This page is dedicated to what I think is the greatest speaker ever made... the Quad ESL! It looks nothing like a conventional speaker, in fact it is more often mistaken as a 1950's radiator! While it may not produce earth-shaking bass it offers a quality and clarity of sound that cannot be matched today without spending thousands of pounds!

The Quad Electrostatic loudspeaker was designed back in 1955 by Peter Walker, the founder of Quad Electroacoustics Ltd. It was way ahead of its time, departing from conventional methods of producing sound in favour of a more elegant solution using extremely high voltages. I won't go into the technical details here as there is an excellent page explaining the principle behind electrostatic speakers click HERE to find out more.

The original ESL was replaced in 1981 by the ESL-63 which was redesigned to address some of the shortcomings of the previous model. Back in 1955 speaker designers knew very little about how drivers operated within a room, and didn't have the experience and knowledge designers have today.

The inside of the ESL is a very strange beast indeed... With the rear grille removed you can see the Mains transformer & EHT Unit, the Audio Transformer and the Bass & Treble Panels. Click HERE to view the circuit diagram of the Quad ESL.

Click on any of the thumbnails below to view the full size image.

There are quite a few links relating to Quad ESL's which can be found at SDS Labs page.