How to hook up home amplifier to tuner?

I've got a 5.1 home theatre setup, today I bought an onkyo line conditioner/amplifier that pushes 150w of power to each channel, I was needing it to push my jbl northridges. Question is, before I pull out my tv & everything I need to know what it is i'm hooking it into to provide a constant signal, the external amp has a pair of l/r rca style inputs. If I remember correctly the only thing on a tuner that provides constant signal is the sub line & the monitor, and the monitor is only a single connection, so any ideas what to do?