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Why does USB feature so much in discussions about DACs when the newer HDMI seems better?

I am a bit confused about the frequent mention of USB in the context of stand-alone Digital to Analog Converters (DAC).  Why is HDMI left out?  Is this a US versus Europe / Asia thing?

The Universal Serial Bus (USB) was introduced in 1996 by a group of computer manufacturers primarily to support plug-and-play for peripherals like keyboards and printers.  It has only two signal wires, plus two wires that can supply DC power.

The High-Definition Multimedia Interface (HDMI) was specifically designed by a group of television manufacturers for transmitting digital audio and video in many formats.  It hit the shops around 2004.  There are 19 pins supporting four shielded twisted pairs, and seven other wires (3 of which can instead form a shielded twisted pair for Ethernet).

I have three universal disk players from Sony, Panasonic and Reavon, which all have two HDMI outputs, one can be dedicated to audio only, the other carries video or video plus audio.  (Only the Panasonic does not support SACD).  My Marantz AV 8802 pre-processor has 11 HDMI connections and only two USBs.

Of course, both USB and HDMI continue to evolve.  Then there is the Media-Oriented System Transport (MOST) bus designed by the automotive industry, which looks even better.

Why is it so?

128x128richardbrand

Showing 2 responses by vthokie83

vthokie83
965 posts
 

SNS

You've nailed it perfectly. There are SO many reasons to use I2S if you can, and you explained it really well. I agree that short HDMI cables are best, but I've had excellent results with the Audioquest Vodka 48 8k/10k cable at 1 meter. For small budgets, the Supra 2.1 HDMI works really well as does the Audioquest Cinammon HDMI.....but those needed to be shorter than 1 meter for best results

It is true that there is no standard for I2S pinouts, but I've never had a problem with Supra or Audioquest. Also many DACS provide pinout configuration, I know that Denafrips does in all of their DACS.

The other benefits can be true of DDCs too, as it allows for: better quality clocks, galvanic isolation, optical isolation, separating the data and clock signals, and of course keeping the I2S signal in tact from the DDC through the DAC.....with no further conversion until the Digital to analog conversion in the DAC

vthokie83
965 posts
 

richardbrand

That's true, I did not....and I do understand your point. I'm not an electrical engineer (I'm mechanical) nor a builder of audiophile equipment. I was responding to the various USB/I2S/SPDIF/Toslink posts in between, and reflecting on my own personal experience with my system

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