You guys have both got me wrong.
Frankly, I think that the cables in question, and for that matter essentially every piece of "audiophile" wire ever peddled, is a load of crap. I think the cottage industry surrounding the cables is run either by delusional idiots or criminals, and I can't think of a single more ancient technology that has as little room for improvement as audio cable.
I am delighted with both your and JT's results because you are both obviously sincere people who were unmoved by the make-believe claims that people make about these conduits of snake oil. My complaint or lament, as it were, is that despite all the trouble you went to, ad hoc personal test results like these cannot be used as ammunition to flat out discredit the companies who peddle this stuff, which is precisely what my heart longs for. Nothing would make me happier than to make it impossible for people duping musicians to earn a living doing it, but without a double blind test, all the snake oil men have got to do to discredit your results is find a couple of people who say "oh yeah, I hear it!". So I'm not criticizing your conclusions Tim, just whining that I wouldn't be able to use them as definitive proof that the cables don't do anything.
Just like sleight of hand magic works by capitalizing on weird quirks in human perception, the audio cable ripoff trick works by exploiting a weakness in human hearing- it's interface with short term memory and the way aural perception fits into cognition. I swear, I'm not making this up, and yes its complicated but it really does matter when you are talking about using human subjects to detect small changes in audio signals. Bear with me.
Psychiatrists and scientists who study cognition have learned that any time you are doing an experiment to determine the threshhold of perception in a person (i.e. how sensitive the eyes/ears/nose are to changes) it is impossible to obtain accurate results if there is any transmission of information between the subject and the administrator of the test (in this case its you, since you were switching cables yourself). Daniel Dennett refers to this as the
heterophenomenological experience, which is just a fancy way of saying that my brain perceives differently when someone else tells me or shows me something, or when I am aware of some piece of information that might affect how I perceive things. That's suggestion.
In both your cases, you went into the test feeling pretty objective. You knew the differences, if any, were probably going to be very slight, and you were listening hard, and you had decided not to make up your mind ahead of time. That's perfect. One of you heard a difference with the instrument cable and one didn't. Thats ambiguous but its ok, we'll have more results and we can use our stats knowledge to sort out an answer once we have more samples. The problem is that once we have those results, we have to be prepared to respond to complaints that somehow suggestion was used to guide responses. The cable company could claim that the color of their cable set off testers, or any number of other things. Or they could claim that the period of time taken to swap cables was so long that it was hard for the tester to listen really closely. Unfortunately, they'd have a point, because dumb subtle things like the appearance of the cable can and really do cause variations in big tests.
So anyway, my only gripe was that double blind testing is not just some extra thing you'd do in addition to ad hoc testing, it's the ONLY way you can do a test like this and have the results be valid enough that you could actually win an argument with the people who disagree with you, or conversely, its the only way that a intelligent person can know that they were mistaken about something they thought they heard. So say it turns out I'm wrong and the cables work as promised, I want to know for certain, and I need to test to be clean for that.
The rest of this doesn't apply to Tim or John:
I have done these kinds of ABX tests before and I have learned the hard, embarassing way that if you have knowledge of a change in the test setup, a different cable or power amp or whatever, you can no longer trust your own perception of sound. A lot of musicians are kind of religious about their own ears and they are certain that they'll simply be able to hear these things or not hear them, but they forget or don't understand that their brains are there trying to give them every possible advantage in what to the subconscious seems like a contest, and you will honest-to-god hear things that are not there if the brain can correlate a sound with some kind of switch. It makes you more, not less credible, if you don't completely trust your own ears.
I recommend
http://www.pcabx.com/getting_started.htm for an example of how hard some of this stuff can be to hear. A lot of people would assume that they could hear, for example, 1% thd in a signal, but give it a few whirls in PCABX
