Allen&Heath GL2400 - Manual (Page 14)

14 GL2400 User Guide
The Console Connectors
MONO CHANNEL MIC / LINE IN The LINE (PAD) switch selects
either the MIC XLR or the LINE TRS jack as the input source. The XLR is
normalled through the TRS jack so that it can be used for microphone or
line level signals when nothing is plugged into the jack socket. This gives
the channel preamp a massive headroom with +34dBu maximum input
capability using XLR or jack. Both inputs are balanced but can be wired
to work with unbalanced signals when
required. The MIC XLR can be switched to
provide +48V DC via 6k8 ohm resistors to
pins 2 and 3 for microphones such as
condensers which require phantom powering.
WARNING: Do not connect unbalanced sources or cables to
the XLR input when 48V phantom power is selected. To avoid loud
clicks always turn the channel off by pressing MUTE when switching
+48V on or off, and when plugging or unplugging cables.
STEREO CHANNEL MIC IN Each stereo channel features a
mono microphone XLR input and two independent stereo line inputs. The
balanced MIC input accepts a maximum +14dBu and can be switched to
provide 48V phantom power.
STEREO CHANNEL MIC OUT The output of the mic preamp is
available on the MIC OUT (BREAKPOINT) TRS jack socket. This is
impedance balanced and operates at a nominal 0dBu line level.
Plugging into this socket breaks the signal into the associated stereo
channel. This means that the mic preamp can be used independently of
the channel, for example to create an ambience mic feed for recording, or
as a preamp for an RTA measurement system.
STEREO CHANNEL LINE IN Stereo inputs ST1 and ST2 feed
channel 15, and ST3 and ST4 feed channel 16 respectively, or can be
routed directly to LR. These inputs use TRS jacks. ST1,3 are
unbalanced, ST2,4 are balanced. Unbalanced inputs automatically
connect the TRS ring to ground when working with balanced sources.
The L input is normalled through the R socket to accept mono signals on
a single jack.
INSERT A single 3-pole TRS jack carries the unbalanced insert signal
for each mono channel and main mix output. Tip = send, Ring = return,
Sleeve = common ground. The channel inserts are post-HPF, pre-EQ
and operate at 0dBu. The group (aux) and LR mix inserts are pre-fader
and operate at -2dBu. Use these to patch in line level signal processing
equipment such as compressors, outboard EQ, delay units and so on.
The wiring of a suitable cable is shown in the diagram.
DIRECT OUTPUT Each mono channel direct output is available on
an impedance balanced TRS jack providing a line level signal operating at
0dBu. The source is set using an internal option jumper for each channel.
The factory default setting is pre-fade (following the pre/post-EQ setting).
This may be changed to post-fade if preferred.
LAMP The 16 channel console has one, the larger models have two
4pin XLR sockets to plug in standard 12V gooseneck lamps to illuminate
the operating surface when working in a dark environment. Only use
lamps intended for this purpose. We recommend the Allen & Heath
LEDlamp with cool white LED illumination and a built in dimmer.
- IN
+IN
3
INPUT
2 1
RING -IN RING
TIP +IN TIP
LINE
MIC
MIC IN
24
LINE IN
DIRECT
INSERT
OUT
24
24
GROUND
RETURN
SEND
RETURN OUT
IN
SEND
PROCESSOR
LINK RING TO SLEEVE TO UNBALANCE
MIC OUT
ST4 ST3
R
L/M
16
R
L/M
MIC IN
16
(BREAKPOINT)
SEND
INSERT
RETURN
TIP
RING
LAMP