I'm having the same issue with mine. I did a factory reset then made a preset with just a rivet 120, input pad on and hit a few chords on my les paul (see attachment). Did the same with an A30. It sounds really bad? Sounds to me like a fet is clipping. When I plug headphones into the HX it sounds similar, I think that rules out a lot of possible issues with cables/interface/recording clipping etc. Turning down master volumes or adding an EQ block with -6db or so improves things but I can't see how that should be necessary?
hx stomp audio rivet 120 then a30 all defaults.mp3
