Fail Of The Week: Cat6 != Coax

With a new Kenwood 5.1 receiver acquired from questionable sources, [PodeCoet] had no way to buy the necessary coax. He did have leftover Cat6 though. He knew that digital requires shielded cable, but figured hacking a solution was worth a try.

To give hacking credit where credit is due, [PodeCoet] spent over a decade enjoying home theatre courtesy of a car amp rigged to his bench supply. Not all that ghetto of a choice for an EE student, it at least worked. To hook up its replacement he pondered if Cat6 would suffice, "Something-something twisted pair, single-sideband standing wave black magic." Clearly hovering at that most dangerous level of knowledge where one knows just enough to get further into trouble, he selected the "twistiest" (orange) pair of wires in the cables. Reasonable logic, one must select the strongest of available shoelaces for towing a car.

It worked perfectly unless anything electrical happened. Any electrical occurrence at all (plus, according to him, occasional Arduino voodoo hexes) caused the Kenwood's audio relay to trip off and go into standby mode.

Probably gamma rays from the freemasons.

Umm, nope. Well, when one buys "second hand" products like this that is possible, but, Occam's Razor gives you a more likely solution.

It turns out that replacing the cable with some shielded coax made the problem disappear. So that clears that up; unshielded Cat6 will not work for digital audio cable. That is something many of us did not definitively know until now.

To our smarmier readers who blew a gasket over [PodeCoet] trolling his Prof last month, allow yourselves a smug moment to bask in the light of his karma coming due. He owned up and submitted this fail. The rest of you should do the same so we can learn from your mistakes and enhance the greater knowledge of the community and well-being of mankind everywhere.

Fail of the Week is a Hackaday column which celebrates the learning potential of failed projects. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.