Okay, I'm probably asking a stupid noob question, but here goes... I have a few regular-polarity pedals and one reverse-polarity one. I just got the 5-point power cable for my 1 Spot power source. It works great when I only use it for the regular-polarity pedals, but once I put the reverse-polarity adapter on they all stop working. After a few seconds of silence, a thumping is heard through the amp. If it makes any difference, I put the reverse-polarity adapter on the first pedal in the power line. What, if anything, did I do wrong?