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Quad Electrostatic Loudspeakers
The 99 power amplifiers are fully compatible with the Quad ESL-63,
ESL-988 and ESL-989 loudspeakers. It should not be used with the earlier
model ESL which could be damaged by signal peaks unless a protection
circuit is fitted inside each loudspeaker – please contact Quad
Electroacoustics for details.
Loudspeaker Phasing
If there is any doubt about the way the loudspeakers are connected, their
phasing can easily be checked by playing a mono source, when the sound
should appear to emanate from a point midway between the two
loudspeakers. If this is indefinite, then the connections to one of the
loudspeakers should be reversed. When correctly connected, the
loudspeakers will give a definite centre sound source with more full bodied
tenor and bass registers.
Headphones
Headphones will normally be used instead of loudspeakers and there are a
number of suitable switch units available designed to enable the
loudspeakers to be switched off when the headphones are plugged in. Most
of these incorporate a simple attenuator circuit to permit operation at
normal settings of the control unit volume control. Electrostatic or other
types of headphones requiring a high level input should be operated in
accordance with the manufacturer’s instructions.
