"So, OK it is plausible that different USB cables sound different from one another."
If there are any measurable "speed" differences in cables that would cause timing issues the difference would probably so small compared to any clocking on the host or re-clocking in an adaptive USB based DAC. With an synchronous DAC it wouldn't matter with all other things being equal (clocking into DAC chip, etc.).
And, then even if there is measurable jitter for whatever reason, how much jitter is needed for it to be audible using strict ABX testing? Not the single person swapping cables and thinking what they recall hearing minutes ago is accurate.
If there are any measurable "speed" differences in cables that would cause timing issues the difference would probably so small compared to any clocking on the host or re-clocking in an adaptive USB based DAC. With an synchronous DAC it wouldn't matter with all other things being equal (clocking into DAC chip, etc.).
And, then even if there is measurable jitter for whatever reason, how much jitter is needed for it to be audible using strict ABX testing? Not the single person swapping cables and thinking what they recall hearing minutes ago is accurate.