Is there a warm up time associated with the Kemper? I bought my Kemper new from Sweetwater and noticed when I plugged into my Alto speakers that there was a rather loud high frequency hiss that gradually went away after 5 minutes or so. When it goes away it almost sounds like the the hiss is stuttering. I unfortunately thought that this was the Alto speaker doing this cause I didn't get that same sound on the headphone jack, however, I noticed it when going into other speakers and when plugging the main outs into my DAW interface. So in other words, its the main outs doing this. Anyone else experienced this? I'm unfortunately past my 30 day return, but maybe I could talk with them at Sweetwater if this is a faulty system. After the hiss goes away I do get the random buzz sound that go buzz...click on the output but I haven't fully determined if that's the Kemper or something else. Thanks all.