Bad buzz, poor connection, grounding problems

The HA400 will pick up interference as a pretty loud buzz from the power charger on my laptop, but other than that one source of interference it puts out a clean signal

The worst is the annoying 60Hz buzz

I unplugged them from the amp and plugged them straight into the board and PRESTO, no more hum/buzz

For the price, I'm happy with it and get no extraneous buzz even though it's on a large desk with a laptop, HD monitor, 2 external hard drives, and an xbox360.

Clean sound no buzzing or interference

If the surface it sits on gets hit or slightly moves, you get loud buzzing and have to readjust connections

Once everything was done I was getting a terrible staticy hum/buzz in the headphones