PreSonus MP20 - Manual (Page 6)

OVERVIEW
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headroom on each channel. This feature gives you a very
wide dynamic range and excellent transient response
characteristics.
? Rumble Filter. A Rumble filter is provided on each
channel for eliminating low frequency noise. This lets you
greatly reduce background noise such as air conditioners
or wind noise with the flick of a switch without effecting the
desired frequencies.
? Microphone or Instrument Input. Each channel of the
MP20 has a separate XLR microphone input on the rear of
the unit and a female 1/4” instrument input jack located on
the front panel.
? High Quality Transformer with IDSS Control. The
MP20 offers a high quality transformer on each channel.
These feature an IDSS control (this control adjusts the
drain current on the input FET amplifier altering the even
harmonic levels of the signal being passed) with an
adjustment range of 0% to 100%. The 0% position
passes a pure signal. As the control is rotated to the
100% position, the signal’s even harmonic series is
boosted giving the signal “warmth” very much like a
vacuum tube or similar to the sound of analog tape
saturation. This remarkable effect gives you the sound of
a tube without the headache of uneven performance often
encountered with vacuum tube devices ( no tube to pick-
up RF or to age and become “microphonic”)
? Mix Bus. The MP20 has a stereo summing bus for
combining the input signals assigned to the bus using the
L/R function switch on the front panel of the MP20. A pan
knob allows the placement of the selected signal
anywhere in the stereo array of the stereo summing bus
out-going signal (i.e.- left; left-center; center; right-center or