Power amp problem

  • Hey guys, I have been having an issue with powered Kempers, I'm getting a weird doppler like effect at gigs when running a Marshall cab for onstage monitoring from the speaker output.

    Not all the time, usually halfway through the gig, I run the power amp boost at 10 and my output at my master volume is reading at minus 1.00 on the meter so it's very loud I know.

    It has happened twice now with two power rack Kempers, it sounds like the amp is going thermal, when we go into the effects loop of a spare valve amp it's fine, the main out to FOH is not effected so it's gotta be a power amp issue in the Kemper, I don't know if they have some kind of limiter in the amp or not.

    Has anyone else out there had this problem?