Hello Steve,
I would really appreciate if you could give any specs about how much jitter Emp.Audio devices have (Pace-Car, Off-Ramp or Freeway 2). I do not understand how it can be that these devices where built and are sold as having ultra low-jitter but there is not a single word about how much jitter they have.
I read the Freeway 2 has a "low-jitter SMD monolithic clock instead of a Superclock (as used in the Off-Ramp)". But what's the effect of that? More jitter? How much more?
I dont currently have equipment that will characterize jitter this low. It's beyond the capability of my test equipment. Expensive equipment is required, and at this point I need to put that money into launching my products, which includes outsourcing the board assembly. This way I can reduce my backlog and lead-time. My customers would rather I do this than some measurements.
For the Pace-Car I see there are four available clocks. But what's the difference between them? Is the Superclock 4 the best? Is it the same as the Superclock used in the Off-Ramp or another one?
The Standard clock has low-jitter (<2psec RMS jitter), but the Superclock4 (< 2psec RMS jitter also) is deifinitely more musical. The Ultraclock is more detailed than either of the others and lower jitter (not specified), but maybe not as musical as the Superclock4. The Spectra as well as the amplitude plays a big part in the audibility of these clocks as indicated by the specs, which are a bit meaningless after you get to this level. You have to listen to music with the clock to hear the difference. It's all about audibility, not measurements, and this has not been adequately characterized. For instance, the AES test reports showed that jitter below about 20 nsec was not audible. This is 10,000 times more jitter than these clocks. I dont recommend that you base your buying decision on measurements. It's how it sounds that matters.
http://www.audiocominternational.com/product_detail.asp?id=8http://www.audiocominternational.com/product_detail.asp?id=27I like what I read about the Pace-Car, but having to send you the device it's going to work with is not an option (can be so many things, change over time...). Is there no way to design the Pace-Car so it avoids this "tuning" - so it works with any source?
I have a mode planned for the Pace-Car 3 which will work with all devices (but will not be bit-perfect), but in the meantime it can work with all of these without tuning:
Sonos, Squeezebox3, Duet, Olive, Transporter, Lynx AES16 and other PCI cards with word-clock input, transports with word-clock input, such as the Marantz just reviewed in Stereophile.
There is no sonic degradation with choosing any of these, either wired or WiFi. They are all identical.
BTW, a reviewer with the right equipment did make some measuements on my older Off-Ramp Turbo 2, which has more jitter than the Pace-Car. His findings were that the distortion due to jitter in the analog waveform was in the noise level of the Audio Precision measurement gear. If he cannot measure the jitter of my old Off-Ramp turbo 2, how in the world can he measure the Pace-Car 2
Steve N.
