HDMI DAC

[tdogzthmn]

It seems like USB is the new standard connection for most DAC's but I'm wondering if there advantages with HDMI which would make it better in the long run. Surround sound and high high bit rate support seem nice for those with music that has been mixed in 5.1. I understand there are licensing cost which raise the price of HDMI products but it seems like most DACs ignore HDMI as only being useful for home theater when both audio and video are being played.  Are there any notable DACs that are able to work with more than 2 channels of audio aside from your typical A/V receiver?

[Doc B.]

Look at the Outlaw 975

[John Swenson]

HDMI audio in the "audiophile" world is very tough to do really well. All the mutli-channel formats are encrypted, the specs for these are not readily  available.

In order to use them you need a license (which costs a fair amount of money) and buy off the  shelf chips which implement the decoding. You are at the mercy of the chip you choose to do  it well. As is usual in this business the chips have all been optimized for low cost rather than absolute highest audio quality.

I COULD do it myself in the FPGA but  to get the actual description of the algorithm you have to get a developers license which REALLY costs a lot of money!

USB is a much better way to get multi-channel into an audiophile DAC. The UAC2  spec can handle a LOT of channels (at least 32). I have designed the BH DAC to be able to handle multiple channels from beginning. Sometime in the future I plan on coming up with an add on that will let you connect up to 4 boxes together to make up to an 8 channel DAC. It won't be anytime soon, but I should be able to get it to work.

John S.

[Hank Murrow]

Dear John Swenson;

"Full Member" seems inadequate to describe the contributions you are making to this Forum and the BH community as a whole. While I am largely 'on the Forum sidelines, as my main gig is 'Potter', I certainly follow your posts with pleasure, as I am certain to learn something. I am an early adopter/customer of your DAC, being persuaded by Doc and Paul Birkeland that it will outperform the DAC in my Oppo 95. I eagerly await the Kickstarter campaign underway at present, and also look forward to a BHQuarters visit in August to compare Doc's Oppo with the BH DAC. I will order anyway, but just wish to hear for myself with my choice of music. Please know that one BH fan(my entire amplification system) is excited to be among the first group of purchasers. Thanks for teaching us the fine points of the digital realm, and patiently at that!

Cheers, Hank in Eugene

[tdogzthmn]

Thanks for response John.

It seems like the limitations of USB have yet to be reached even compared to more modern systems like HDMI, or Apple's Thunderbolt.

I'll be interesting to see the BH DAC in an 8 channel config.  4 Boxes in a row seems like a space hog but I'm sure the impressive sound it will produce can quell any complaints!

Currently, I have several DSD and DSD-Master files that hope to be able to play from my iTunes via Audirvana Plus into my A/V receiver over my 5.1 Orca speakers.  I'm trying to untangle all the ways surround sound files can be played from my music library.

Now if only Bottlehead would make a dedicated multichannel amp that works in unison to the multichannel DAC....

 

[Doc B.]

One thing to keep in mind with all of this is that there are several different surround encoding formats, and some of them are only sent over HDMI, like Dolby Digital Plus. That is the one used by Netflix for streaming, and I'm sure some other popular streaming services.

So it might be necessary to find a way to handle getting that HDMI only mutlichannel info into a "USBable" format before it leaves the PC.

[John Swenson]

This is a big quagmire. Most of the modern formats can legally be ONLY decoded in a DAC chip! Movie companies have designed things such that it is essentially impossible to get at the de-crypted audio data in the digital domain, you can't even get a de-cryptor chip, it has to be built into the DAC chip. So if the multi-channel source is in one of those formats there is no way to get it into an external high quality DAC, you are stuck with a DAC that uses one of those DAC chips with the built in decoder.

So if you want to get multi-channel source make sure what format it is in. A multi-channel FLAK works great. But something in multi-channel Dolby.... may be encrypted.  You really have to check with where you are getting the file to find out.

John S.

[tdogzthmn]

My receiver has Coaxial, Optical and HDMI for digital inputs.  But I wasn't sure if the Coaxial can play the DSD and DTS-HD files that I have ripped from blu-ray discs.