I have a problem with my Kabinet / Kone. I use a powered toaster to drive the Kabinet, obviously using the speaker out. As of this morning, when increasing the volume, there is a high end rattle in some of the notes, some notes more than others. This is present both with clean rigs and distorted rigs, it's really only volume dependent. On low volumes the Kabinet sounds like what I'm used to, but all of a sudden, when increasing the monitor out volume of the KPA, some notes sound very fuzzy, distorted, in a bad way.
Could this be a broken Kone? I've removed the back panel but I don't see any damages on the speaker. Is there any other way to check?
Thanks a lot!