Is a USB audio DAC interface needed just for DSD streams?

[GUTB]

There's 2 benefits to USB: high bandwidth and asynchronous communication, which just means the DAC's better clock can take control of the USB communication resulting in reduced jitter. The choice between USB and SPDIF comes down to 2 factors:

 

1. Are you going to do high-rate DSD up-sampling and your DAC/interface's SPDIF interface can't support the required DoP bandwidth?

If YES than you have to use USB. If NO, move on to...

2. Do you have a high quality modern DAC that can clean up SPDIF jitter?

If YES than you can use SPDIF. If NO you should use USB -- although, chances are if it's not a modern high quality DAC its USB quality is probably going to suck anyway!

 

Additionally, there is a HUGE caveat when it comes to USB -- you must make some effort to feed your DAC a clean USB signal. There will be a large sonic degradation if you feed a DAC dirty USB lines from an unconditioned / high-noise source.

 

 

[GUTB]

1 hour ago, WuNgUn said:

So an audio Grade, USB adapter with a high grade clock and external power is basically a must...? And a boutique USB cable, of course.... 

 

Not a must. An audiophile-grade USB controller does help, but the improvement is relatively minor. But you do have to provide a clean 5V line to the DAC. A motherboard featuring audio-quality USB ports (older MSI and current Gigabyte gaming motherboards offer this feature), an iGalvanic works, other conditioners / re-clockers work at varying degrees of quality.

 

I haven't tested high end USB cables yet so I can't comment on their effectiveness on SQ.