redwingsguy,
The aiwa headphone jack does the amping for you, but a seperate amp for your headphones are supposed to sound better. I'm not quite sure (audiophiles please feel free to correct me😉) but, when you have your amp plugged in to an audio-out the cd player or aiwa doesn't have to work as hard driving your headphones, so it can focus more of its power to producing good sound. Also seperate amps normaly have better quality components.
Again, if you know different, please correct me. But I'm pretty sure that im along the right lines
😀