Line Inputs; Trim; Insert - Mackie 1642-VLZ Pro Owner's Manual

LINE INPUTS

These 1 / " jacks share circuitry (but not
4
phantom power) with the mic preamps. You
can use these inputs for virtually any signal
you'll come across, from instrument levels as
low as –50dB to operating levels of –10dBV to
+4dBu, as there is 45dB of gain available via
the TRIM knob
.
Note that channels 1-8 line inputs are
intially attenuated by 15dB.
Always be sure to perform the Level-Setting
Procedure .
To learn how signals are routed from these
inputs: . To connect balanced lines to these
inputs, use a 1 / " tip-ring-sleeve (TRS) plug,
4
the type found on some stereo headphones:
RING
Tip = positive (+ or hot)
Ring = negative (– or cold)
Sleeve = shield or ground
To connect unbalanced lines to these in-
1
puts, use a / " mono (TS) phone plug or
4
standard instrument cable:
Tip = signal (+)
Sleeve = ground

TRIM

These controls are the top row of knobs in
the channel strip section. Every time you plug
something into a MIC or LINE input jack, you
should perform the Level-Setting Procedure
, and that procedure is basically "how to use
the TRIM knob."
TRIM adjusts the input sensitivity of the
MIC and LINE inputs. This allows signals from
the outside world to be adjusted to optimal
internal operating levels.
Through the XLR jack (MIC), there will be
0dB of gain with the knob fully down, ramping
to 60dB of gain fully up.
1
Through the / " input (LINE), there is 15dB
4
of attenuation fully down and 45dB of gain fully
up, with a "U" (unity gain) mark at 10:00.
This 15dB of attenuation can be very handy
when you are inserting a signal that is very hot,
or you want to add a lot of EQ gain, or both.
Without this "virtual pad," a scenario like that
might lead to channel clipping.
15-16 only adjust the line level inputs, as they
have no Mic inputs.
effects processors such as compressors, equaliz-
ers, de-essers, or filters . The INSERT point is
after the TRIM control, but before the channel's
EQ, LOW CUT, fader and MUTE controls. Insert
cables must be wired thusly:
SLEEVE SLEEVE RING TIP
TIP
RING
TIP
SLEEVE
Tip = send (to effects device input)
Ring = return (from effects device output)
Sleeve = common ground
DIRECT OUT jacks
be used as channel direct outputs; post-TRIM,
pre-LOW CUT, and pre-EQ. Here are three
SLEEVE SLEEVE TIP
ways you can use the INSERT jacks:
TIP
TIP
SLEEVE
The TRIM controls for
stereo channels 9-10 and 11-
12 are only used to adjust
the Mic inputs. The line in-
puts are set to unity gain.
The TRIM controls for channels 13-14 and

INSERT

1
These / " jacks are for connecting serial
4
ring
(TRS plug)
tip
sleeve
This plug connects to one of the
mixer's Channel Insert jacks.
Even though channels 1–8 already have
, INSERT jacks can also
MONO PLUG
Direct out with no signal interruption.
Insert only to first "click."
MONO PLUG
Direct out with signal interruption.
Insert all the way in to the second "click."
STEREO
PLUG
For use as an effects loop.
(TIP = SEND to effect, RING = RETURN from effect.)
SEND to processor
"tip"
"ring"
RETURN from processor
Channel Insert jack
Channel Insert jack
Channel Insert jack
11