What would be a simple (and inexpensive) way to playback a stereo recording (CD) so that in the playback there was access to a full, clean pan control: that is, so that one could listen to either the right channel or the left channel or both. (Moving them is not an issue.) My own CD amplifier has a balance control that adjusts the relative volume of the two speakers, but it does not eliminate either channel even in an extreme position. I have the impression that when set to extreme right, for example, it directs both the right and left channels to the right speaker.