USB from external hard drive to mac mini

I vaguely understand why the quality of USB cables carrying an actual digital audio signal can effect the quality of sound. Something to do with timing and jitter and waveforms. But I swear that I can hear a difference between USB cables running from my external hard drive to my computer. This doesn't make sense to me because the data is in blocks and there is no timing issue.

Has anyone else heard a difference between USB cables used in this application, or am I hallucinating again?
The one effect that I can envision possibly being relevant is that the quality of the shielding in the cable will affect how much rfi/emi (radio frequency interference/electromagnetic interference) is radiated from the cable, which might be picked up by and affect circuits in the dac or elsewhere in the audio system.

Obviously the likelihood of that being a significant effect would depend on the proximity of the computer and the hdd to the dac and the audio system.

So you may not be hallucinating! :)

-- Al

We, the audiophiles have a tendency of hearing what we want to hear.
I noticed it too. There's also a noticeable difference plugging the external hard drive into a conditioner as was the case with a Hydra-6 that I own. Enough to where it tips the balance too much in the upper frequencies and I avoid it. I picked up a USB mini to USB B adaptor and tried several different cables, they do impart different sonic impact. Likely due to what Al refers to in his preceding post.

It's not imagination at all (I literally can't tolerate some of the cable switches/combos), but it also doesn't impact sound to the degree that a cable from the computer to DAC does (be it for better or worse).