I've had my Kemper for 4 months now. Brand new. I'm experiencing the same noise. Also an intermittent problem.
- It occurs even with stomps, stack, and effects turned off.
- Front input or Alternative input.
- The only way I can get sound out of the unit that isn't affected by this noise is if I monitor the Direct out while "Guit. Analog" is selected (obviously not useful for playing, but perhaps for troubleshooting).
- The unit has been factory reset, and the newest OS is installed.
- Not the Cables.
- Not the guitar.
- It happens over headphones and main output.
- I don't have the power amp.
I contacting support about the issue, including sending them a recording. There were very helpful and quick to respond. It was determined to be a "hardware defect".
I am now waiting to hear from the US business manager to help with the repair (I haven't been waiting long). I am in London, Canada.
I'll let everyone know about my repair experience!
I should note, the process for dealing with issue has been very smooth so far.
Jake