QUAD was a NAME revered by those who were into hifi sound during the 1950s, ’60s, ’70s and ’80s. Founded in the UK in 1936, they made a name for themselves building high-quality power amplifiers, speakers and other audio gear. They introduced the world’s first full-range electrostatic speakers in 1957.
So when our very own Serviceman told us he had inherited a Quad electrostatic system from a relative in the UK and asked if would we like to listen to it, we jumped at the opportunity. At the forefront of our minds was the question: how would the legendary Quad system compare to the best audio equipment available today? Did it deserve its reputation?
Line-up and appearance
The system consists of seven components: two Quad ESL63 electrostatic loudspeakers, one Quad “L-ite” subwoofer, the amplifier/preamplifier/FM tuner group and a Quad 66 CD player (a relatively recent addition).
The ESL63s are second-generation electrostatic speakers introduced in 1981. Their appearance is consistent with that era – whether that is a good or bad thing depends heavily on taste. The subwoofer has a more modern, polished metal appearance with a LED display at the front.
The amplifier/preamplifier/FM tuner
group is made of three distinct units stacked in a small wooden cabinet, which is painted dark grey to match them. Individually they are the Quad FM4 tuner, Quad 44 preamplifier and Quad 405-2 100W Stereo Current Dumping Amplifier. Interestingly, the amplifier pre-dates the ESL63 speakers – it was released in 1975 and was regarded as a landmark unit at the time.
Their front panels feature nicely machined metal switches, pushbuttons and knobs. Because all mains power passes through it, turning on the preamplifier also turns on the other components. It has five stereo inputs, a volume knob with 22 detents, a bass lift filter, a “tilt” filter (which cuts treble while it boosts bass and vice versa) and an adjustable low-pass filter. There is also a balance control and a stereo/mono switch.
The FM tuner is rather simple, with seven station preset buttons and a manual “tune” button. Tuning is accomplished with a knob and the nearest frequency (to within 50kHz) is shown on a digital display.
The power amplifier has no front panel as such, instead sporting a substantial black, finned heatsink across the full width.
The Quad CD player is similarly spartan, with just a power switch, eject button and display. The other controls are on the remote. Similarly, the subwoofer controls are handled entirely by the infrared remote.
Fig.1: the frequency response of the Quad 405-2 amplifier. The -3dB points are 15Hz and 35kHz, which is within its specifications but not as flat as many modern amplifiers.
Fig.2: THD+N vs Power for the Quad 405-2 amplifier at 1kHz/8Ω, measured with a 20Hz-22kHz bandwidth. Its distortion at low powers is relatively high due to noise.
Before we begin discussing the performance, it is worth explaining how these speakers work.