MPA575 Quick Start Guide
5/2014
1
QUICK START GUIDE
The MPA575 features a lightly colored transformer coupled discrete microphone pre-amplifier,
program dependent soft knee compressor with auto make-up gain, a see-saw EQ with
combined low and high frequency control that allows broad tone adjustments with a single
control knob, and a High Pass (Low Cut) filter with variable cutoff frequency. Together, they
form a mini channel strip that performs all essential analog signal processing functions needed
before committing audio to a recording medium.
Optimizing the MPA575 settings involves five easy steps:
1. Disengage the EQ and HPF.
2. Increase the Gain stepped switch until the red O/L LED lights infrequently, then reduce
the stepped switch by one step.
3. If the compressor is used, first adjust the Sidechain (SC) EQ to position 0 for flat
frequency response.
4. Adjust the compressor Threshold for infrequent lighting of the yellow activity LED.
5. Adjust the Output Level pot until the signal level being provided to subsequent
equipment is appropriate.
Once these basic steps have been taken, the audio timbre may be tweaked by experimenting
with the Mic Load setting, the main EQ, High Pass Filter, the Compressor threshold, and the
compressor Sidechain (SC) EQ.
The Compressor Sidechain EQ can have a surprising effect on the audio tones. The
Sidechain EQ uses the same design as the Main EQ, but the Sidechain EQ is used only to
trigger the Compressor gain reduction, not equalize the Main audio path. As such, the
Sidechain EQ can be set to emphasize certain frequencies, and those frequencies will be
compressed more than the others. For example, a sibilant voice or instrument with excessive
high frequency content can be selectively compressed by turning the Sidechain EQ clockwise
past the center position. High frequencies will be compressed, and low frequencies will be
allowed to pass with little compression. The amount of compression can be set by adjusting
the Threshold level.
Another useful feature to experiment with is the Compressor Pre- Post-EQ button. This button
allows you to choose whether to place the Main EQ before the Compressor or after the
Compressor. This way, the Main EQ can be used as a tool to only alter the tones of the audio
(Compressor Pre-EQ), or can be used as a tool to affect to which tones compression is
applied, and to change the tonal balance of the Main audio path (Compressor Post-EQ).
