First introduced by Roland in the late '70s, chorus effects work by duplicating a guitar signal and slightly offsetting the pitch. There are many variations on this basic concept all of which work to bring a lush, at times inorganic flavor to your sound. In the '80s, Chorus was wildly popular and pedals like the Boss CE-2 and Electro-Harmonix Small Clone could be heard all over the defining records of bands like The Cure and The Police. Chorus continued its ride in the '90s with grunge bands like Nirvana, and have seen something of a resurgence in recent years. Like other families of pedals, today's market is full of both classic models as well as a teaming world of boutique options from the likes of Catalinbread, JHS, Walrus Audio and more.