Line Inputs, Trim, Insert, Direct OUT | Mackie CR1604

LINE INPUTS

These 1/4" jacks share circuitry (but not 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 –40dB to operating levels of –10dBV to +4dBu, as there is 40dB of gain available via the TRIM knob . 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 1/4" tip-ring-sleeve (TRS) plug, the type found on some stereo headphones:

RING SLEEVE

SLEEVE RING TIP

TIP

RING

TIP

SLEEVE

Tip = positive (+ or hot)

Ring = negative (– or cold)

Sleeve = shield or ground

To connect unbalanced lines to these in- puts, use a 1/4" mono (TS) phone plug or standard instrument cable:

	SLEEVE	SLEEVE TIP
	TIP
	Tip = signal (+)	TIP
	Tip = signal (+)	SLEEVE
	Sleeve = ground	SLEEVE
	Sleeve = ground

TRIM

Yes it’s true, these controls are not located in the patchbay section at all. They’re found along the top row of knobs in the channel strip section. But their purpose is so closely linked with the MIC and LINE input jacks that we couldn’t bear to separate them. Here’s why: 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 10dB of gain with the knob fully down, ramp- ing to 60dB of gain fully up.

Through the 1/4" input (LINE), there is 10dB of attenuation fully down and 40dB of gain fully up, with a “U” (unity gain) mark at 9:00.

This 10dB 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.

INSERT

These 1/4" jacks are for connecting serial 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:

	ring		SEND to processor
tip		(TRS plug)	“tip”
	sleeve
This plug connects to one of the			“ring”
mixer’s Channel Insert jacks.
			RETURN from processor

Tip = send (output to effects device) Ring = return (input from effects device) Sleeve = common ground

Even though channels 1–8 already have DIRECT OUT jacks , INSERT jacks can also be used as channel direct outputs; post-TRIM, pre-LOW CUT, and pre-EQ. Here’s three ways you can use the INSERT jacks:

MONO PLUG

Channel Insert jack

Direct out with no signal interruption to master.

Insert only to first “click.”

MONO PLUG

Channel Insert jack

Direct out with signal interruption to master. Insert all the way in to the second “click.”

STEREO

PLUG

Channel Insert jack

For use as an effects loop.

(TIP= SEND to effect, RING = RETURN from effect.)

DIRECT OUT

Found only on channels 1–8, these 1/4" jacks deliver the signal from the very end of the channel path; post-TRIM, post-EQ, post-LOW CUT, post-fader and post-MUTE. They are the key player in “split monitoring,” making the CR1604-VLZ perfect for an 8-track studio. To wire your own cables: .

TRIM		1
-10dBV
IC GAI
M		N
U
10		60
+10dB		-40dB
AUX	U
	U
1
OO		+15
	U
2
OO		+15
PRE
	U
3		5
OO		+15
	U
4		6
OO		+15
5/6
SHIFT
EQ	U	HI
		12k
-15		+15
	U	MID
-15		+15
800
200		2k
100		8k
	U	LOW
		80Hz
-15		+15
LOW CUT
75 Hz
18dB/OCT
PAN
L		R
1
MUTE
		OL
		-20
		SOLO
		1–2
		3–4
		L - R
		OO