When I sold my PF350, the new owner experienced problems—distortion, cutting out, and pops. I offered an immediate cash refund, but the problems seem to have been due to factors other than the head—or so it seems at this point . Will post an update if things change. I liked that little head, and though I only used it for about a week, I found it sounded great through an Epifani UL210, and worked well with electric and upright for Jazz. The problems with the PF500 seem to have tainted reputation of the PF350, too.