DAC gives me the jitters

(2) Differences should be minimized but not eliminated. There's still noise and bandwidth. I suspect that reflections in cables can appear as noise also so thats not out of the equation either. I don't know how much bandwidth (both cable and device) will effect things but oversampling a square should do better than a sine unless you're interpolating back down to a lower (over)sample rate which would have it's own set of issues. Of course, since it's becoming sinewaves anyway, bandwidth limitations should mostly average to about where things should be anyways but differences may always be present. Jitter free doesn't mean perfect as long as the bits show up. Just better and closer than in the past. No free lunches but hopefully gourmet food at corner restaurant prices.

According to the manual there is a Sync light which "illuminates to indicate that the DAC’s internal clock is precisely synchronised with the input data stream".

If that light comes on it is hard to understand how there would be a problem with jitter.

It would certainly be interesting to know whether sources such as a Logitech Squeezebox or an Apple Airport Express have sufficiently good digital outputs to keep the Sync light on.

Which leaves noise - again, hopefully the DAC is competently screened, so I would hope that noise isn't an issue, presuming you use optical interconnects.

I can't understand much of js' post.

Manual

At one of the demos I attended I was told that the DAC is still vulnerable to very high frequency noise despite their best efforts to isolate it. This was the reason given for USB sources sounding worse than SPDIF, as the USB protocol has much higher frequency components.

@ DaveBk:

What about a USB memory stick which is rather a "passive" USB source?

Thanks

We did not discuss it directly as the conversaton was more about using USB to directly interface between a computer and the DAC. With the DAC acting as the host reading content on a memory stick I suppose Naim have some opportunity to manage the protocol by for example selecting one of the lower transfer rates?

I suspect they meant more noise rather than higher in freq. I suspect USB could transfer noise that's higher in freq and perhaps that's where most of it exsists but any noise would be undesirable. Usb transfer rate on a stick would more than likely be limited by the stick in use.

On the basis that most gardeners define a weed as being any plant that's growing in the wrong place, I presume an electronics engineer could define noise as any signal that's superimposed on the signal you are trying to process.

As USB2 can transfer at up to 480Mbit which much higher than the 2.8Mbit a SPDIF link with CD quality data handles, it represents a much higher frequency signal source in the case. If this gets superimposed through RF coupling to any of the other signals being processed it could have some impact. Given the lengths Naim have gone to in the design to isolate DSP noise from the analogue sections I suspect they would prefer to keep USB noise as low (both frequency and amplitude) as possible.