A portable CD player with a line output will not take up much space. That said, most of them stink sonically. I am using the Radio Shack CD3400, which is one of few portables that have a decent line out, but I am feeding its linestage into the analog inputs of an unmodified Art DI/O, converting to digital and then looping back into the DI/O's digital input converting to analog at 24/96. This sounds better than using the Radio Shack's digital output into the DI/O, especially since I am using the tube warmth feature of the DI/O. I would warn that I do not think the CD3400's can be serviced any more, so if you find one, make sure it is in good shape. Only problem I have ever had with mine is the jacks are a little worn.