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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?

richardbrand

Showing 1 response by fastfreight

fastfreight
916 posts
 

I am surprised no one has mentioned the 5v power typically carried in USB and possible noise introduced as such.  My DAC is optimized for USB, as I use a separated high quality clock connected to the DAC.  Also, I turn off (defeat) the power in the USB output in my Auralic Aries Streamer (a nice feature).  In my old DAC (Tambaqui), AES was the way to go to optimize the output of my Grimm Streamer.  Now, USB without power is  the (recommended) way to optimize my new DAC / Clock.  And clearly in my system, and to my ears, quality cables of either type make a big difference.

Could HDMI have been implemented to achieve both of these results (by the manufacturers)?  Don't know.  But I have used what I think is best for my specific situations. 

Digital discussions are funny.  Perhaps 1's and 0's lead folks to think digitally.  But our hobby is not a yes / no science.  Analogue gear is always discussed in gradients and subtleties, yet digital is often discussed as right or wrong.

Yes I know I did not discuss strengths and weaknesses of HDMI vs USB, only to attempt to discuss how USB can be the best for specific situations.

Happy Easter!

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