My brother has some cold cathode tubes, some about 6" long, some about 12" or more. I was thinking of hooking them up to my bike, as shown in one of the great Instructables here, but I wasn't sure of the voltage. I don't want to over-power the tube, and bust it. Plus, the two wires coming out of it are in this black connector, so I don't know which is positive or negative. The tubes put out blue light, if that makes any difference.I have an old sports radio, which works pretty good and could be turned up really loud. I desoldered the speaker, and hooked it up to a pair of wires coming from a head phone jack. I plugged it into my iPod, expecting loudness, but no - I had to hold it up to my ear, on full volume, to hear it. Is it because the iPod isn't outputting as much voltage or current to the speaker as my radio was? The radio used 3 AA. I really wanted a portable speaker that actually put out big sound, so I didn't have to have those buds stuck in my ear.Thanks y'all!