So, I went to the Stereophile archives to look for JA's DAC measurements. I found some very interesting things. First, both the Squeezebox and Transporter perform very well compared to even the best gear, in terms of p-p jitter. The Squeezebox is around 300 ps, while the Transporter is around 200 or so. Interestingly, the dCS Verona Master Clock clocks in with a jitter measurement slightly higher than the Squeezebox. Also, JA found that with the Nagra DAC (supposedly a "modern" DAC that rejects jitter):
> Driving the Nagra DAC with S/PDIF data from a PS Audio Lambda CD > transport gave a measured jitter level of just 140 picoseconds > peak-peak, which is superbly low. with almost all of that jitter > data-related (red numeric markers). Changing the data source to my PC > playing a WAV file and connected via a TosLink cable increased the > jitter level to 333ps, with the increase due to low-frequency sidebands > (not shown). While this is still very low in absolute terms, the > difference between its electrical and optical performance suggests that > the Nagra is not totally immune to data interface issues. Compare that with a claim from the Nagra website (my bold): > The DAC features an ATF (Adaptive Time Filtering) module that increases > the quality of all signals just before the conversion stage by > *eliminating the jitter*. I didn't read whether JA heard any difference between the two interfaces, but it does show that simply the difference b/w two interfaces (well a different transport, too) on even a very high-end DAC can produce very different levels of jitter. It also makes one question the marketing claims. -- ezkcdude There are 10 kind of people in the world - those who understand binary and those who don't. SHINYMETAL '*Site*' (http://www.ezdiyaudio.com)| '*RSS*' (http://www2.kumc.edu/students/ezamir/rss/ezdiyaudio.xml) |'*Forum*' (http://ezdiyaudio.informe.com) ------------------------------------------------------------------------ ezkcdude's Profile: http://forums.slimdevices.com/member.php?userid=2545 View this thread: http://forums.slimdevices.com/showthread.php?t=38637 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
