Don't know about the cold cathode, but I did mine with 4 led's that originally had 18 on a string and were powered by a 4 AA battery pack. They were sold as a christmas light set at target and came in blue, red and white (each set was one color) I bought the blue. I re-wired the led's how I wanted them with spacing and so on and only left 4 on total. I bought a 6V 300ma AC adapter and wired it in...Presto! Works great! I would imagine that one would be enough if you go with the cold cathode, depending on how bright you want it to be. I'm sure someone else has more experience with them.