Quad (Acoustical Manufacturing) · Quad electrostatic speakers

Quad Electrostatic Loudspeaker

The electrostatic that defined the Quad sound and stayed in production for 28 years.

Catalogue code: ESL
Years: 1957–1985
Type: full-range electrostatic speaker
Valves & speakers: Full-range electrostatic loudspeaker, 54,000 built; needs a mains supply for the polarising voltage
Lifecycle: retired
Confidence: High

Specifications

Technology: electrostatic
Channels: 1
Inputs_outputs: single pair of terminals

Safety

Electrostatic panels are charged from the mains: unplug and leave to discharge before touching panels; refurbished panels are the main cost item.

01 / Witnesses

What applies here

Marks that can be entered for this maker: Serial number, Model / catalogue number, British capacitor code (Hunts, Mullard), Japanese capacitor code (Nichicon, Chemi-Con, ELNA), EIA component code, Version & era marker.

02 / Bounds

The model year is a floor

Nothing predates 1957; components only push the date later.

03 / Value

What moves the price

Sold-price aggregates are not collected yet, so the archive gives no figure — condition, originality of the transformers and a documented recap move this model more than any list price.