HDMI i2s Cable

HDMI is not the same as I2S. You can't use any of those cables ^^^ 

Uhmm, my understanding is i2s with an HDMI port can still use a standard HDMI cable. The i2s interface will not use all the conductors, but it’s just a standard HDMI cable.

An "i2s" specific HDMI cable will have missing conductors for several of the pins, but it still carries the same pin alignment for the remaining.

There is no I2S cable just cables utilized to carry I2S. It can be HDMI cable, ethernet cables even 4 digital coax cables. As long as the pins on the components are set the same a HDMI cable can be used. I’m not sure about the two devices he’s trying to connect if the pins are the same. If they are both set to LVDS then probably any HDMI would work.

I'm so confused 
TUBULUS Argentus website: 
The TUBULUS Argentus i2s cable hdmi is specifically designed for i2s LVDS signal transport and therefor is not suitable as a standard HDMI TV cable.
The TUBULUS Libentus i2s cable V2 is specifically designed for i2s LVDS signal transport and therefor is not suitable as a standard HDMI TV cable.

Phasure Audio Website:

The HDMI^2 is a most robust HDMI cable meant for audio and i2s connections.

Please notice: Although the technical specifications of the cable imply a possible length that exceeds 10m most easily for even 4K video, the possible length for i2s fully depends on the sending device. To this regard it is to be noticed that i2s officially is a chip-to-chip (wire) protocol, meant to be used at very short lengths (think 10cm).

I'm moving to the Matrix because I have a number of DSD128 tracks and can only play them using USB.  When I listen to MQA and everything else using Ethernet via Bridge II, I generally like the Ethernet SQ better. Using a i2s HDMI cable, I'll be able to listen to all of my music through one cable; hopefully, with better SQ.

Once I get the Matrix, I'm going to try one of my existing "quality" HDMI cables just to hear what it sounds like, and go from there.  I only want to buy a i2s cable once, so I'm going to do some more homework, try to audition cables in my system, and then make a buying decision.

I'm not sure of your confusion.  Obviously, you cannot connect an i2s transport to a AV processor.  And you cannot connect a standard AV bluray player to an i2s DAC input.  However, all these devices use the same HDMI cable.  A standard AV HDMI cable can be used on any i2s device, as long as it's connecting an i2s transport to an i2s DAC.

I think you are thinking about the other way.  An HDMI cable that is built specifically and only for i2s DAC cannot be used on a normal bluray / AV receiver because it's missing several of the internal wires.  About 6 of the 19 wires are missing on these special "i2s only" HDMI cables.  (pins 13, 14, 15, 16, 18, 19).

I have spoken to people that have successfully used a normal Wire World Platinum 7 HDMI cable to connect the PS Audio transport and DirectStream DAC.  It works perfectly fine.