Why do digital cables sound different?

I'm still missing something, but I've been known to be dense before - my take on timing errors would be that they cause bits to be misinterpreted - since sender and receiver have subtly different experiences with their independent clocking mechanisms, the receiver interprets things slightly askew and gets a different "answer" than the sender sent. The result would be different bits fed into the DAC than if there was a perfect transfer. Is there something to "timing errors" beyond this that I'm missing?

Now you have got me Kthomas - I don't know, and have not done much work on it since I cannot change how DACs work. I have only got so far as observing how transmission interfaces are subject to jitter and how jitter results in harmonic distortion. I suspect you are not quite right about the DAC getting bits wrong and it is more about how the DAC converts the digits to an analogue wave-form and how this is upset by timimg errors in the arrival of the digits. I surmise that the DAC cannot construct an accurate analogue waveform from a datastream containing jitter errors without a perfect buffering system. One can imagine how with no buffering at all, a DAC would find it difficult to create a perfect analogue waveform with digits arriving with imperfect timing. When I add to this the fact that I have never heard a buffering system that eliminates upstream jitter (they just reduce it or change it), then I can intuitively imagine how the problem arises. If I understood more about how buffering systems fail to work perfectly then I might have a better answer.

Redkiwi, I am not a designer of digital audio playback devices but I thought that the data sent to the DAC is asynchronis. If that is true where are the timing errors? Is the data clocked from the transport to the DAC or is it really asynchronis? I do not know, but if it is asynch, then the statement about arriving with perfect timing does not make sense to me. Is it the timing between bits that you are talking about? If that is the case, how can the cable change the timing between the bits or even cause jitter?

Redkiwi, even if jitter did cause a problem, I do not think it would manifest itself in harmonically related distortions. I can't see it causeing either higher or lower order distortions.