Get an asynchronous DAC and stop worrying about jitter!
You are talking about using USB. Transports do not connect with USB. Even with USB, you are at the mercy of the jitter in the USB module in the DAC. This varies widely. Even with USB, you have SQ issues due to signal integrity on the USB cable and common-mode noise. Both of these introduce jitter into the USB interface.
I have heard and liked the CEC beltdrive transports
I have modded these in the past. Reclocking is better.
What must be realized by everyone is that there is no panacea, no silver bullet. Even reclockers are somewhat sensitive to incoming jitter, although much less than other devices.
If you do get a DAC with a USB or Ethernet interface in it, you are stuck with the jitter of that master clock and supporting circuitry/power subsystem. In general, the more you spend, the better the SQ with these, however many companies outsource these interfaces, so they don't have control over the design and don't understand the design. They cannot easily make improvements over time.
A company like Empirical Audio that does not outsource the design can make improvements over time to reduce jitter. We have made mods to our interfaces many times. Our Ethernet and USB interfaces now deliver S/PDIF signal with 10psec of jitter, directly measured at the end of a 4 foot BNC coax. Same with I2S. The only advantage of these interfaces over a reclocker on S/PDIF is that they support native hi-res up to 24/192. This advantage is not usually even audible in most systems. If 44.1 signal has really low jitter and the DAC has a decent digital filter (or none), the advantage of 24/96 and 24/192 is much less. This makes it much more enjoyable to listen to classic rock and jazz etc..
Steve N.
Empirical Audio
