4
LA-3A OPERATING INSTRUCTIONS
The LA-3A is a solid state compressor that automatically reduces the level of loud signals in order to maintain
a more consistent volume level, void of loud peaks that can cause unwanted clipping and associated distor-
tion. For the remainder of this manual, the more common term “compressor” will be used instead of “leveling
amplifier” or “audio leveler”.
LA-3A FRONT PANEL
This panel has the GAIN knob, analog meter, PEAK REDUCTION knob, meter function switch (GR / OUTPUT),
meter ZERO SET control and the POWER ON switch. Each control is discussed in the following sections.
GR
OUTPUT
POWER
ON
GAIN
PEAK
REDUCTION
UNIVERSAL AUDIO, INC.
SANTA CRUZ, CALIFORNIA
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Peak Reduction
The PEAK REDUCTION control determines when the compressor receives a signal “loud” enough to trigger gain
reduction as well as total output level. Higher settings will increase the relative amount of compression. The
GR / OUTPUT switch below the GAIN knob should be set to GR to view the amount of gain reduction the LA-3A
is doing. We recommend adjusting the PEAK REDUCTION control until the meter reads between -3 and -5 on
the meter during volume peaks. NOTE: adjusting the level of the device that’s plugged into the LA-3A input as
well as adjusting the PEAK REDUCTION control knob can affect the amount of compression. Heavily compressed
signals can be made louder by increasing the GAIN knob just to the left of the meter. See “Side Chain Circuit”
on page 14 for technical details.
Gain
The GAIN control behaves like an output level control. Turning this control clockwise will increase the output
level of the signal at the output jack on the rear panel, typically feeding a mixing console or recording device.
The GR / OUTPUT switch below the GAIN knob should be set to output to view signal strength on the LA-3A me-
ter. When the LA-3A is in deep compression, signal level is reduced. The GAIN knob is used to restore the signal
level.
Meter Function
The LA-3A VU meter can be used to indicate compressor gain reduction or final output level. The meter
