Front Panel Description - Mackie SRM150 User Manual

FRONT PANEL DESCRIPTION

Most of the connections and controls on the SRM150
are located on the front panel for easy access.
Channels 1 and 2 have Neutrik® combo connectors,
which accept balanced microphone inputs from an XLR
connector, or balanced and unbalanced line-level inputs
from a 1/4" TRS or TS connector.
The XLR inputs are wired as follows:
Pin 1 = Shield or ground
Pin 2 = Positive (+ or hot)
Pin 3 = Negative (– or cold)
The 1/4" inputs are wired as follows and will accept
both balanced and unbalanced inputs:
Sleeve = Shield or ground
Tip = Positive (+ or hot)
Ring = Negative (– or cold)
Channel 3 has a pair of RCA connectors, which accept
a stereo line-level input from a CD player or MP3 player
(or any other line-level device).
These are used to adjust the signal level for each
individual channel. Since the SRM150 incorporates
Mackie's world-class low-noise mic preamp technology,
you can connect either a line-level or a microphone-level
signal to the input, and use this control to adjust the
level correctly.
Follow the Quick Start guide on page 4 for setting
the gain controls. For most applications, it will be in
the 12 o'clock position. If you have a particularly high
line-level signal connected to the SRM150, you may
need to turn the control down to the 9 o'clock position.
If you have a low line-level or mic-level signal con-
nected, you may need to turn the gain control up to the
3 o'clock position.
Push in this button to change the 1/4" line input
on channel 1 to an instrument input. When the but-
ton is out, the 1/4" input accepts normal line-level
signals from low-impedance sources. When the button
is pushed in, the 1/4" input accepts high-impedance
signals from instruments with electric pickups, which
you would normally run through a DI box.
8
Plugging a guitar straight into a
typical line-level input can result in
the loss of gain, especially at high
frequencies, resulting in a dull sound.
Normally, you must use a direct box
between a guitar and a mixer's or preamplifier's input,
which serves to convert the impedance of the guitar
from high to low. The Instrument input on channel 1
makes the need for a direct box unnecessary. It's like it
has its own built-in direct box!
However: The Instrument input is unbalanced, so if you
are running a long cord between the instrument and the
SRM150 (say over 20 feet), it is best to use a direct box
with a balanced output to avoid picking up noise over
the length of the cord.
Most professional condenser microphones require phan-
tom power, which is a low-current DC voltage delivered
to the microphone on pins 2 and 3 of the XLR micro-
phone connector. Push in the 48V button if your micro-
phone requires phantom power. An LED lights next to
the button to indicate that phantom power is active.
MAIN
OFF MAX
LEVEL
PHANTOM POWER
48V
INSTRUMENT (CH 1)
1
MIN MAX MIN
MIC/LINE
MIC/LINE
SRM150
EQ
U
HIGH
12kHz
-15 +15
U
MID
2.5kHz
-15 +15
U
LOW
100Hz
-15 +15
2 3
MAX MIN MAX
L
R