'Bass End Feedback' Type Error in 4.0.1?

    I had this issue both Friday night and last night with the KPA.


    A loud low end type feedback sound came out of the KPA in the middle of 2 different songs.


    Straight away I turned the guitar volume to zero - made no difference
    so I turned main volume down to zero ...made no difference
    Finally I turned monitor to zero - made no difference


    The desk was getting the same horrible low end feedback tone.....


    I had to restart the KPA to stop the sound.


    The second time it happened was last night .... I had a different cable to KPA , different cable to monitor , different XLR's to FOH


    Both gigs were with different bands , different venues , different cables , different monitor cab , different desks .... the only similar pieces of gear used were the guitar and the Kemper.


    This is the first time in 4+ years that I've had this issue.I updated to 4.0.1 last week.


    Has any one else had this problem ?


    Any thoughts ?


    I haven't opened a ticket yet but may do so in the morning once I check that the guitar is ok


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    I had a similar problem yesterday playing through Kemper power stage, seymour duncan powerstage 700 and two kabinets. Never happened before. There was a low "bass" frequency feedback rising up when I stopped playing. The low cut output frequencies are already cut to 100Hz (though maybe it doesn't work for the monitor output and only works for the main output, now I'm not sure about it). Really don't understand why that low feedback happens. Any help will be truly appreciated.