Never happened before but at last nights gig, my keyboardists Roland keyboard amps left and right out XLR di's added a major buzz to his amp when plugged into my Presonus RM 16 mixer. We were booth plugged into separate wall outlets with the Presonus tapping a Furman line conditioner. No real buzz in the PA but we couldn't direct him in. Any thoughts as to why?
I think @tshapiro may have nailed it. I think some troubleshooting to narrow it down might help. Could be the room; could be something new with his amp.
Sounds like grounding issues.. could be that the keys amp was on a different circuit than the Presonus and they did NOT have a common ground.
Great ideas! The keyboardist unplugged the Roland and used the infamous grey three to two ac adapter ungrounded and it still buzzed. But I'll plug the setup again in my studio.
Separate outlets. Grounding problems, or differences in ground potential. Star-power everything, or add ground lifts (any worthy DI should have one).
Fixing it for you... Avoid multiple circuits. Period. In a worst case scenario, you could risk your life with mic zaps etc.
I have a couple of dual-gang 8-outlet power drops with TWO power cables.. wired for common ground. The "poor mans" style distro that I used to use when doing SR. Works for multiple circuits.. assuming ground is correctly wired (no guarantees).. which is why I carry a circuit tester at all times. TP Audio's Bar Distro http://tjcornish.com/articles/power-and-electricity-artic/power-distribution-part-2--.html
Great article. And thanks to all for the advice. The Roland amp DI's do not have a ground lift. I guess i could make an xlr cable as a go between that has the ground un soldered?
BTW I don't think I can run the PA and my bass setup plus the keyboard setup off the same circuit. Also what is "star power"?
