Hey all, first post here.
Ever since I bought the Kemper back in 2019, I've been struggling like many to get a high-gain tone that didn't sound fizzy. It was especially problematic when switching chords - it would create this weird chirping sound from the attack and from the tiniest string scratch. VSTs sounded better, and I've read many of the problems that people have had which is why I wanted to post my personal solution which is so simple, it's painful:
I simply turned the volume knob on my guitar to lower the pickup volume. Many of us are so used to having the tone and volume knobs cranked for other types of amps and VSTs, but with the Kemper, it's too hot. I knew my pickups were hot but it never dawned on me to turn down the knob on my guitar about halfway. I would always try and turn down the gain on the Kemper or try and set some other setting. Btw, I have an Ernie Ball Music Man RS guitar with stock pickups.
A glaring tell is when you go to the Rig Manager and see that a profile's gain is a 4 out of 10, you play it....and you get a heavier distortion sound instead of a fair crunch sound. The moment I turned the guitar itself down about halfway, all of the sudden, I got the correct level of distortion from high-gain profiles, the fizz is gone, and everything sounds as it should. It's embarrassing but I had to mention it because I can have that same volume knob cranked all the way up in VST amps and it's fine. Not the case with the Kemper profiles.
Every time you demo a high-gain profile, turn the guitar's volume knob down to where it's too clean, then bring it back up until there's just enough distortion. And if somebody comes along and asks why their guitar tone is so bad, I recommend mentioning this guitar volume knob as the first thing to check.
One good profile to test their level in the Rig Manager is to use:
"DP \'65 Deluxe Crunc" by the author "Heater."
When my guitar's knob is down where it now should be, this sounds like a fairly good crunch tone. When the knob was all the way up on the guitar, this profile suddenly becomes a full-blown distortion sound when the rating is a 4 out of 10 in terms of gain...so that's the first sign that things are too hot. This particular profile's higher gain happens to sound pretty good when the guitar's knob is all the way up but it's not meant to be a high-gain profile and so this is a good way of telling where the guitar's knob should be. Then toggling through other profiles gives me this starting point where things suddenly start to sound pretty good.
I can already tell that many people will be shaking their heads at this obvious advice, but it's apparently not so obvious to many of us! 