Massive Earth loop in my Monitor out Jacks

    Hi all


    I'm having lots of earth radio frequency noise coming out of my monitor outs on the Kemper Stage.

    The main XLR Outs to the FOH are fine

    I use 2 x Boss Katana's MK 2 100's for stage monitoring. I go into the power amp in on the amps.

    I use mainly hi gain sounds in my stage

    When I move the cables connected to the amps around the frequencies changes, they may slightly get better or a lot worse. But never disappears. :cursing:


    Things I have tried to remove the annoyance:X(

    - Changed a number of cables, mostly new.

    - Balanced and Unbalanced jacks

    - Monitor ground lift in the unit

    - Remove earth pin in power cable (just the unit)

    - Plugged into different amps / monitors


    I haven't spoken to any audio technicians or connected into a Di box (my next try)


    Has anyone here had similar challenges?

    Did you solve the issue, how?


    I'm not a beginner, been in the music indus for too many years


    Thanks for hearing me out. :)

    I had a instrument cable once that if I stepped on a certain spot I would pick up all kind of radio stations pumped into my cabs and when I stepped off the interference went away. It was a brand new cable like one week old so I had it replaced and it got resolved. That's the only thing I can think of.


    You can maybe go back and replace one cable at a time again until you find the problem and/or try moving equipment around if they are in same location as before when it happened.


    Or you might have to get a roll of Aluminum Foil and start wrapping equipment to prevent alien interference and abduction. ;)

    Larry Mar @ Lonegun Studios. Neither one famous yet.

    Ugh. Gremlins like this are maddening .


    Like an auto mechanic diagnosing an electrical fault, start at the beginning…..(some of this you may have done…I suggest doing it again in sequence)


    Strip your rig down to just enough to work. Guitar, cord, KPA….


    Does it happen in headphones connected to the KPA? Using a different guitar cord. Power cord?


    Try a different location’s power? Not a different plug in the same building. Different venue.


    If it’s still doing it….gotta be the KPA. If not….keep adding pieces. You’ll know to stop testing when you find the configuration that created the problem.


    Hope that makes sense, and helps.

    “Without music, life would be a mistake.” - Friedrich Nietzsche

    Like 1

    Yeh, thnx for your thoughts


    No bad signal in my Headphones or Main XLR outs, they are clean of any ground loop.

    Its only my Monitor Outs


    Tried different power cords, different wall plugs, guitar cables

    The issue happens in different venues.


    My system is very simple uncomplicated.

    Gtr into KPA

    L R Main XLR outs to FOH

    L R Monitor outs to stage amps


    Thnx once again

    Hi, Robbon.

    Are the 2 x Boss Katana's MK 2 100s plugged into the same AC power source as the Profiler?

    Hi ST


    Good thought,


    I have just tried plugging each unit into separate power sockets around the room, unfortunately no change.


    I'm just wondering, do any of you use your monitor outs in stereo and have any issues?

    Hi, Robbon.

    What intended, was that you try plugging everything into the same AC source (e.g., power bar) so that all were connected to the same common ground.

    At this point, you need to contact Kemper and submit a support ticket.

    Seems the KPA is responsible.

    “Without music, life would be a mistake.” - Friedrich Nietzsche