thomaspf
1000+ Head-Fier
- Joined
- Aug 30, 2003
- Posts
- 1,220
- Likes
- 70
For some years now we have been discussing the merits of connecting a DAC to a computer via USB. The original USB Audio 1.0 spec was issued almost 10 years ago and it defined 3 different connection models.
The key difference for these connection models is the location of the master clock. Almost all available USB audio devices treat the USB connection very similar to a one directional S/PDIF connection. The master clock for the playback chain is located in the PC and a USB connected DAC needs to estimate the clock from the data stream send to it from the PC.
A lot of engineering IQ has been dedicated to reduce the jitter inherent in such a solution but now you can get a DAC that implements asynchronous USB audio mode.
Wavelength Audio has a new version of their Crimson DACs that operates in async USB audio mode. In this mode the master clock is local to the DAC and a backchannel on the same USB cable is used to slave the data stream from the PC to that clock. Only this connection mode allows you to use a highly stable clock in the DAC to drive the converter directly. As another benefit this works without requiring any additional drivers in Windows or MacOS.
I have no association with Wavelength other than having argued for a long time on this forum and in private that Async mode is the right way to go for high end DACs.
My congratulations for finally making it happen!
Cheers
Thomas
The key difference for these connection models is the location of the master clock. Almost all available USB audio devices treat the USB connection very similar to a one directional S/PDIF connection. The master clock for the playback chain is located in the PC and a USB connected DAC needs to estimate the clock from the data stream send to it from the PC.
A lot of engineering IQ has been dedicated to reduce the jitter inherent in such a solution but now you can get a DAC that implements asynchronous USB audio mode.
Wavelength Audio has a new version of their Crimson DACs that operates in async USB audio mode. In this mode the master clock is local to the DAC and a backchannel on the same USB cable is used to slave the data stream from the PC to that clock. Only this connection mode allows you to use a highly stable clock in the DAC to drive the converter directly. As another benefit this works without requiring any additional drivers in Windows or MacOS.
I have no association with Wavelength other than having argued for a long time on this forum and in private that Async mode is the right way to go for high end DACs.
My congratulations for finally making it happen!
Cheers
Thomas