I recently got a used HK3490 for cheap and am trying to make the most of it with my student shoe-string budget. I'm pretty new to this audio gear stuff so even basic things I'm abit unsure about - which leads me to my question: I got a 3.5mm to RCA cable which allows me to hook up my ipod or macbook air (no optical out sadly) to the receiver. But I only get sound when I hook it up to the "Main Input" on the backside - when I try any other of the RCA inputs (cd in, vid3 input on the front panel, etc), I don't hear anything at all. Maybe I'm missunderstanding something really simple, but why is this the case? I've tried googling it but can't seem to find the answer I'm looking for.
Thanks for any help!!