A friend of mine got a pair of monitor speakers, something I have never had or dealt with. He says the plugs for them are 1/4 TRS plugs, or in other words "The one that looks like a big headphone plug." Would a modern receiver have an input these can be plugged into or would an adapter be needed? The only thing I can think of is the set of Pre-Outs on some receivers, or the 5.1 output. Would either of those work? He basically wants something to plug the speakers into, and then plug his iPod into. Simple goal but have a feeling might not be that easy to obtain.