Unfortunately, all the bad things about that Koss EQ unit are true - and then some. The Koss EQ also has practically no headroom in its output - that is, there is hardly any leeway between the volume level at which the EQ produces sound and the volume level at which the EQ's output begins to distort.
If you really, really, really would like to have a PCDP with a graphic equalizer, you can try a model made by GPX. I can't find their website, but it should be avaible in a lot of places. Be warned, it probably is not a very good or reliable player.