Several of us are using the new Auralic Vega DAC with a Femto Clock. This extremely accurate clock has 4 settings with the EXACT setting being the tightest setting, but unforgiving with timing issues coming from the source component. If the source component cannot supply a sufficiently accurate clock signal one needs to come out of EXACT mode until sync is achieved, however this reduces the sound quality that is available on the EXACT setting of the Femto Clock.
When playing DSD and DSD128 files on JRiver for Mac, one can switch tracks with no issues as long as one only plays DSD or DSD128 tracks. If one is playing a 16/44 CD track and then selects a DSD or DSD128 track a serious issue occurs about 20% of the time. A very loud waterfall sound develops that usually goes away in 3 or 4 seconds.
On my system the noise is not so loud that I fear for my speakers but another user mentioned on the Computer Audiophile site that he may have damaged one of his tweeters. The designer of the Auralic Vega DAC says that this noise occurs when the Femto clock is on the EXACT setting and the source component (Mac running JRiver for Mac) is sending a clock signal that is of lower quality than is compatible with the Femto Clock on EXACT setting.
One solution is to set the clock on a lower than EXACT setting, but that compromises the sound quality available with the EXACT setting.
Since the noise ONLY occurs in the situation mentioned above, and then cures itself, I believe this may be an issue with JRiver for Mac. On the other hand, it may be an issue that cannot be solved, and then will become something that everyone with a DAC with a Femto Clock will have to deal with. So until this issue is resolved PLEASE TURN DOWN THE VOLUME WHEN SWITCHING FROM CD TO DSD OR DSD128 TRACKS ON JRiver FOR MAC.
David Levinson
Senior Vice President of the Los Angeles and Orange County Audio Society
Newport Beach, CA.
david52 at pacbell.net
