loud noise during shutdown

  • Hi,
    after many years with passive Kempers, I got my first powered rack unit the other day.
    It´s making a loud noise during shutdown.
    Searching the forum I found that it was fixed in software v4.0. I´m using the latest.
    Is my unit faulty, or the fix?

  • Where you hearing the noise? Through the cab - speakers? Is it a pop at the end of the shut down process or a longer sound while its going down getting ready to power off (reads as it is while do so)? All that really should happen is that pop at the end through a speaker but it is not very intense (unless the speakers were turned up loud). At least that is my experience. Please keep us informed and good luck. Great support here of course.

  • After some more tries, most of the time there is that soft "pop" BayouTexan is refering to. That´s ok.
    But once in a while there comes that shockingly loud bursts of noise out of my cab. At stage volume and through a PA system, the audience will faint ;)
    I haven´t detected a pattern...

  • Do U turn off the power amp first or the KPA ?

    Turn off the power amp first is my suggestion ...... :thumbup:


    Maybe a little off this topic, but not much ;)

    As an old FOH guy I would recommend everyone who has something connected to the P.A.

    ( Line instruments , synths , bass , Dj stuff , lined amps and so on ) to make contact with the FOH

    guy and confirm that it´s OK to disconnect your gear and that he has muted you channel / channels .....


    If there´s a monitor mixer guy on stage ( bigger venues ) he will probably have intercom contact

    with the FOH guy , so talk to him .......



    Cheers !

    The adjective for metal is metallic. But not so for iron ... which is ironic.

    Edited once, last by Hoki Toki ().

  • After some more tries, most of the time there is that soft "pop" BayouTexan is refering to. That´s ok.
    But once in a while there comes that shockingly loud bursts of noise out of my cab. At stage volume and through a PA system, the audience will faint ;)
    I haven´t detected a pattern...

    That sounds to me like you might be picking up some RF interference. I happened to walk across an instrument cable on the floor connected to my tube amp cab and got a loud burst of some radio commercial. Scared the crap out of me. When my foot got off the cable then the interference disappeared just as fast as it came on. The only way I could duplicate the problem was to step on the exact same spot of the cable. I threw it away.

    Larry Mar @ Lonegun Studios. Neither one famous yet.

  • latest observations:
    as long as the Kemper is not connected to my laptop via USB, there´s only this soft "pop" when shutting down.
    The loud burst only occurs when there´s an active USB connection!
    So it will be fine for live use.

    Has anyone had the same experience?

  • Good detective work! My powered unit is always connected to my Windows 10 PC (via USB). ?( By any chance would you have another laptop to test with? Good news regarding the confidence playing live.

  • I agree with Mookytc. Check another USB port or another computer. I still don't see how a USB port can cause a loud burst unless the USB is set up for charging -which still should not cause a problem.

    Larry Mar @ Lonegun Studios. Neither one famous yet.