I have noticed some say their Kemper sounds digitally distorted when playing DIRECTLY out of the headphone jack. I noticed it too. I just received my 3rd Kemper i.e. stage today and noticed it too. Here's what fixed it. I pulled out the headphone jack plug just a LITTLE and VIOLA!!!! STEREO BLISS. True stereo ping ponging with Delays etc. I mean just pull out the plug a LITTLE till you hear it clean up. I'll contact kemper on this as well. As an audio FOH mixer guy etc sometimes these things go bad and or the jack doesn't make the perfect contact. Give it a TRY!