M0070 Professional Preamp User Guide 1.0
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©2009 Microlynx Systems Ltd.
Each of the controls and connectors is described in detail below.
Volume Control
Having the volume control at your fingertips is probably the single most useful feature of the M0070.
When the preamp is mounted behind the tailpiece you can change the volume or mute the signal
without having to precariously balance your instrument while trying to reach over to your main amp.
The volume knob is separate from the other knobs and easy to find.
Phase Switch
Phase differences between the natural sound of the bass and the amplified sound coming from the
amplifier can cause the total perceived sound to be either thin or boomy. The easy to reach Phase
switch on the M0070 inverts the signal to the amplifier and can greatly improve the overall sound.
Variable Rumble Cut
Sub
‐
audible acoustic energy cannot be heard but can stress the power amplifier and in extreme cases
cause permanent damage to the amplifier or speaker. The Rumble Cut is a high
‐
pass filter that
attenuates these sub
‐
sonic signals. The cut
‐
off frequency can be adjusted to suit the instrument and
application.
Three Band Tone Control
The M0070 has a high
‐
performance three band tone control circuit to cut or boost the low, mid and high
frequencies by up to 12 dB. The cut
‐
off frequencies for each of the controls were carefully selected to
be of most use for acoustic bass applications.
The tone control knobs have a center detent to provide a quick tactile indication that they are in their
“flat” position.
Impedance Select Switch
Most modern piezo transducers can operate nicely into a 1 Mohm input impedance. The Impedance
Select switch gives the option to provide a 10 Mohm input impedance when required.
Direct Out with Phantom Power
The M0070 has an XLR Direct Out to connect it to a PA or recording consol using a balanced microphone
cable.
The M0070 will automatically switch to operate off 48 V phantom power if available. A green LED on
the side of the preamp indicates if phantom power is being used.
Ground Lift Switch
This switch can be used to reduce hum caused by ground loops when you simultaneously use the XLR
and phone outputs.
Pre/Post EQ Switch for Direct Out
This switch allows you to select either the raw or equalized signal for the Direct Out.