I'm the Canadian service tech. The clicking you hear from the unit itself is perfectly normal. Relays make noise when they switch.
You may experience a small, and I stress small pop from your speakers occasionally. That is a small amount of DC offset coming through, or possibly a little interference being picked up. Sometimes that DC is coming from the source you are using, or it could be the tubes. If it is low level, and/or occasional, then it is nothing to worry about.