Hello, I've got a Traynor YGL2 that keeps making a high pitched feedback sound. After having the amp "fixed" three times with no luck I figured I'd try here. It sounds kind of like normal guitar feedback but worse and happens with or without anything actually plugged into the amp. It's definitely worse on the drive channel but can still be heard on the clean channel. Changing the amp settings occasionally has an effect but usually doesn't change anything. The noise stops while a note is being played but comes back as the note fades. Any help would be appreciated, thanks!