Basic Operations; Using The Preamp Alone; Processing Section; Compressor - dbx 286A Owner's Operation Manual

Mic Preamp/
Processor
286A
B O
ASIC PERATION
Understanding the 286A's Mic Preamp
Using the Mic Preamp Alone
(i.e., Using the 286A as a
Dedicated Mic Preamp)

Processing Section

4. Connect the AC power cord to the AC power receptacle on the back of the unit.
Note: We recommend you always power on the unit with the MIC GAIN control set to its minimum level
(fully counterclockwise). This will help in safeguarding your system against sudden spikes and surges, as
well as possible acoustical feedback if a microphone is connected and left "open."
Note: Check the line voltage (printed on 286A) and verify that it is correct.
The 286A's Mic Preamplification Section includes support for phantom-powered
mics, a highpass filter, and an input gain control. Note that these controls are applied
to the input signal before the signal is processed by the 286A's Processing Section.
Phantom power is available at the push of a button, providing +48VDC to phantom-
powered microphones. The 286A's phantom power is sufficient for most micro-
phones, However, some vintage condenser mics may require a separate power
source.
Press the HIGHPASS button In to cut signals below 80Hz by 18dB/octave, effective-
ly filtering out mic proximity effects, hum, rumble, wind and other low frequency
"undesirables."
Use the MIC GAIN control to achieve the best definition and character possible from
your microphone. The 286A's Mic Preamp delivers up to 60dB of sonically transpar-
ent gain to reveal the detail and audio signature of even the most esoteric mics. It
transforms their low level output signal to a high level, high current signal that is
internally fed to the 286A's main processing chain (i.e., compressor, de-esser, etc.)
To use the 286A as a dedicated mic preamp, simply press the BYPASS button to
defeat the Processing Section circuitry. This allows you to use the Mic preamp's
PHANTOM POWER switch, HIGHPASS button and MIC GAIN control without
routing the signal through any of the processing circuitry.
The 286A's Processing Section consists of four specific processors: Compressor , De-
esser, Enhancer, Expander/Gate. These four processors can be used in any combina-
tion or the 286A can be set as a dedicated single-function processor (refer to the fol-
lowing pages).
A compressor is a device that changes its gain in response to the signal at its input.

Compressor

Many compressors have a user-selectable level, called THRESHOLD, to help deter-
mine when compression occurs. If the input signal is low in level (below the thresh-
old of compression) the compressor gain remains fixed. If the input increases above
the threshold of compression, the gain begins to decrease (i.e., the amount of gain
reduction increases). For very large input signals, the gain can decrease considerably.
On the 286A, compression occurs as an input level is "driven" into gain reduction by
the DRIVE control; as the DRIVE setting (adjusted clockwise from OFF) increases
input gain, the amount of gain reduction also increases. The 286A does not have a
Threshold control; the threshold is established by the setting of the DRIVE control.
Use the Drive control to set the amount of gain reduction (i.e., how much the input
signal is being compressed). Use the DENSITY control to set the compressor's
OUTPUT jack.
C. Connect an external processor or effects device to the 1/4" INSERT
jack. (Optional)
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