'Glitches' means that the music is distorted every couple (say 5) of seconds for a second or so. It seams like there is an additional high level signal on the Aux in line at that moment. May be it is there all the time but only noticable at certain moments.

All equipment (Empeg, amplifier and cd-player) share the same power outlet (a regular 220V wall outlet). Aaah, now I see the cd-player is not grounded! And running the wire clearly solves the issue since this is the same as holding the sled and the Aux in connectors at the same time.

So, I quess I will just connect the cd-player and the sled by a wire. Ugly and strange, but it solves the issue.

Thanks for showing me that I had to connect the cd-player and the sled, that did not occur to me yet.