Bryston Outboard DAC

nicolasb · « **Reply #40 on:** 16 Dec 2005, 09:46 am »

Quote from: Mike in NC

Another issue is that although SPDIF may be capable of moving 192/24, most if not all existing DVD-A at that rate limit the resolution of digital information output by the player to 96/24 or below, in some cases to 48/24. My understanding (which, again, may be wrong) is that HDMI includes a form of encryptation and that content providers therefore allow the highest rez signals to be transmitted over it.

Quite correct, yes. There are some proprietary solutions for passing encrypted DVD-A data, such as Meridian's MHR Smartlink, or Pioneer's system (based on Firewire) but it can't be done over SP/DIF.

Jon L · « **Reply #41 on:** 17 Dec 2005, 03:16 am »

<quote>Not all of this is of relevance to a stereo outboard DAC, of course. If it's stereo only, coax SP/DIF probably will provide enough bandwidth, and, if it's a sensible reclocking design, jitter will be less of an issue too. But, in the long term, one would hope that SP/DIF will be phased out entirely in favour of HDMI (or Firewire, but HDMI is more likely). If, ten years from now, you can't buy a transport with an SP/DIF output, you're going to wish that you'd bought a DAC that supports the alternative.<quote>

As much as I wish for a better digital connection for 2-channe redbookl, it's just not going to happen. HDMI has, is, and will always remain predominantly a home theater interface, mainly for video with surround sound thrown in as garnish. No major movie studio will release full-resolution 24/192kHz x 6 channel soundtracks with their movies. I pray every night that DVD-A becomes the next 2-channel standard in its 24/192 glory via one universal high-res digital interface accepted by everybody. Unfortunately, there's good reason I need to pray every night for ThIS pipedream.

Sure, various small niche companies like Muse, MSB, Audio Alchemy have used high-quality digital interface for 2-channel DAC's, but each company had to invent their own proprietary format, not compatible with anyone else. There's NO reason to hold hope that any 2-channel redbook digital interface better than spdif will ever be developed now or ever that will be universally adapted as de facto standard.

So as much as I hate Sony and Philips engineers who condemned us to the stupid SPDIF (Sony Philips Digital Interface), that's what we are and will always be stuck with for 2-channel digital interface. Might as well try to make the best of it.

nicolasb · « **Reply #42 on:** 19 Dec 2005, 10:43 am »

Quote

So as much as I hate Sony and Philips engineers who condemned us to the stupid SPDIF (Sony Philips Digital Interface), that's what we are and will always be stuck with for 2-channel digital interface. Might as well try to make the best of it.

If someone is using an outboard DAC, there's no reason to assume that they will be using a dedicated CD transport to drive it. On the contrary, in fact: if it's a decent reclocking DAC you'd be crazy to use a dedicated CD transport. Instead you'd use your DVD/HD-DVD/BluRay player. If that player is capable of outputing digital audio over HDMI (particularly asynchronously over HDMI) it would be a shame if the DAC were not able to take full advantage of it, even if 16/44.1 is the best source you get.

James Tanner · « **Reply #43 on:** 19 Dec 2005, 05:53 pm »

Hi Thomaspf,

Can you direct me to sources for more information on asynchronous USB audio protocol as you mentioned in your earlier post?

james

Mike-48 · « **Reply #44 on:** 20 Dec 2005, 12:19 am »

Quote from: nicolasb

If someone is using an outboard DAC, there's no reason to assume that they will be using a dedicated CD transport to drive it. [...] you'd use your DVD/HD-DVD/BluRay player. If that player is capable of outputing digital audio over HDMI (particularly asynchronously over HDMI) it would be a shame if the DAC were not able to take full advantage of it, even if 16/44.1 is the best source you get.

Yes, I agree with that, and that's most of what I was trying to say. Even the less expensive players these days have HDMI out, as so expensive units like the Meridians. That HDMI also carries video is irrelevant -- it is currently the best standard digital audio link available. It can also provide a path to adding a multichannel option or upgrade to the DAC. I can't understand why anyone would develop a new DAC today without HDMI input.

thomaspf · « **Reply #45 on:** 20 Dec 2005, 05:05 am »

Hi James,

yes of course. This is explained in detail in the old USB audio specs. The newer 2.0 specs do not go into sufficient detail.

http://www.usb.org/developers/devclass_docs/audio10.pdf

I could call you and walk you through the details. Windows Vista will ship with improved asynchronous USB audio support. Send me mail if you want to talk.

Cheers

Thomas

thomaspf · « **Reply #46 on:** 20 Dec 2005, 05:18 pm »

Hi nicolasb,

I did not think there is such a thing as asynchronous audio over HDMI?

Do you have a pointer?

Cheers

Thomas

PavelL · « **Reply #47 on:** 30 Dec 2005, 06:39 pm »

I'm REALLY SURPRISED!!! Only once in this whole thread I-LINK was mentioned!!! It carries both SACD and DVD-A as well as PCM! No jitter issue with i-link. Even mass-market products like Yamaha 4600 & Z9 have it, I believe it is a MUST-HAVE feature. I myself am very happy with it! No fancy cabling needed.

thomaspf · « **Reply #48 on:** 30 Dec 2005, 07:00 pm »

And why would there be no jitter issue with 1394 audio?

Unless both devices implement the flow control extensions which not many do you are stuck with an isochronous transport. By the very nature of this transmision technology you have more jitter in the stream. The receiver still needs to follow the clock of the sender and will have to use some form of PLL to recreate a local clock base.

HDMI is worse since there is no back channel and less hope of an asynchronous mode like in USB and 1394.

Cheers

Thomas

Mike-48 · « **Reply #49 on:** 1 Jan 2006, 05:18 pm »

This is sad to hear -- that after 20+ years of digital audio, we still have no standard, jitter-resistant, high-definition digital link.

Andrew B. · « **Reply #50 on:** 10 Jan 2006, 10:51 pm »

Quote from: kfr01

I'd also pay twice the price for something 50% better from a solid company like Bryston.

The challenge is actually making it perform 50% better. From what I've read the Benchmark measures pfg for most practical purposes.

I think your other "not to like" input is right on, however. And implementing these changes alone -might- make it 50% better. Especially the high quality remote control stepped attenuator. Save me having to buy a remote control passive pre, and I'm sold.

You couldn't even make it 5% better on any objective measurement.

More importantly, the Benchmark sounds better than any CD player or DAC I've ever owned or heard - and I sold a $12,000 Naim CD player to buy it, having listened to Meridian, Chord etc. It is a remarkable piece of gear which makes life tough for anyone else coming into the market.

Andrew