Over the Thanksgiving weekend I got back to my headphone project and was able to complete my alteration to my Sennheiser noise canceling headphones. I figured that most of my time is spent at my computer with 5V USB power and figured there was no reason I couldn't make them use that for a power source. It was harder than expected with power being grounded to the headphone jack, I was able to make a mod to make this work over the weekend. So, now I don't have to have batteries to enjoy noise-canceling goodness. I can still use batteries which keeps the headphones at least as usable as they were.