ART Pro Audio Pro Channel - Mic Preamp/Compressor/EQ - Manual (Page 12)

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+10dB of gain (when turned fully clockwise).
When setting up the preamp, start with the Preamp Output at its “0” position. Once you
get the Gain control set the way you want it to sound, use the Preamp Output control to
set the level out of the preamp (much like using the master volume control on a guitar
amplifier). Use the Preamp Output control to recover gain when you have the Gain
control set low for a “clean” sound. Likewise, you can use the Preamp Output control to
decrease the level out of the preamp when you’re cranking the Gain control up for
maximum tube warmth. Don’t be afraid to set the Preamp Output control very high if
you desire a very clean signal, but with a good deal of compression. (See the next
section.)
Compressor Circuit
Threshold Control
The Threshold control sets the point at which
the compressor acts on the input signal.
Turning this control counterclockwise lowers
the Threshold, adding more compression to a
signal. Turning this control clockwise raises
the threshold.
The Threshold control is dependent on the
Preamp Output control (or the output of a
device plugged into the Comp In insert point).
The easiest way to set this control is to start
with it fully clockwise. After setting the
Preamp Output level, slowly turn the
Threshold control counter-clockwise,
(lowering the threshold) until you see the
yellow (0dB) Threshold LED light in the Gain
Reduction display (below the Tube Character
array). Now adjust Threshold (either lower or higher) until you have the desired amount
of compression. (Use the Gain Reduction LEDs as a visual guide)
Ratio Control
The Ratio control sets the compression ratio (or slope) for the compressor circuit. At its
minimum position, the compression ratio is an active 2:1, meaning that for every 2dB
over the threshold the input signal rises, the compressor’s output will change by 1dB.
This compression ratio is very mild and musical, and is ideal for smoothing all types of
signals. At its maximum position, the compression ratio is greater than 10:1. This
setting is typically called “hard limiting” as it allows only a 1dB change in level for any
signal reaching 10dB above the set threshold. Hard limiting is ideal for applications
where it is not desirable to exceed a certain level (i.e., mixing, popping bass, digital
recording, etc.).