Welcome to SDS Labs, where we have been rebuilding and repairs the Quad Electrostatic Loudspeakers for over twenty years. We can get your speakers working to the original or better specification wether it's a minor repair or a complete rebuild.

The main failure mode on the modern quad speakers is a glue failure between the thin stator and the nylon support structure

Occasionally a diaphragm will split, this seems to be more common on the newer modern quad models

Old or damaged ESL-63 electronics can be replaced with custom high performance clamp and input circuits, matched to within 1%

Original ESL-63 grilles can be replaced with very open replacement grilles (80% open area)

The most common problem with the original Quad ESLs is damaged treble panels

An original Quad ESL input transformer with rebuilt crossover and a treble panel protection clamp installed

The original Quad ESL power supply rectifiers tend to get leaky and cause low speaker output. The power supplies are rebuilt with new rectifiers and a LED neon bulb replacement circuit

A complete rebuilt set of original Quad ESL panels ready for installation

Each rebuilt panel is measured electrically as well as acoustically. This insures any rebuilding issues are caught and I provide the highest quality product for my customers

Every rebuilt speaker is burned in and measured as a final QA step to insure proper operation.