Had the same Problem and can produce the same issue when playing clean crispy sounds. (Typical SC)
I think it is more a matter of volume settings in the profile and not so much the clean sense. (0 must be OK)
I use an eq with high cut at approx. 8-9 KHz and lower the volume before the stack (or in the amplifier or cab).
Reducing the Master volume or RIG volume don't help as far I considered.
What is your output level? I have to set it lower than -20 dB otherwise this noise come easy.
I can not explain why this help - but it helps. Don't have the Problem anymore.
So I was playing with these profiles (BTW I am using Bert Meulendijk Kemper Profile Pack, specifically his Bogners and Plexi's that I purchased - and I just want to say - they are worth every dollar I paid, best damn sounding profiles to date; the problems are NOT the profiles or Kemper per se' - just to be clear) - I found out a few things. (To answer some other questions - there are no external stomps these are all "virtual stomps" from Kemper. All outputs levels set to 0)
1. Turning down distorted sense by 2db somewhat helped - but still had the weird artifact/sound, just not as loud.
2. I have a compressor in stomp slot 1, which had it's output set to +2, the Distortion Plus is in stomp slot 3 (this is what I like to use for drive). When hitting a power 'A' chord or 'F' chord, the compressor, I guess, is driving the 'Distortion Plus' into some weird harmonic overdrive, not every chord but - really, really, really sounds like shit - totally unnatural - totally digital & computer sounding - turning it off and/or down seemed to resolve the problem but I loose the smoothness of the compressor. However, this is confusing because with the overdrive stomp turned off and compressor stomp engaged I do not hear this but when I turn the Kemper Gain Knob up to 50-75% I hear the exact same artifacts. Why?
I really think this is strange behavior because when I use my Whampler Ego in front of my OCD Overdrive into my Physical Boogies or Marshall's I never hear artifacts like this only smooth tone - thoughts?
3. Gain staging seems to be the problem here, I think, but not 100% sure - since there are no overload indicators on the stomps there is no real way to determine if I am overdriving another stomp, but question still stands what is this compressor doing that would cause weird/added harmonics even when the gain control is increased???
4. You cannot treat your Kemper stomps like you would your analog gear - Kemper sounds amazing, no doubt about it, but at the end of the day - it is still a computer. You need to really tailor your sounds to your axe and playing.
Cheers,
Brad