over the last few days, i've once again been stuck with fading.
i ripped the machine right down and was still getting the same problem from asio with everything else uninstalled and disabled. so, i defaulted back to the phones being the issue and noticed something i hadn't realized before - i didn't actually have to reset the jack, i just had to touch it.
i ended up back at interference, and was finally able to get a cause and effect relationship in cycling the receiver.
i'm not entirely sure, still, if it's magnetic or electrical. i think i may have been creating a field by coiling the wire (although that sounds ridiculous, given the voltages involved). but, i've cycled everything, reset the load on the electrical chain a little and grounded all the soundcards and audio paths through the same power bar.
i think i'm stable. if i am, expect some quick confirmations. if i'm not, i’m essentially at an impasse and have nothing left to do but buy some more cords in desperation.