Alesis Andromeda A6 Tips And Tricks Manual page 91

If (no buzz) then (we work with your PC next). Isolate everything on that one too. Unplug your
internet connection, your printer, your USB stuff, your scanner, your digital audio stuff,
EVERYTHING. You should only have your monitor, keyboard, and mouse hooked up. Then
connect MIDI from the PC to the A6 and see if it still buzzes.
If there is no buzz so far, then plug stuff back in one at a time until the buzz returns; you found your
culprit. Once you find it, there is no single solution that will get rid of it; you might need to correct
the power distribution, your cables might be picking up interference if they're too close to high-power
devices (monitor, power amp, AC, etc), you might need a two prong adapter, you might need an
audio cable with one end having ground disconnected, you might need to isolate the rack chassis
from the rack (two words: Voyetra-8), could be any of these. I had an FX unit where I needed to
float ground in one of the output cables to get rid of the buzz.
It's hard work but that's how you find a needle in a haystack. That's why studio engineers are worth
their salt. I have a slight buzz to conquer since I added my patchbay a couple of months ago but
there are higher priorities to take care of first.