Henry on our forums wanted to know how to do a fairly complex setup with 3 FX150's in stereo and mono for monitoring in two locations. Craig throws up a diagram to show you how he'd get it done.
You'll need a few XLR cables and maybe an 1/8" inch or two as well.
Here's the forum thread question: http://support.tc-helicon.com/entries/67943783-FX150-digital-analog-circuitry-and-true-stereo-set-up