Front Panel; Side Panel - Universal Audio Apollo x4 Hardware Manual

(k) MONO
Sums the left and right signals of the stereo monitor mix into a monophonic signal.
MONO applies to the monitor outputs only. It does not apply to the headphone outputs.
(l) MUTE
Mutes the monitor outputs. When MUTE is active, the MONITOR Selected Indicator (5)
is always lit RED (including when in Preamp mode). When MUTE is active in Monitor
mode, the Volume Level Indicators (2) are also RED.
Note: MUTE does not apply to the headphone outputs. Headphone outputs cannot
be muted.

Front Panel

Refer to the illustration below for numbered control descriptions in this section.
13
(13) Hi-Z Instrument Inputs
21 OUT
These are the Hi-Z inputs for channels 1 and 2. Connect any guitar, bass, or other high
20
19
impedance instrument here. These jacks automatically override the mic and line inputs
for the channel. OFF
Levels for the Hi-Z inputs are set using the same method as the mic and line inputs.
Note: These jacks accepts a ¼" mono TS (tip-sleeve) plug only.
(14) Headphone Outputs
These are the stereo outputs for headphones 1 and 2. The jacks accept ¼" stereo
headphones. The volume of each headphone output is independently controlled with the
Level knob (1) when HP1 or HP2 is selected (5) with the MONITOR button (12).

Side Panel

Kensington Security Slot (not shown)
The anti-theft security slot on the side panel connects to any standard Kensington lock.
Apollo x4 Hardware Manual
OUT
3 4
6
7
8
1 2
Front panel elements
OPTICAL LINE OUT LINE OUT MONITOR
3 1
IN
4 2
POWER
ON 12VDC
18 17 16
OPTICAL LINE OUT LINE OUT MONITOR
3 1
IN
4 2
POWER
1 2
5
PREAMP MONITOR
9 10 11 12
L
MIC/LINE 4 MIC/LINE 3 MIC/LINE 2
R
15
PREAMP MONITOR
27
L
MIC/LINE 4 MIC/LINE 3 MIC/LINE 2
R
1 2
14
MIC/LINE 1
Controls & Connectors
MIC/LINE 1