Quad ESL-989

In 1995, Quad Acoustics was sold to the Verity Group, which at that time owned Mission Loudspeakers. In 1998, International Audio Group (IAG) purchased Quad, and set out to remanufacture the classic ESL-63 using modern methods. They first produced the ESL-988, a direct replacement for the ESL-63 that retains all of its original features. The rigidity of the speaker's frame was improved, and 95% of the components were upgraded. IAG improved the quality of wiring in the delay lines, and increased the concentration of copper in the electrodes. All new Quad ESL models were given a 5 degrees backtilt.

They also produced a new model, the ESL-989, which had 50% more radiating area than the '63, weighed about 11 lbs more, was nearly 16" taller, and had two additional bass panels for improved low-frequency performance (-6dB at 30Hz vs the '988's 35Hz rating). The '989's power handling was also increased, particularly in the deepest bass range. Quad's Julian Maddock stated, "The '989's protection circuitry is all but identical to that found in the ESL-63, albeit with higher-quality components. However, the upper voltage limit for the ESL-989's protection circuit has been increased, due to the greater power handling and low-frequency performance of the larger diaphragm.

Previous Next

Klik op de afbeelding voor een vergroting
Click picture for magnification

Quad ESL-989 electrostatic loudspeaker
Full-range electrostatic loudspeaker.
Power capacity: 100W, 10V RMS, 40V peak maximum signal input.
Program peak for undistorted output: 40V.
Permitted peak input: 55V.
Impedance: 8 ohms nominal, 6.2 ohms minimum.
Sensitivity: 86dB/2.83V/m.
Frequency response: 30Hz-20kHz, +/-6dB.
Dimensions: 52" (1335mm) H by 26" (670mm) W by 12.25" (315mm) D.
Weight: 55.7 lbs (25.3kg) net.