Oyaide FTVS-510 S/PDIF cable with PTFE Teflon dielectric, terminated with pure silver WBT Nextgen WBT-0152 Ag rca connectors. If a separate run for word clock makes that much of a difference for the application, it should be a very telling experience. I reckon my particular application, which is rather modest will not benefit as greatly as a more high-resolution set-up will via an i2s interface.

 

Cut the cable and cross wire it., posted on December 19, 2020 at 12:19:43
gusser
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Posts: 3281
Location: So. California
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Really it's that simple.

I2S is not using HDMI protocol. They audio vendors are simply using a widely supported cable and electrical interface standard to transport the I2S signals. Since I2S between external components needs four balanced pairs, an HDMI cable is ideal. RJ45 Ethernet would work just as well and I think at least one vendor uses RJ45 for I2S.

I2S signals are not running at the extreme data rates as HDMI uncompressed video. The minor impedance mis-match from a DIY splice won't cause any issues. Just try to keep the splice as short as possible.

And of course don't cut up some uber expensive HDMI cable. Any cheap cable will work just fine for I2S.

 

RE: Cut the cable and cross wire it., posted on December 20, 2020 at 02:56:31
Duster
Audiophile

Posts: 16831
Location: Pacific Northwest
Joined: August 25, 2002
Thanks, gusser. You helped clarify the matter, just as I had hoped for.

It's always a joy to explore various cable interfaces that are new to me.

I can now research the notion of an I2S interface properly, with better understanding than before.

Cheers, Duster

 

The original I2S connections were made with DIN5 or 13W3. (NT), posted on December 20, 2020 at 06:41:57
Kal Rubinson
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Location: New York
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