As one who has actually done a clock upgrade I can say that it DOES significantly improve the sound of the analog outs. By clock upgrade I mean replacing the two audio crystals that generate clocks that are used to derive the timing for the data going to the DAC chip and the S/PDIF outs (coax and optical). These clocks have nothing to do with the processor clock which is used for such things as ethernet and USB timing.
The internal clocks are somewhere around 35-50 ps, the ones I replaced them with were in the 5ps range. I have some new sub one ps clocks (NOT cheap!) but I haven't gotten around to actually hooking those up yet. Whether this change is going to make a difference to an external S/PDIF input DAC is very dependent on the DAC, and the cable used between them. For some some it will make an improvement and for others it will not. (I don't think it will make anything sound worse!) S/PDIF connections are affected by so many different things that even for DACs that are sensitive to whats going on with the inputs it's essentially impossible to figure out in advance which one will make a difference in a particular setup. It should have NO difference to a USB DAC (of any flavor) since these clocks have nothing to do with with the timing on the USB bus. I don't know of ANYBODY that has tried tweaking the clocks that DO affect the timing on the USB bus. Getting USB DACs to work reliably with the Touch is such a recent occurrence that USB tweaking is very much in it's infancy. I am going to disagree with many around here who think that all USB async DACs are completely immune to anything happening on the computer as long as the data gets transfered correctly. I have tried several and this does not seem to be the case. The async USB method gives the POTENTIAL for high immunity from what's happening in the computer, but it turns out the details of the implementation still make a BIG difference. There are very few manufacturers that are spending the effort to really get it right. So is a clock upgrade a "necessity"? Certainly not. Will it improve things? For the analog outs, yes, for a S/PDIF DAC, maybe, for a USB DAC no. If you have a DAC for which an external reclocker makes a difference, will uprgading the clocks in the Touch do the same thing for less? Maybe. As mentioned before there is far more to a S/PDIF interface than just the jitter of the source, an external reclocker may be affecting one of those other aspects. For example the impedance of the output is just as important as the jitter of the signal, the official spec says outputs and inputs should be 75 ohms, but in reality the impedance of outputs, inputs and cables varies all over the place from 25 ohms to 120 or so. What matters is that they match as closely as possible. So if your DAC has an input of 90 ohms, it doesn't matter if the source has precisely 75 ohms, you will get better results if the source is closer to 90. I have actually seen a case where a reclocker sounded better, even though the jitter on the output was worse than on the input, BUT the output impedance more closely matched that of the input on the DAC. John S. ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=95573 _______________________________________________ Touch mailing list Touch@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/touch
