26 GB4 User Guide
Mono Input

MIC GAIN (1) adjusts the sensitivity of both mic (XLR) and Line (1/4” jack) inputs. Both inputs

are electronically balanced, and are located on the rear connector panel.

The PEAK LED (2), monitors two points in the audio path: pre-insert point and post-EQ.

The 48V switch (3) applies 48V phantom power to the input XLR. An adjacent LED indicates

when the phantom power is on.

The PHASE switch (4) reverses the phase of the selected input.

HI-PASS (5) switches in the high-pass filter.

The module insert point is pre-EQ , pre-fader. It is located on the rear connector panel.

The EQ section (6) is four band, with shelving HF and LF, and swept peaking high and low mid

sections.

The HF and LF sections give +/-15dB cut/boost at 12kHz and 60Hz respectively. The Lo-mid

section gives +/-15dB cut/boost at 80Hz-1.9kHz. The Hi-mid section gives +/-15dB cut/boost at

550Hz-13kHz.

The section is switched in by the EQ switch (7).

Signal is sent to the AUX 1-8 busses via individual level pots (8). Aux 1- 4 are pre fader signals,

whilst Aux 5-8 are globally selectable pre or post fade via switches on the master section.

Signal for the L+R (main mix), 1-2 group busses and 3-4 group busses are routed via the PAN

pot (9). The pan pot positions the signal within the stereo image.

The signal in the module is turned on and off by the illuminated MUTE switch (10), and also the

master mutes M1-M4 from the master section, if they are selected using the M1 - M4 switches

(11).

Post-fader signal level is controlled by a 100mm fader (12).

The signal is sent to the stereo mix bus, centre bus and 4 group busses using the C, L+R, 1-2

and 3-4 switches (13). Note the use of group 1 & 2, and group 3 & 4 as 2 sets of stereo pairs.

A 4-segment LED bargraph meter (14), next to the fader, meters the signal post-EQ, pre-mute,

pre-fade. The meter has a peak type response.

The PFL switch (15) feeds the pre-mute, pre-fade signal to the monitor output and phones

output. An adjacent LED indicates when the PFL is on.

EQEQ

HI

MID

HF

LO

MID

LF

15
12
9
6
33
6
9
12
15
-+
0
15
12
9
6
33
6
9
12
15
-+
0
550 13k
3k
80 1.9k
450
15
12
9
6
33
6
9
12
15
-+
0
15
12
9
6
33
6
9
12
15
-+
0
60dB
30
5
100Hz
GAIN
MIC
48V
PK
LINE
-20
=
10
5
0
5
10
15
20
30
+16+8
0
-10
M
1
M
2
M
3
M
4

C

1
2

L

R

3
4

PFL

6
0
+
6
0
+
6
0
+
6
0
+
6
0
+
6
0
+
6
0
+
6
0
+

AUX1

AUX2

AUX3

AUX4

AUX5

AUX6

AUX7

AUX8

PAN

PRE
PRE
PRE
PRE
POST
POST
POST
POST
PRE
PRE
PRE
PRE
R
L
0

MUTE

1
1
1
3
4
5
6
7
15
10
11
8
12
13
9
14
2