I just picked up a Tone Hammer 500. I have two 1x15 cabinets, each 4 ohms, so I can't run the TH500 with both cabs. I have a Walkabout head, so I tried connecting the TH500 to the Walkabout's power section by running a 1/4" instrument cable from the TH's send to the Walkabout's return. I connected a 1x15 cab to each amp. I was able to get a signal to the Walkabout, but it was a set level, the master control on the Walkabout didn't adjust the volume on its cab. The TH's master volume functioned properly on its cab, but the Walkabout's cab wouldn't change no matter what I did. Am I doing something wrong? I want to be able to adjust the volume on both heads/cabs and use the TH's preamp exclusively.