Topic: Mystery static in right channel

[tokay]

I've been loving my set up, a Rode NT4 -> Sound Devices Mixpre -> Edirol R-09.  However, in the past week I've been getting static in the right channel that wasn't there before.  I only pick it up in quiet environments with the mixpre at a high gain (9 o'clock to full), and I believe it's taking place between the mic and the mixpre (I can hear the static in the mixpre's headphone jack).  To your ears, is there an obvious cause?  I'm hoping that it's the xlr cable between the mic and the mixpre and not the mic or mixpre themselves, but any thoughts would be greatly appreciated.  Here's a sound file to give you an idea (not a good recording but an especially bad case of static):

http://www.yousendit.com/transfer.php?action=batch_download&batch_id=Y1Rxb2VBdWMxUUIzZUE9PQ

[tokay]

Ok this is maybe weird.  I just did some tests.  I tried everything with the mic on battery power and, horray, everything sounded fine.  Anyway, out of curiosity I went back to phantom power to compare, but on phantom power it also sounded fine, as though somehow everything reset back to normal.  What could've caused this?  Was the problem with the mixpre's phantom power, and did I somehow magically fix this by temporarily switching to the battery?  I'm relieved everything sounds good again, but I kind of want to know what's behind all this.