Just received a used PODHD500X and having issues with a week distorted signal. Have used several different guitars, cables, amps etc and getting same sound out of all outputs including headphones. Input signal is set to guitar and started a new patch from scratch with nothing in the signal chain (problem still there). Signal does come through 90% clean if the string attack is harsh but any playing below that is crackly sounding and signal goes in and out similar to that of having a bad guitar cable. I'm thinking its an internal problem with the unit but want to make sure its not something simple (still figuring my way around the editing etc). Anyway, any suggestions would be helpful, tried searching online with no luck, thanks.