I needed to run a series connection for two 4 ohm cabs to show my amp 8 ohms. I noticed that only one cab would play. Switched the ends plugged into each cab and the same thing. Cable tested fine. As it turns out, the 1/4" plug on one of the ends needs to be ALMOST all the way in or it won't work, so problem solved, but now I have a question that's bothering me: Being a series cable, how did only one cab work at all? Shouldn't it have been an "all or nothing" deal?