Well, a copy of Audio Xpress showed up in the bottom of my Parts Express box that arrived yesterday, so I read it while I was muttering about how to cut a nice circular hole exactly 4 25/32 in diameter. (freeping drivers with no flange to speak of)
Surprise, an article about cable testing by Ed Simon. Now, there is history there, I KNOW Ed, have known him since I was a freshman at CMU, he and I were in a few lab groups along with a couple of other people who have done quite well since. (Yes, it was a fun lab group, boys and women.)
But I hadn't seen him since 1976, except for one passing in the night at an AES show. I did visit when I was at CMU giving two talks a few weeks ago.
Ed, to get back on track, has tested a bunch of cables, and solder joints.
Now, he, being a circuit hack from way back, built what I can only politely describe as an extremely sensitive test device. I saw it, and the solder joints it was testing, and the cable that was, well, "kinda" bidirectional. Now, the artifacts in question are extremely small (when you read the article, try to digest the noise level he's working at, please), but he's making measurements very near the thermal noise level, and dealt with that quite carefully as well.
The irony is that he's demonstrated, quite independently, something I've said before as well, and confirmed it with published measurements (as opposed to a simple observation in a lab), and that would be:
Connectors, basically, ****.
In fact, if you want to improve your stereo, remove and reinsert all those RCA cables 5 times, to clean off the contacts. I've proposed more than once that this is why "new cables sound better". So do the old ones, after you remove and reconnect them, I suspect.
I won't quote the data, but the advice is exactly what people at Bell Labs knew in the 1950's.
Heavy Gold Plate on Gold Plate: Best
Shiny on Gold: Not as good, and gets worse fast as metal/metal solution creates all sorts of uncool effects.
Shiny on Shiny: Not very good at all.
Finally, yes, connector and wire do matter, but again, what his data shows is simple: Competent cables with GOOD connectors are the way to go.
Not "unobtainium", just "comptent", and mind the connector, mind the connector some more, oh, and mind the connector yet a bit more than that.
And use CLEAN connectors. And clean them regularly.
I would love to use his apparatus to test some of the solder joints I've seen in various equipment, but he shows that a LOT of well-executed solder joints are much, much less a problem than one RCA connector.
No, I'm not what you'd call surprised, but it was amusing to have this all, in terms of hard measurement, just sitting there on a bench, to say the least.
Now, the level of most of these distortions is "minute" compared to the resulting threshold of hearing. Dirty connectors, however, most certainly can result in audible problems (and I don't mean so dirty as to appear nonfunctional, folks, I mean just "left in place for too long"), and clean ones may, possibly, cause a problem on low-level circuits.
Solder joints, however, as well as wire by itself, does seem to be rather innocent of all this, of course with the usual caveat that it has to be competent for its intended use.