The last few days I've been reorganising my home office / recording studio (unfortunately, they are still the same thing).
When I plugged my Korg Triton LE into my Digidesign Digi002 I noticed the distinctive hum of a ground loop. I've never had to deal with a ground loop before. Basically they occur when one device's path of least resistance to the ground is through the audio cable. The result is a low hum at AC frequency (50Hz in Australia).
So I hopped on to the excellent home-recording mailing list to ask what I should do.
Rodrigue Amyot came to my rescue with some things to try. The first possible problem we identified was that the Korg's power cable is only a two-pin (what were they thinking!)
Another possibility Rod raised was mixing balanced and unbalanced devices. I don't know what the Korg is (my Roland keyboard definitely has balanced outputs) and I don't know what the Digi002 takes although I would guess balanced. My cabling assumes both are balanced.
Unplugging the power to the Korg still left the hum which suggested it wasn't a power ground loop problem after all.
Still working on the problem. Audio electrics is fun.
The original post was in the category: record_producing_and_engineering but I'm still in the process of migrating categories over.