I just got my Ampeg SVT-4 Pro in the mail today and I'm trying to hook it up to my Ampeg SVT-410HLF and can't seem to get a signal. The LED lights are on and I hear the fan going but I'm getting nothing. Even touching the end of the cable produced no sound. I'm playing with the same bass, chord, and cab as I did with my old head so those aren't the problem. The only thing different is the mono bridge cable that came with it. So if anyone could help me out, I would greatly appreciate it.