Just seeing if someone else has had this problem: I am using the line in (or AUX) with portable devices: cd player, md player, etc.. When I first hooked it up, I got really poor sound: very broken, almost as if it was being over driven. I fixed this by grounding the line in cables.
Has anyone else experienced this, or know the reason for it?
sheetzam s/n 73, 10 gig, blue

Yup, I had it too when I tried to feed my SCART output through the empeg!

It's caused by the ground referencing method used by the empeg for output to amps, rather than the input signal reference. The short stub lines supplied with the sled should have helped sort this out; they perform the grounding function that you carried out. Have you used these leads, or not?

The line in ground referencing isn't really designed for devices with no ground reference of their own: it's fine with a constant reference (eg, a separately powered CD head unit) but if it has no fixed ground reference it keeps trying to work out where the ground is & you get a ticking noise as it loops.

Grounding to empeg ground (or any suitable ground nearby) is fine.

Hugo