So, the video explains it pretty well, but this is the Roadie2 double bass coupler for rock band. If you have it (it lets you use 2 kick pedals, and is just about the only one out there that works properly), then you've probably noticed how fast it goes through 9-volt batteries, and there is no plug in for external power.

This video shows a very simple way to wire in an external power supply. I did it a week ago, have been playing it for about 25 hours since, it it works AMAZINGLY! Seriously, so good, I don't even have to turn it off now! No heat issues or burning or anything. If you have this thing, do yourself a favor and do this mod!

(since GS blog editor won't let me post the video in here, the link for the GS hosted and youtube hosted ones are below: (both are the same video, but the youtube one is higher resolution))

Gamespot hosted

Youtube hosted