User guide
GL2800 User Guide                   15 
GROUP, L, R, M OUT
 The main console mix outputs are on 
electronically balanced XLR. These produce the professional standard 
+4dBu when the meters read ‘0’, and provide up to a maximum +26dBu. 
The L, R and M outputs typically feed the house PA system in live sound 
mixing, or 2-track and mono recorders in studio mixing. In monitor mode
, 
these outputs reverse with the Aux TRS jack connections. 
AUX OUT 1-10 Each aux send is available on an impedance 
balanced TRS jack operating at -2dBu line level. An internal option is 
available to fit a balanced line driver IC to provide an electronically 
balanced output operating at +4dBu. Note that it is not usual to require 
this option as the impedance balanced standard drive provides sufficient 
interference rejection when feeding balanced equipment inputs. The aux 
sends are typically used to feed monitors, effects devices such as reverb 
and delay, and for special mix requirements. In monitor mode
, these 
outputs reverse with the group and LR XLR connections. 
MATRIX OUT 1-4 Each matrix output is available on an impedance 
balanced TRS jack operating at -2dBu line level. An internal option is 
available to fit a balanced line driver IC to provide an electronically 
balanced output operating at +4dBu. The matrix outputs are typically 
used for stereo or mono recording or broadcast feeds, delay and fill 
speakers, zone feeds, additional monitors such as IEM, hearing assist 
loops and so on. 
MATRIX EXT IN 1-4 Each matrix has an unbalanced 0dBu line level 
TRS jack input. An external signal such as ambience mix, additional or 
sub mixer, remote source, reference tone and so on may be mixed in to 
each matrix. The inputs are normalled as shown in the diagram here.  
This means that you can plug in just one jack (EXT1) as a common 
source to all matrix, two jacks (EXT1,2) as a common stereo source to 
matrix pairs, or four independent sources. This is ideal for adding mono 
or stereo ambience to recordings or in-ear monitors fed from the matrix. 
2-TRACK IN and OUT Unbalanced TRS jack outputs and TRS 
inputs connect to popular recording and playback devices such as CD,  
MiniDisc, computers and tape machines. Nominal line level is -2dBu.  
The 2-track SEND always follows the post-fade LR mix regardless of 
mode switch configuration. The 2-track RETURN can be used for 
monitoring a mono or stereo recording, or as a simple input for playback 
of walk-in and background music. The L input normals through the R 
socket for plugging in a mono source on a single jack. 
MONITOR OUT These impedance balanced line level TRS jack 
outputs follow the post-level monitor signal. Separate sockets are 
provided for the L and R signals. Use these to feed local speaker or other 
monitor systems. 
SYS-LINK V2 OPTION Blank plates are fitted here as standard.  
The GL2800 Sys-Link V2 (version 2) input/output option kit is available 
from Allen & Heath. Refer to OPTIONS later in this guide. 
(WEDGE)MOUT
OUT
TB/GEN
(L)(R)
10
AUX AUX
9
(GRP)(GRP)(GRP)(GRP)(GRP)(GRP)(GRP)(GRP)
(GRP/AUX REVERSE)
8
AUX AUX
7
AUX
6
AUX
1
AUX
2
AUX
3
AUX
4
AUX
5
GRP
2(AUX)(AUX)GRP(AUX)GRP(AUX)GRP(AUX)GRP(AUX)GRP(AUX)GRP 345678 (AUX) 1GRPOUT LROUT (9)(10)
IN2TRK
R
L/M
R
L
OUT
MATRIX EXT IN
(COMMON)
3
MTX OUT
4
MTX OUT
2
MTX OUT
1
MTX OUT
MTXMTX MTX MTX
IN IN IN IN
3421
Operating Modes 
In FOH mode, LR and M feed 
the main PA. Groups outputs 1-
8 may be used for multitrack 
recording, zone feeds and so 
on, or simply left unconnected 
where they are used as 
‘subgroups’ to LRM for level 
masters and/or inserted 
processing. 
In monitor mode
 Groups 1-8 
and LR XLRs and inserts 
become the 10 aux mix 
masters. Stereo Aux 9-10 is 
available on the LR XLRs. M 
becomes the engineer’s listen 
wedge AFL/PFL feed. This 
configures the console with 10 
main stage monitors and an 
engineer’s output. The groups 
and LRM mix are still available 
via the matrix to provide yet 
more monitor feeds from the 4 
matrix outputs. 
IN1
IN2
IN3
IN4
MATRIX EXT IN
OUT
RL
MONITOR










