I recently got this recevier and am not sure how to hook this up to a headphone amplifier. I am using an optical input as the source and have tried to use every output I could think of including the tape monitor (tape out)/pre amp, you name it. I'm running out of ideas. There is a slight hum in the headphones and that's it. As I say, I am new to this receiver and may just be overlooking something simple...? The Amp is a Prelude Symphony (which works great with other sources) and the headphones are Sennheiser HD650s.

This has been driving me nut, please help!