Please Help!! looking to get into computer audio.

@sun-warrior "So isolation has nothing to do with choosing computer or NAS as server."  

I see your point, but for the benefit of others, let's clarify that if your attach either 1) a computer and any attached hard drives or 2) a NAS to a router(usually in a different room on a different electrical circuit!) thus isolating the device from the DAC you've still got to get the signal to the DAC by ethernet, wifi or a power line adapter solution.
For my money, that's where the microRendu does a superior job vs. anything me and many others have heard.

For those who prefer to keep the PC or Mac located in the listening room, receive the music from on that computer and connect directly to the dac, they are in some ways fighting an uphill struggle regardless of which cable type or USB/SPDIF adapter they use.  Cheers,
Spencer

eric - I fully understand async USB and jitter. However, if the DAC resamples using its own clock, then async vs. sync timing should not be an issue. The DAC controls the final timing, and it is independent of the usb timing. If some people think that DAC sounds better with S/PDIF than USB that is fine. But the issue is probably not jitter in the USB signal, since the DAC reclocks the signal anyway.

My point was simply that the OP should try the USB from his laptop to his DAC before investing in lots of other options.

Um, no you dont, but im not intersted in the argument. 

erik - This is probably not the place for this discussion, but here goes anyway. You have  to understand that the DAC completely reclocks the signal using its own internal clock. The DAC receives the data from its usb input, puts the data into an internal buffer and then pulls the information from its internal buffer and, using its internal clock, reclocks the signal. That was done by Brystron to avoid jitter problems on the USB.

Please explain how the sync timing on the USB effects the internal reclocking of the signal. The only way it can is if the sync usb cannot fill the buffer fast enough, which is very unlikely.

The reclocking process is not done by all DACs. Many just use the timing that comes through the USB, in which case async is certainly preferable to sync USB. But, since the Bryston DAC uses its internal clock to reclock the signal, the jitter on the usb does not make its way into the final data.

You might want to read the Stereophile review, in which they clearly state that the BDA-1 reclocks the signal internally, in order to control jitter.

http://www.stereophile.com/digitalprocessors/bryston_bda-1_da_converter/

From the review

" One of Bryston's primary goals for the BDA-1 was to reduce clock jitter, ie, mistimings of the digital datastream presented to the DAC. Unlike the company's BCD-1 CD player, a one-box transport and DAC, the standalone BDA-1 must reclock all signals fed to its data inputs"


As an aside, I used to make my living doing realtime programming on realtime operating systems. The issue of timing incoming signals coming into a computer is well known to me.

To make some terms more clear, and take them out of vendor-speak we are talking about the differences between Asynchronous USB (A-USB) and Asynchronous Sample Rate Conversion (ASRC).  Usually vendors will call ASRC something like upsampling and re-clocking or something like that.  The Wyred4Sound Remedy Recklocker is an example, but many DAC's have this feature built in. 

Both help to reduce jitter but the similarities in how they work and how well they may work in any given circumstance are not the same. Jitter from an A-USB source is often as low as the DAC that is pulling the data, and is bit-perfect.  That is, the DAC receives exactly the bits in the source file, and the output signal is evidence of the very best the DAC can do. There's very little to do to make a no-compromise solution with this interface. 

As you are expecting, ASRC will also improve bad sources, reducing measured jitter somewhat but at a certain point, based on it's implementation, it has to give up. This can be improved upon by bigger input buffers, but it usually does not yield the same level of improvement, especially with things like internet radio, iTunes, Chromecast, etc.  The worse the input signal (i.e. more jittery) the worse the output signal. By contrast, A-USB can tolerate a lot of lag in the input before ANY of it becomes measurable.  Further, ASRC is not bit-perfect.  The entire output signal is a mathematical reconstruction of the input. For fun reading on this look up some of the writing around the closed-form digital filters used by Schiit. Of course, they are all pro-Schiit, but they offer a great education in how ASRC is accomplished, and what kind of compromises are made.  In general, ASRC prefers time precision to bit-perfection. It will sacrifice the data to meet it's time goal, as much as it can. 

Of course, the devil is in the details, and anyone can make a crappy version of any technology.  You can also chain one after the other, yielding very good results at times.

A better option, in my mind, is the latter Bryston DAC's with built in USB 2.0 A-USB support AND upsampling.  Given the option for just 1, I'd take A-USB any day of the week. 

Best,

Erik