If you don’t own a power conditioner, you’re living dangerously as far as your AV receiver is concerned. (Not to mention other AC-powered digital devices, like your computer.) Lightning strikes, power outages, or brownouts can destroy delicate electronics in a flash, which is why we always recommend buying a power conditioner to protect your valuable equipment in the event of sudden over or under voltage. Audioquest, Furman, and Panamax make some of the best.